AGW Scientifc Certainty
Robbo
I suspect that claims about the certainty of climate science matter
more for the perception of future risk, and for political reasons,
than as a realistic statement of the state of the science. I believe
that most scientists and engineers must understand something of the
problems and uncertainties in our understanding of such a complex and
dynamic system. Some of this is spelled out by the IPCC. LOSU – the
“level of scientific understanding.” The LOSU for some critical
elements of the system is low to medium.
Even such a seemingly simple question as to the rate of recent warming
is subject to wide interpretation. Climate fluctuates strongly –
principally in line with ENSO. Large interannual and decadal changes
in surface temperature makes the interpretation of trend sensitive to
both the end points and to the length of the record.
Period Trend (degrees C/decade)
1900 - 2008 0.07
1945 – 2008 0.11
1958 – 2008 0.13
1979 – 1997 0.11
1976 – 2008 0.17
Table 1: A quick comparison of periods and temperature trends
The evaluation of a warming trend depends on a reasonable scientific
justification for the period over which trends are assessed. The
1900-2008 period is certainly the longer term but misses much of the
period of high carbon emissions. 1945-2008 is justifiable – it is the
period of strongly increasingly carbon emissions. 1958 to 2008 is the
last 50 years in accordance with the period adopted by the IPCC. It
has been argued that the trend between 1979 and 1997 is the rate of
forced warming when nonlinear climate behaviour (discussed below) is
accounted for. The rate of warming between 1976 and 2008 is the usual
trend claimed – but arguably the trend is evaluated over too short a
period because of multidecadal variation of ENSO and other
factors.
Thompson et al (2009) filter out ENSO, the effects of aerosols emitted
by explosive volcanic eruptions, and “variations in the advection of
marine air masses over the high latitude continents during winter,”
which they term “dynamically induced variability.” The temperature
bottom line of this study was a trend of 0.12 degrees centigrade per
decade from 1950.
There is a satellite based temperature record of the lower
atmosphere. This has global coverage and a trend that is less than
the surface station methodologies.
“Using NOAA satellite readings of temperatures in the lower
atmosphere, scientists at The University of Alabama in Huntsville
(UAH) produced a dataset that shows global atmospheric warming at the
rate of about 0.07 degrees C (about 0.13 degrees Fahrenheit) per
decade since November 1978,” said Dr. John Christy, who compiled the
comparison data. “That works out to a global warming trend of about
0.7 degrees centigrade over 100 years. That's a definite warming
trend, which is probably due in part to human influences. But it's
substantially less than the warming forecast by most climate models,
and it isn't entirely out of the range of climate change we might
expect from natural causes.”
The rate of recent warming is of critical importance in evaluating the
social and environmental risk of global warming – and it is probably
the easiest aspect of climate science to spin in the required
direction.
Temperature increased in the last decades of the 20th Century to a
peak in the large (~ 50 year frequency) 1998 El Niño and has been a
little cooler since. Temperature has not increased by 0.2 degrees
centigrade over the past decade as predicted by the IPCC. That is the
simplest part of climate science. The more pertinent factors in our
limited knowledge of climate include solar, cloud and complex system
uncertainties.
Solar
Scafetta and West (2007) find a large solar influence on global
temperature in the 20th Century.
“A phenomenological thermodynamic model is adopted to estimate the
relative contribution of the solar-induced versus anthropogenic-added
climate forcing during the industrial era. We compare different
preindustrial temperature and solar data reconstruction scenarios
since 1610. We argue that a realistic climate scenario is the one
described by a large preindustrial secular variability (as the one
shown by the paleoclimate temperature reconstruction by Moberg et al.
(2005)) with the total solar irradiance experiencing low secular
variability (as the one shown by Wang et al. (2005)).
Under this scenario the Sun might have contributed up to approximately
50% (or more if ACRIM total solar irradiance satellite composite
(Willson and Mordvinov, 2003) is implemented) of the observed global
warming since 1900.”
Satellite monitoring of solar irradiance commenced in the late
1970's. The record is marred by having three instruments with
intercalibration and drift problems as well as a 2 year gap following
the Challenger disaster. The records have been “stitched” together
but with conflicting results. NASA’s SORCE project since 2003 will
provide more reliable data on future total solar irradiance (TSI)
changes.
Climate model TSI inputs favour constant solar irradiance for the 21st
Century - or irradiance varying about a constant mean in 11 year
cycles. Solar activity has 11 year (approximately) sunspot cycles, 22
year magnetic reversal cycles and changes in activity over the mid to
very long term. Solar activity peaked in last centuries “Modern Grand
Maxima.” It is much the safest bet in climate science that solar
activity is declining steeply from the recent high point.
Clouds
“The new method is a conceptual breakthrough in how we analyze data,”
said Anthony Del Genio, a scientist at the Goddard Institute for Space
Studies.
“What it shows is remarkable," said Dr. Bruce Wielicki of NASA’s
Langley Research Center. "The rising and descending motions of air
that cover the entire tropics, known as the Hadley and Walker
circulation cells, appear to increase in strength from the 1980s to
the 1990s. This suggests that the tropical heat engine increased its
speed. The faster circulation dried out the water vapor that is
needed for cloud formation in the upper regions of the lower
atmosphere over the most northern and southern tropical areas. Less
cloudiness formed allowing more sunlight to enter and more heat to
leave the tropics. It's as if the heat engine in the tropics has
become less efficient using more fuel in the 90s than in the 80s. We
tracked the changes to a decrease in tropical cloudiness that allowed
more sunlight to reach the Earth's surface. But what we want to know
is why the clouds would change.”
The results show cloud cover in the tropics to be more variable than
previously thought. “It suggests that current climate models may, in
fact, be more uncertain than we had thought,” Wielicki added. “Climate
change might be either larger or smaller than the current range of
predictions.”
“The observations capture changes in the radiation budget-the balance
between Earth's incoming and outgoing energy-that controls the
planet's temperature and climate. The previously unknown changes in
the radiation budget are two to four times larger than scientists had
believed possible. The reason why and the degree to which it changed
are surprising scientists and create a powerful new test for climate
models.”
“The question is, if this fluctuation is due to global climate change
or to natural variability," said Del Genio. "We think this is a
natural fluctuation, but there is no way to tell yet.”
Large changes in cloud cover are being observed in the International
Satellite Cloud Climatology Project (ISCCP) record from 1984. The
radiation effect of Earth albedo changes is estimated by Pallé et al
(2009) at a 4 W/m2 increase of shortwave radiation at the surface from
1984 to 1998 and a decrease of 2.7 W/m2 between 1999 and 2008. The
changes in Earth’s radiation budget are climatologically
significant.
Complexity
Climate shifts occurred 4 times in the last 100 years around 1910, the
mid 1940’s, the mid 1970’s and 1998/2001 (Tsonis et al, 2007, Swanson
et al 2009). Small changes in forcings (solar, gases and aerosols,
albedo) are alternately amplified and damped (nonlinear) by global
climate processes and climate then oscillates for a time around a
different climate mean. Climate shifts can be seen in the inflection
points of the global near surface temperature record. Warming after
1910, a little cooler between the mid 1940’s to the mid 1970’s,
warming to 1998 and a little cooler since.
The direct impact of greenhouse gas increase since the start of
industrialisation is about 0.5 degrees centigrade of global
temperature increase theoretically. It is not insignificant as energy
in the climate system. The total effect is unknown because it feeds
into a dynamic climate system of sun, orbit, ocean, atmosphere, ice,
clouds, gases and aerosols operating interactively. All of these
change all the time. The exponential growth of ice cover is
implicated as a causal factor in ice ages - extreme nonlinear climate
events. Global cloud cover has been known to change from ISCCP data
collected from 1984 and the argument has been about cause and effect.
There is a little more cloud cover since about 1999 - which came first
the clouds or the current cooling? The question is not answerable as
climate is dynamic and complex. Small changes in initial conditions
lead to climate fluctuation which then settles into a different
climate state – until the next unpredictable climate shift.
At the policy level – and here I am speaking as an engineer, an
environmental scientist and as a human being - it is a matter of
social, economic and environmental risk.
Increasing greenhouse gases increases forced complex system
instability - accepted. But I don’t accept that there is a social
trade off to be made. In a sense the accuracy or otherwise of climate
science makes very little difference to sensible policy. Carbon cap
and trade is emphatically not sensible environmental or social
policy. Recent calculations by Bjorn Lomberg point to a business as
usual increase of carbon dioxide in the atmosphere from 1990 to 2012
of 42.7% without Kyoto. The increase with Kyoto will be about 42.2%.
Far more effective to maintain economic growth (as environmental
scientists have long argued) and thereby have the confidence and
resources to drive both technological innovation and environmental
conservation. All of the environmental problems, including
population, are made easier with economic development.
While the lack of a recent (10 year) trend in atmosphere and ocean
temperatures continues there is a less urgent environmental risk.
Given the rate of technological evolution – a matter of decades at
most is all that is required to develop dozens of low cost options for
energy and development.
The global economy is itself a complex and dynamic system. The only
way to maintain high rates of global economic development is to have
honesty and constancy in economic governance, continued economic
growth and good luck. The consequences of the economic risk of carbon
taxes or charges – are more than significant. Thankfully widespread
support for much more of a much to be feared command and control style
economy is limited to noisy “ecosocialists”. The most extreme
economic risk leads to hunger for hundreds of millions of
people.
Pallé, E., P. R. Goode, and P. Montañés-Rodríguez (2009), Interannual
variations in Earth's reflectance 1999–2007, J. Geophys. Res., 114,
D00D03, doi:10.1029/2008JD010734.
Thompson, D.W.J., J.M. Wallace, P.D. Jones, and J.J. Kennedy, 2009:
Identifying Signatures of Natural Climate Variability in Time Series
of Global-Mean Surface Temperature: Methodology and Insights. J.
Climate, 22, 6120–6141.
Tsonis, A. A., K. Swanson, and S. Kravtsov (2007), A new dynamical
mechanism for major climate shifts, Geophys. Res. Lett., 34, L13705,
doi:10.1029/2007GL030288.
Scafetta, N., and B. J. West (2007), Phenomenological reconstructions
of the solar signature in the Northern Hemisphere surface temperature
records since 1600, J. Geophys. Res., 112, D24S03, doi:
10.1029/2007JD008437.
Swanson, K. L., and A. A. Tsonis (2009), Has the climate recently
shifted?, Geophys. Res. Lett., 36, L06711, doi:10.1029/2008GL037022.
Don Libby
Newsgroups: gmane.science.general.global-change
To: "globalchange" <global...@googlegroups.com>
Sent: Friday, December 25, 2009 5:14 PM
Subject: [Global Change: 3323] AGW Scientifc Certainty
>Period Trend (degrees C/decade)
>
>1900 - 2008 0.07
>1945 � 2008 0.11
>1958 � 2008 0.13
>1979 � 1997 0.11
>1976 � 2008 0.17
>
>Table 1: A quick comparison of periods and temperature trends
let y=temperature, let t=time
dy/dt >0 for all t > 0.
Does that tell you something?
Thanks,
-dl
Phil Hays
> There is a satellite based temperature record of the lower
> atmosphere. This has global coverage and a trend that is less than
> the surface station methodologies.
Err, maybe, maybe not. Yes, the UAH (University of Alabama in
Huntsville) interpretation of the satellite shows a trend lower than the
surface trend. But that's not the only interpretation of the satellite
data. Which I'm sure isn't news to almost everyone reading this.
Including you.
So why didn't you mention the other interpretations?
--
Phil Hays <phil...@ieee.org>
Eric Swanson
http://www.spaceref.com/news/viewpr.html?pid=11540
John Christy has been proven wrong repeatedly. That particular quote
came out before I showed that there was a problem with the UAH TLT
over the Antarctic. One of the other groups which now produce a data
set from the MSU (Remote Sensing Systems, RSS) excludes all data over
the Antarctic (that is, poleward of 70S) the reason being the high
elevations there. RSS also excludes data from other locations with
high elevations.
Curisty's latest results show a global trend of 0.13 C/decade, but
0.19C/decade for the Northern Hemisphere and only 0.06C/decade for the
Southern Hemisphere. Could it be Christy's results are wrong for the
SH because of the problems over the Antarctic? Is the South Pole
really cooling as his data shows, -0.06 C/decade? Is there a problem
with the ozone layer down there?
http://vortex.nsstc.uah.edu/data/msu/t2lt/uahncdc.lt
Oh, BTW, Christy fudges the data over the poles, interpolating to fill
in the missing data poleward of 82 degrees. Really now, isn't the
same complaint as has been directed at the CRU, only we know for a
fact he's doing it?
I'll believe you are serious when you write Inhoffe and alert him to
the problem...
E. S.
--------------------------------------------------------
On Dec 25, 6:14 pm, Robbo <rob...@robertellison.com.au> wrote:
> Some major uncertainties in climate science
[cut]
>
> There is a satellite based temperature record of the lower
> atmosphere. This has global coverage and a trend that is less than
> the surface station methodologies.
>
> “Using NOAA satellite readings of temperatures in the lower
> atmosphere, scientists at The University of Alabama in Huntsville
> (UAH) produceda dataset that shows global atmospheric warming at the
> rate of about 0.07 degrees C(about 0.13 degrees Fahrenheit) per
> decade since November 1978,” said Dr.John Christy, who compiled the
Alastair
The point to note is that we live on the surface of the planet, not in
the upper troposphere where the satellites are measuring the
temperature. If the satellite measurements are correct, which I
believe thout it seems tha Phil like many others does not, then that
means that the models are wrong! Not that global warming is not
happening.
If the models are wrong that does not mean that they are over-
estimating the warming, though that is what the sceptics want to
believe.
Cheers, Alastair.
Robbo
Not exactly cherry picking - you have to understand something of the
theory of complex systems as it applies to climate.
But it is not relevant to policy. The policy question is what is the
best methodology for reducing greenhouse gas emissions most
quickly.
On Dec 26, 12:14 pm, "Don Libby" <dli...@tds.net> wrote:
> From: "Robbo" <rob...@robertellison.com.au>
> Newsgroups: gmane.science.general.global-change
> To: "globalchange" <global...@googlegroups.com>
> Sent: Friday, December 25, 2009 5:14 PM
> Subject: [Global Change: 3323] AGW Scientifc Certainty
>
> >Period Trend (degrees C/decade)
>
> >1900 - 2008 0.07
> >1945 2008 0.11
> >1958 2008 0.13
> >1979 1997 0.11
> >1976 2008 0.17
Robbo
periods. The critical point - whatever source is used - is that start
and end points influence trend estimation because of large interannual
variation that is mostly due to ENSO. I believe that the trend
estimated by Kyle Swanson this year at realclimate and by Thompson et
al 2009 - about 0.08 to 0.12 degrees C/decade is about right. This
seems to make the IPCC prediction of a continuing increase over the
next few decades of 0.2 degrees C unlikely along with the higher model
projections(up to 6 degrees) this century.
I do not understand what your point is? That the rate of recent
warming is 0.13 degrees C/decade?
All of the various methodologies have evolved over the years as
methods improve - what I see is that the results from all of the
methodologies are converging as they should with a better
understanding.
To my mind - the problem is no longer scientific but what policy
response can best and most quickly achieve reductions in emissions. I
agree with the Lomberg approach. I will happily write to Inhoffe to
say this - got an email?
Eric Swanson
quote by John Christy. In that quote, Christy claimed the trend for
the satellite data was "about 0.07 degrees C (about 0.13 degrees
Fahrenheit) per decade". That value is about half of that which
Christy's latest results indicate, which may still be understating the
rate of warming.
Also, taking 10 year periods to calculate trends is basically wrong.
Climate trends are usually defined over longer periods, often 30
years. Using arbitrary 10 year periods can present distorted results,
as there are short term variations, such as the El Nino/La Nina
oscillations or the 11 year (mol) sunspot cycles. Your choice of 1998
as a start date is a perfect example of the problem, as 1998 was an
unusually warm year in the longer term record. Calculating a trend
with that start date will obviously produce a lower trend.
As you note, this has been discussed on RealClimate and elsewhere.
Why did you bring it up in your reply? Are you attempting to deflect
attention away from the fact that you used an old quote from Christy,
one which understates the trend? Where did you find the quote which
you pasted into your post? Was it a denialist web site and if so,
which one?
Lomborg is not an atmospheric scientist and his writings are full of
errors. His latest is no better.
Lomborg has repeatedly claimed that spending money to address climate
change results in spending less resources fore poorer nations. He
forgets that the problem is ultimately population multiplied by the
consumption per capita. Attempts to raise the standard of living of
the masses in poor countries will mean much greater environmental
problems, as well as further increases in population. Ultimately, the
Earth's human population is likely to hit a situation, such as Peak
Oil, which will result in population crash, that is a massive die
off. Claiming that the world's poor should rise to the level of
wealth of Western nations is dancing around this real problem and
isn't going to fix anything in the long run...
Inhofe is one of the senators from Oklahoma, if you didn't know.
http://www.youtube.com/watch?v=P70SlEqX7oY
http://www.youtube.com/watch?v=eJFZ88EH6i4
E. S.
---------------------
Nolin, Kenneth M.
> > social and environmental risk of global warming - and it is probably
> > the easiest aspect of climate science to spin in the required
> > direction.
>
>
--
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Nolin, Kenneth M.
-----Original Message-----
From: global...@googlegroups.com
[mailto:global...@googlegroups.com] On Behalf Of Eric Swanson
Sent: Sunday, December 27, 2009 8:07 AM
To: globalchange
http://www.youtube.com/watch?v=P70SlEqX7oY
http://www.youtube.com/watch?v=eJFZ88EH6i4
--
Robbo
in the big El Nino of 1998. A wider significance of this is addressed
in the Tsonis et al and Swanson and Tsonis papers referenced - a
sudden climate shift in 1998/2001. Climate seen as a nonlinear
oscillator - a complex system in chaos theory. It seems possible that
the current cool mode will persist for another decade or two - until
the next multidecadal climate shift. New and startling science I know
- but as implacably logical as the Special Theory of
Relativity.
The current temperature trend is flat but any trend is masked by large
interannual variation mostly due to ENSO - making it impossible to be
definitive especially over shorter periods. Over longer periods of 50
or more years - the trend is about 0.1 degrees centigrade/decade.
Using the period of recent warming - 1976 to 1998 - includes two
periods of large climate fluctuation - the 1976/1977 'Great Pacific
Climate Shift' and the 1998/2001 climate shift - and distorts the true
rising trend. The other reference I cited was Thompson et al - who
filtered ENSO, volcanos and 'dynamically induced variability' from the
record. Reasonable estimates of the recent trend are about 0.1
degrees/decade.
My post is a little disjointed - I started writing about scientific
uncertainty. But I think that greenhouse gas emissions need to be
reduced ASAP. The policy question is what the most effective way of
doing that is. My belief is that continued economic growth and the
technological path is the way to go. There are numbers of options for
power and transport. Cheap solar photovoltaic would be fantastic for
the developing world. Solar accumulators, high temperature nuclear
reactors, energy efficiency - literally dozens of emerging
technologies. Peak oil is a nonsense - there are many alternative
sources of carbon. Including coal gasification and liquefaction, tar
sands and shale oil - literally a thousand years of fuel supplies.
More exotic means of fuel production include high temperature
hydrolosis to create hydrogen which can then be combined with carbon
dioxide to produce liquid fuels.
It is interesting that Lomberg is wrong and a skeptic because - pretty
much as I do - he accepts that greenhouse gas emission reductions are
necessary. It shows that the issue is not scientific - science is a
threadbare justification for ever wilder claims of imminent doom. It
is economics and politics.
'Limits to growth' ideas are dangerous bullshit that put many lives
and legitimate human aspirations at risk. It matters a lot because we
have already seen food riots as a result of the misallocation of
global resources. But ecosocialism is not going to happen. Most of
the world want cheaper and more abundant fuels - and cars, washing
machines and air conditioners.
Eric Swanson
On Dec 27, 4:22 pm, Robbo <rob...@robertellison.com.au> wrote:
> Temperatures peaked (in every record of monthly temperature anomalies)
> in the big El Nino of 1998. A wider significance of this is addressed
> in the Tsonis et al and Swanson and Tsonis papers referenced - a
> sudden climate shift in 1998/2001. Climate seen as a nonlinear
> oscillator - a complex system in chaos theory. It seems possible that
> the current cool mode will persist for another decade or two - until
> the next multidecadal climate shift. New and startling science I know
> - but as implacably logical as the Special Theory of
> Relativity.
There's another situation which may have impacted the climate of the
late 1970's. It was called The Great Salinity Anomaly and was a large
pool of relatively fresh water which circulated around the North
Atlantic Sub Polar Gyre. About the same time, measurements indicated
that the formation of bottom water in the Greenland Sea had ceased.
That's like what may happen if the Thermohaline Circulation (THC) were
to weaken or stop and most climate models coupled to dynamic ocean
models predict that the THC will stop as the climate warms.
http://www.whoi.edu/oceanus/viewArticle.do?id=2344&archives=true
One area in the Western Greenland Sea has exhibited changes associated
with a reduction in THC in that area for the past two winters. The
same pattern appears to be repeating so far this winter. Note the
suggestion that the GSA was the result of increased flow of sea-ice
out of the Arctic in 1967. That outflow has happened again these past
few years. Only this time, it may not stop if the Arctic sea-ice
melts away and opens the floodgates...
> The current temperature trend is flat but any trend is masked by large
> interannual variation mostly due to ENSO - making it impossible to be
> definitive especially over shorter periods. Over longer periods of 50
> or more years - the trend is about 0.1 degrees centigrade/decade.
> Using the period of recent warming - 1976 to 1998 - includes two
> periods of large climate fluctuation - the 1976/1977 'Great Pacific
> Climate Shift' and the 1998/2001 climate shift - and distorts the true
> rising trend. The other reference I cited was Thompson et al - who
> filtered ENSO, volcanos and 'dynamically induced variability' from the
> record. Reasonable estimates of the recent trend are about 0.1
> degrees/decade.
See above. The PDO may be associated with changes in the THC in the
North Atlantic.
> My post is a little disjointed - I started writing about scientific
> uncertainty. But I think that greenhouse gas emissions need to be
> reduced ASAP. The policy question is what the most effective way of
> doing that is. My belief is that continued economic growth and the
> technological path is the way to go. There are numbers of options for
> power and transport. Cheap solar photovoltaic would be fantastic for
> the developing world. Solar accumulators, high temperature nuclear
> reactors, energy efficiency - literally dozens of emerging
> technologies. Peak oil is a nonsense - there are many alternative
> sources of carbon. Including coal gasification and liquefaction, tar
> sands and shale oil - literally a thousand years of fuel supplies.
> More exotic means of fuel production include high temperature
> hydrolosis to create hydrogen which can then be combined with carbon
> dioxide to produce liquid fuels.
Peak Oil is a fact. Every oil field goes thru a period of growth then
followed by decline requiring ever more effort to continue
production. The sum of all the oil fields on Earth will also provide
a similar production path. At some point in time, production or
conventional oil will peak and begin to decline. Surely, there are
other sources of hydrocarbons which can be used to make liquid fuels,
but the Energy Return On Energy Invested (EROEI) for all these sources
is less than that for the easy to get at oil we so carelessly burned.
Tar Sands are a prime example, as natural gas is used to separate the
dense tar from the mixture. There are no commercial operations which
produce oil from oil shale, so we don't know how that might work out,
but we do know the processes so far proposed use lots of energy. When
the cheap energy is used up, the remaining fossil energy sources will
become quite expensive to produce. That will make the products from
that energy more expensive in dollar terms and that includes the
renewables.
Worse yet, the reserve data is subject to debate, witness the EIA's
projections which look worse each year as the reality of the situation
hits home. Sorry, the party is over.
> It is interesting that Lomberg is wrong and a skeptic because - pretty
> much as I do - he accepts that greenhouse gas emission reductions are
> necessary. It shows that the issue is not scientific - science is a
> threadbare justification for ever wilder claims of imminent doom. It
> is economics and politics.
The scientific part of AGW has just about been put to bed. Now, it;s
a question for the politicians and the people to decide.
> 'Limits to growth' ideas are dangerous bullshit that put many lives
> and legitimate human aspirations at risk. It matters a lot because we
> have already seen food riots as a result of the misallocation of
> global resources. But ecosocialism is not going to happen. Most of
> the world want cheaper and more abundant fuels - and cars, washing
> machines and air conditioners.
Limits to growth is reality. We live on a finite planet and there's
no obvious cheap energy source ready to replace the oil after the Peak
is seen. I'm an engineer too and have studied solar and wind
systems. They can be used to produce enough energy to keep things
going, but not enough to allow everybody on the planet to live like
the (formally) rich Americans who were able to waste oil and other
energy sources with abandon. The suburban lifestyles we think is
normal may pass away. Whether we find a rational path or return to
the days of the tooth and claw with the meanest knuckle draggers
running the show, only time will tell.
E. S.
---
James Annan
> Even such a seemingly simple question as to the rate of recent warming
> is subject to wide interpretation. Climate fluctuates strongly �
> principally in line with ENSO. Large interannual and decadal changes
> in surface temperature makes the interpretation of trend sensitive to
> both the end points and to the length of the record.
>
> Period Trend (degrees C/decade)
>
> 1900 - 2008 0.07
> 1945 � 2008 0.11
> 1958 � 2008 0.13
> 1979 � 1997 0.11
> 1976 � 2008 0.17
>
> Table 1: A quick comparison of periods and temperature trends
One interesting thing about that IMO is that despite the apparently wide
range of warming trends depending on endpoints, climate models manage to
match them all pretty well.
James
Phil Hays
> Also what is the concentration of CO2 in the air?? My understanding is that it is around 350 - 380 ppm?
See http://www.esrl.noaa.gov/gmd/ccgg/trends/co2_data_mlo.html
Current value is over 285 ppm. 1990 had about 350 ppm.
--
Phil Hays <phil...@ieee.org>
Phil Hays
> 'Limits to growth' ideas are dangerous bullshit
Really.
Energy use (or anything else) that grows at 3% a year doubles roughly
every 24 years.
Every hear of the chessboard and the prince?
The prince agreed to pay one grain of wheat on the first square of the
chessboard, and two grains on the next square, and four grains on the
third square, and continue doubling for all the squares of the chess
board. As soon as he agreed to this, the prince was bankrupt.
Is there enough wheat on the Earth today to pay for the 64th square? Do
calculate.
Let us change the problem a little bit, to four chessboards. Is there
enough wheat in the universe to pay the 256th square?
Let me help you out. 2^256 is about 10^77. The Universe has somewhere
around 10^80 atoms. A grain of wheat has about 10^23 atoms in it. So a
Universe that was nothing but wheat would have have about 10^57 grains
of wheat. A lot, to be sure, but not enough. Not even close to enough.
Even if the universe is all wheat.
Staying within known physics, (meaning no direct mass to energy
conversion or faster than light transportation), but allowing for fusion
energy, how many doublings of energy use before all the hydrogen in the
oceans has been converted to helium? Ignore the little problem of
getting rid of the waste heat.
Extracting uranium from ocean water might well be practical. If so,
nuclear energy could support current total energy usage for about 5
billion years, much longer than the Earth will be habitable. If energy
production from nuclear grew at 1%, how long would this amount of energy
last. Do ignore the little problem of the ocean needing time to be
recharged uranium content by rivers, and the other little problem of
getting rid of the waste heat.
Agree that there are limits?
Then let us get a little closer in time. Oil is somewhere between 1/4
and 1/2 drilled, pumped and burnt. We almost surely can't do another
doubling of oil production. What replaces oil? How?
--
Phil Hays <phil...@ieee.org>
Robbo
On Dec 28, 10:22 am, Eric Swanson <e_swan...@skybest.com> wrote:
> I must strongly disagree with what you wrote.
>
> On Dec 27, 4:22 pm, Robbo <rob...@robertellison.com.au> wrote:
>
> > Temperatures peaked (in every record of monthly temperature anomalies)
> > in the big El Nino of 1998. A wider significance of this is addressed
> > in the Tsonis et al and Swanson and Tsonis papers referenced - a
> > sudden climate shift in 1998/2001. Climate seen as a nonlinear
> > oscillator - a complex system in chaos theory. It seems possible that
> > the current cool mode will persist for another decade or two - until
> > the next multidecadal climate shift. New and startling science I know
> > - but as implacably logical as the Special Theory of
> > Relativity.
>
> There's another situation which may have impacted the climate of the
> late 1970's. It was called The Great Salinity Anomaly and was a large
> pool of relatively fresh water which circulated around the North
> Atlantic Sub Polar Gyre. About the same time, measurements indicated
> that the formation of bottom water in the Greenland Sea had ceased.
> That's like what may happen if the Thermohaline Circulation (THC) were
> to weaken or stop and most climate models coupled to dynamic ocean
> models predict that the THC will stop as the climate warms.
>
> http://www.whoi.edu/oceanus/viewArticle.do?id=2344&archives=true
>
You complain about Christy in 2003 - but use a 1996 (non peer
reviwed?) article on THC. If you had looked at the peer reviewed
science I referenced you would know that climate shifts - mini climate
tipping points - occur when global ocean states synchonise and then
shift into a different state.
THC is one of many nonlinear components of climate that has the
potential tobite us on the bum.
> One area in the Western Greenland Sea has exhibited changes associated
> with a reduction in THC in that area for the past two winters. The
> same pattern appears to be repeating so far this winter. Note the
> suggestion that the GSA was the result of increased flow of sea-ice
> out of the Arctic in 1967. That outflow has happened again these past
> few years. Only this time, it may not stop if the Arctic sea-ice
> melts away and opens the floodgates...
Short term characterisation of ocean elements that have obvious
decadal variability. THC in the Atlantic is one of those elements
that may result in an extreme nonlinear climate shift - morphing into
ice growth and an ice age over the next 10,000 years. Interesting -
but what do you want me to do about it? I already agree that we
should stop destabilising climate.
>
> > The current temperature trend is flat but any trend is masked by large
> > interannual variation mostly due to ENSO - making it impossible to be
> > definitive especially over shorter periods. Over longer periods of 50
> > or more years - the trend is about 0.1 degrees centigrade/decade.
> > Using the period of recent warming - 1976 to 1998 - includes two
> > periods of large climate fluctuation - the 1976/1977 'Great Pacific
> > Climate Shift' and the 1998/2001 climate shift - and distorts the true
> > rising trend. The other reference I cited was Thompson et al - who
> > filtered ENSO, volcanos and 'dynamically induced variability' from the
> > record. Reasonable estimates of the recent trend are about 0.1
> > degrees/decade.
>
> See above. The PDO may be associated with changes in the THC in the
> North Atlantic.
As above - the PDO and the IPO (Interdecadal Pacific Oscillation - a
Pacific wide phenomenon) - are probably an emergent global property of
climate as a dynamically variable complex system.
Australians are building liquefaction plants for conversion of brown
coal to fuel. The cost of mining brown coal (it doesn't have a
commercial value) in the Latrobe Vally is a couple of bucks a tonne -
and I hasten to add - with sequestration of production CO2 in Bass
Strait oil fields. It is commercially feasible at US$70/bbl and with
a coal price of $20/tonne.
I read yesterday that the Canadians are looking at nuclear power for
fuel extraction from their huge coaltar sand deposits - oh horror.
It is really only an interim solution to part of the problem. Keeping
suppliers honest while real alternatives are developed.
>
> > It is interesting that Lomberg is wrong and a skeptic because - pretty
> > much as I do - he accepts that greenhouse gas emission reductions are
> > necessary. It shows that the issue is not scientific - science is a
> > threadbare justification for ever wilder claims of imminent doom. It
> > is economics and politics.
>
> The scientific part of AGW has just about been put to bed. Now, it;s
> a question for the politicians and the people to decide.
I think that there is a great deal of scientific uncertainty.
However, as I said, it hardly matters for sensible public policy. What
matters is the most efective way of reducing greenhouse gas
emmissioons. Bring it on.
>
> > 'Limits to growth' ideas are dangerous bullshit that put many lives
> > and legitimate human aspirations at risk. It matters a lot because we
> > have already seen food riots as a result of the misallocation of
> > global resources. But ecosocialism is not going to happen. Most of
> > the world want cheaper and more abundant fuels - and cars, washing
> > machines and air conditioners.
>
> Limits to growth is reality. We live on a finite planet and there's
> no obvious cheap energy source ready to replace the oil after the Peak
> is seen. I'm an engineer too and have studied solar and wind
> systems. They can be used to produce enough energy to keep things
> going, but not enough to allow everybody on the planet to live like
> the (formally) rich Americans who were able to waste oil and other
> energy sources with abandon. The suburban lifestyles we think is
> normal may pass away. Whether we find a rational path or return to
> the days of the tooth and claw with the meanest knuckle draggers
> running the show, only time will tell.
>
I have actually installed a solar voltaic system in my inlaws grass
hut on the Island of Misima. Bloody expensive way to run a few 12V
lamps, a DVD and a battery charger. A range of solutions is good - no
silver bullet. 4th generation nuclear - molten salt or pebble bed -
has to be an option for all of the cost, non-proliferation and waste
advantages it brings. Cheap power is all that is needed and
everything is possible including space colonisation for gods sake. If
you are an engineer - engineers (like Barack Obama) say yes we can.
I think the era of the meanest knuckle draggers was last century in
the operation of all of the socialist states. Dismantling democratic
and capititalist structures creates a power vacuumn in which scum
rises to the top. All of the best intentions of people from Shaw to
Einstein ending in the murder of hundreds of millions of people. To
me the rational path is economic growth and development and stable
democracies.
> E. S.
> ---
hgerh...@yahoo.co.uk
> other sources of hydrocarbons which can be used to make liquid fuels,
> but the Energy Return On Energy Invested (EROEI) for all these sources
> is less than that for the easy to get at oil we so carelessly burned.
EROEI seems like a nice concept, but unless the Energy In is truely
equivalent to the Energy out and more is used than produced, EROEI is
surprisingly insignificant.
> Tar Sands are a prime example, as natural gas is used to separate the
> dense tar from the mixture.
Why are oil sands commercial? The Energy In is mostly low temperature
(and very low value) process heat, the energy Energy out is high value
transportation fuels.
What's the EROEI of a Gas to Liquids plant? Is input greater than
output here?
You can have 100 kWh of oil sands removed from the earth with 50 kWh
of natural gas. Some people will claim this is an EROEI of 2:1. Yet,
with 100 kWh of natural gas input to a GTL plant and 50 kWh of
transportation fuel output, we might get half the transportation fuel
output for twice the natural gas input, but some people will claim the
EROEI is 5:1 or higher for the GTL route because little energy got
used to extract the natural gas.
> They can be used to produce enough energy to keep things
> going, but not enough to allow everybody on the planet to live like
> the (formally) rich Americans who were able to waste oil and other
> energy sources with abandon.
Well, the IPCC scenarios do as far as I know assume that the average
world citizen in 2100 will be twice as rich as the average American
was in the year 2000.
Robbo
averaging over periods of 100 years or more. They are claimed to be
accurate - although Don Easterbrook has written abour the potential
for small errors in radiative forcing estimates, for instance, to
propagate through the calculations to produce uncertainty bounds at
2100 of +/- 17 degrees C. Weather on the other is said to be an
'initial value' problem. Detailed knoweledge of initial conditions is
required to define the evolution of weather over up to 10 days with
reasonable accuraccy. After that calcultions diverge from reality.
There is an intermediate timeframe of slow oceanic changes on
interannual to multidecadal timeframes. This in the interval where
climate needs to be approached as an initial value problem like
weather. No one has ever said that GCM are any good at all at the
slow climate processes - which is an initial value problem. That is -
climate models can and do diverge from reality over up to a couple of
decades without being a theoretical problem.
On Dec 28, 3:24 pm, James Annan <james.an...@gmail.com> wrote:
> Robbo wrote:
> > Even such a seemingly simple question as to the rate of recent warming
> > is subject to wide interpretation. Climate fluctuates strongly
> > principally in line with ENSO. Large interannual and decadal changes
> > in surface temperature makes the interpretation of trend sensitive to
> > both the end points and to the length of the record.
>
> > Period Trend (degrees C/decade)
>
> > 1900 - 2008 0.07
> > 1945 2008 0.11
> > 1958 2008 0.13
> > 1979 1997 0.11
> > 1976 2008 0.17
Robbo
constrained by carrying capacity. We are human - we have obviously
increased the carrying capacity for ourselves a 1000 fold or more and
we are only just at the beginning of bigger, better and many more
technological advances. Thorium in fast neutron reactors would seem
to be an obvious candidate for a fuel of the coming centuries. Let’s
solve one problem at a time. Just when we should be confident - you
want to throw in the towel?
There are billions of people now in the direst poverty. We are
nowhere near filling the universe with wheat. At any rate - economic
growth is not necessarily about physical resource inputs. It includes
medicine, education, art, poetry, music, philosophy, mathematics and
technological innovation.
> Phil Hays <phil_h...@ieee.org>
Alastair
On Dec 28, 12:11 pm, Robbo <rob...@robertellison.com.au> wrote:
>
> There are billions of people now in the direst poverty. We are
> nowhere near filling the universe with wheat.
But we are near to filling the surface of the Earth with wheat
fields. When we finally destroy the remaining tropical jungles for
farming land, not only will there be no new land to more food, we will
also have damaged the climate system irrevocably. Without tree cover
the Amazon will become a desert, and also release even more CO2 into
an climate system that is about to collapse.
Think about it!
Cheers, Alastair.
Phil Hays
> The model to be used is the population model - exponential growth
> constrained by carrying capacity. We are human - we have obviously
> increased the carrying capacity for ourselves a 1000 fold or more and
> we are only just at the beginning of bigger, better and many more
> technological advances. Thorium in fast neutron reactors would seem
> to be an obvious candidate for a fuel of the coming centuries. Let’s
> solve one problem at a time. Just when we should be confident - you
> want to throw in the towel?
>
> There are billions of people now in the direst poverty. We are
> nowhere near filling the universe with wheat. At any rate - economic
> growth is not necessarily about physical resource inputs. It includes
> medicine, education, art, poetry, music, philosophy, mathematics and
> technological innovation.
So then you do agree that there are limits to growth? Limits that we
will hit long before we fill the universe with wheat? Filling the
universe with wheat would take about 1400 years at 3% growth. Not to
mention cheap FTL transportation, converting a lot of the hydrogen and
helium to carbon and assorted other improbable and/or impossible
technologies. Are we not just discussing what the limits are?
There is very roughly four times as much thorium as uranium. That would
allow for two additional doublings, or just 48 more years at 3% growth,
or two more squares on the chessboard. Ignoring little details such as
waste heat. Growth isn't sustainable. There are limits to growth.
Thorium could also allow for about four times the current energy usage
for five billion years. Use of wind and solar energy could double or
triple this again, allowing for more than eight times current energy
usage for the expected life of the planet. The hard part is how do we
avoid the climate disaster from burning fossil fuels (and several other
potential disasters) and transition to a static resource use, static
population, sustainable economy? Or do we crash, as exponential growth
exceeds carrying capacity?
BTW: A thorium fueled fast neutron reactor seems to me to be a very very
odd choice. Thorium, unlike uranium, doesn't need fast neutrons to have
a breeding ratio greater than one in a reactor. Both light water cooled
and heavy water cooled reactors have been operated with thorium fuel
rods, and have been shown to produce more fuel (U233) than consumed.
Fast neutron reactors are more complex and expensive, but have the
advantage of being able to breed more fuel (plutonium) from uranium
(U238) than they consume (plutonium and U235). Why used a more expensive
and complex reactor with the advantage of being able to breed fuel from
uranium to breed fuel from thorium when cheaper and more reliable
reactors can do that? I don't understand at all. Now, my interest in
nuclear power comes from the fact that it seem to be a requirement to
solve the global warming issue. I'm no expert on the details of nuclear
power, so perhaps someone can point me to a discussion explaining this
choice.
--
Phil Hays <phil...@ieee.org>
Phil Hays
Yea, I'm talking to myself.
> BTW: A thorium fueled fast neutron reactor seems to me to be a very very
> odd choice. Thorium, unlike uranium, doesn't need fast neutrons to have
> a breeding ratio greater than one in a reactor. Both light water cooled
> and heavy water cooled reactors have been operated with thorium fuel
> rods, and have been shown to produce more fuel (U233) than consumed.
> Fast neutron reactors are more complex and expensive, but have the
> advantage of being able to breed more fuel (plutonium) from uranium
> (U238) than they consume (plutonium and U235). Why used a more expensive
> and complex reactor with the advantage of being able to breed fuel from
> uranium to breed fuel from thorium when cheaper and more reliable
> reactors can do that? I don't understand at all. Now, my interest in
> nuclear power comes from the fact that it seem to be a requirement to
> solve the global warming issue. I'm no expert on the details of nuclear
> power, so perhaps someone can point me to a discussion explaining this
> choice.
Some quality time with Google let me find an answer to my question.
Light water thorium breeder reactors have breeding ratios only a little
over 1. The Shippingport reactor, for example, ran at a breeding ratio
1.01. As such it would require reprocessing to operate. Heavy water
thorium breeder reactors are somewhat better, and can operate with only
thorium fuel after startup, allowing reprocessing to be delayed for
decades or even centuries to allow for most of the very radioactive
elements to decay. Thorium breeders of any sort need to be fueled during
startup with a mix of thorium and either enriched uranium or plutonium.
For India, with little uranium resources and having had strict limits on
importing uranium, and with massive thorium resources, this poses a
startup problem for thorium based nuclear power. So India has designed
and is constructing fast neutron breeder reactors mostly fueled with
thorium to produce plutonium from India's very limited uranium to more
quickly start the thorium fueled power cycle. Such fast neutron reactors
would be not needed, or even useful in a steady state, or with the
abundant and cheap enriched uranium outside India. The limits on
importing uranium were imposed to limit/punish Indian nuclear weapon
production.
Longer term, limits on uranium might be probably counterproductive. To
reduce the risk of U233 produced by a thorium breeder reactor being used
for nuclear weapons, the fuel mix could include some depleted or natural
uranium, which can't be chemically separated from the U233, but could
only be separated by isotopic enrichment. The reprocessed fuel from a
thorium only breeder reactor would be more usable for nuclear weapons
than reprocessed fuel from a thorium/uranium fueled breeder reactor.
--
Phil Hays <phil...@ieee.org>
Robbo
http://thoriumenergy.blogspot.com/2009/04/thorium-molten-salt-reactor-launching.html
I understand that gen 3 reactors utilise about 3% of the energy
content of their uranium fuel source - leaving behind a radiation
legacy for hundreds of thousands of years. Gen 4 reactors are 98%
efficient, can use a variety of fuel sources including recycled gen 1,
2 and 3 waste, recycled weapons plutonium and thorium - so really it
is a multiple fuel platform rahter than limited to thorium. The waste
is safe enough after a couple of hundred years and can be made
proliferation resistant. I should perhaps have called it a high
temperature reactor rather than confuse the issue (with conventional
breeder reactors) by calling it a fast neutron reactor.
The low pressure reactors do not require expensive containment
structures - so should be a lot cheaper. They are designed to be
'walk away' facilities using passive safety features - walk away and
they cool down not melt down. There is no need for multiply redundant
and expensive cooling systems. They are designed to be modular -
modules can be manufactured in a factory and transported anywhere.
They are operated at high temperatures facilitating hydrogen
production (which can be used directly or converted to liquid fuels)
from hydrolysis of water.
Commercial 4th generation nuclear reactors are some 20 years off still
but there are many places in the world where 3rd gen reactors are cost
effective. Why not utilise existing technology in the meantime,
generate the start up materials for rapid deployment and deploy the
next gen technology ASAP. I have long argued that Australia needs to
get heavily into the processing, reprocessing and storage of nuclear
materials - for all sorts of reasoins. How can we supply nuclear
mterials and morally not? We could continue burning coal locally for
a while, offett all our emmissions and then some and make a profit.
One of the potentially useful features of the newer technology is that
it is modular and can be scaled up or down as required. They could be
used, for instance, to replace conventional furnaces in existing coal
powered generators. They could be used in situations in the developing
world where a GigaWatt plant is overkill.
You misunderstand me - while there may be population constraints at
any one time the human species can move the goalposts with
technology. The limit to growth is human ingenuity and I believe
that is true yesterday, tomorrow, this century and, with a little
flight of fancy, for the unlimited human destiny over the next 5
billion years amongst the stars. As we all know – there is no limit to
either human ingenuity or human stupidity.
‘Heat Pollution. Over the next millennium and for the rest of human
history, earth's major environmental problem will be warming due not
to greenhouse gases but rather to increased waste heat from non-solar
energy (initially petrochemical, but then fusion). The problem emerges
when a world population in the high tens or low hundreds of billions
all enjoy an energy budget equivalent to the industrialized West in
2000. All the waste heat from all the energy uses adds up, and the
laws of thermodynamics guarantee that energy use always creates heat
exhaust. Heat pollution will have to be managed to prevent a runaway
greenhouse effect like on Venus.’
Source: http://humanknowledge.net/
Threadbare scientific justification for wild scenarios? Back of the
envelope calculations for a system that not even the latest
supercomputers can handle? (Researchers are calling for 1000 times
current computing power just to handle cloud dynamics.) Give me a
break.
Several other possible disasters this century? There are a lot of
people out there who need therapy. Not just an hour a week on a couch
but a team of highly trained specialists working around the clock
(joke). Inventing problems is too depressing - solving problems is a
better option. Most people have given up even listening to
environmental Cassandras.
There is no possibility that the human population will reach even 10
billion. Current long range projections show population peaking in
the middle of this century at about 9 billion. There is one way to
reduce this number – accelerated global economic development.
http://www.un.org/esa/population/publications/longrange2/WorldPop2300final.pdf
Economies are a human construct. They are also a complex system in
the terms of dynamically complex systems theory. They seem to need to
grow to be minimally stable (no one ever claimed that capitalism is
perfect). Heavy handed government intervention in global economies
has very significant risks for us all as we have seen time and time
again. However, if production is sustainable - there is theoretically
no need to limit economic growth - and absolutely not as yet I believe
even if systems are not yet sustainable. There is a great human need
for continued development over this century. We simply need to
engineer greener systems.
Over the next millennium – we will need to start moving off planet
because populations either grow or decline. (Populations are dynamic
and complex.) Perhaps using instantaneous quantum teleportation for
FTL travel? Quantum teleportation is an actual working technology
based on quantum entanglement - though not of course workable for
human star travel - yet. (Please - this latter is just a fun idea and
I don't need to enter into a debate.)
> Phil Hays <phil_h...@ieee.org>
Robbo
20th century temps - that is they all reproduce temps pretty well and
would generally be considered a failure if they couldn't be validated
in this way. The projections to 2100 however have temperature
increasing from 1 to 10 degrees (or more in some very extreme cases).
This is because the models all rely more or less on judgement and
approximation. That is they are heuristic tools - rules of thumb -
rather than having a unique solution. The solution is assumed to fall
somewhere in the range of estimates.
The method is unexceptional but a 'reality check' is commonly applied
to heuristic solutions. In this case we have a simple check already
alluded to. For an increase of 80 ppmv of CO2 since the mid 1940's
there is an associated 0.6 degree temperature rise. We are at about
386 ppmv and expected (BAU) to increase to 590 ppmv by 2100. So an
additional 200 ppmv giving a 1.5 degrees rise? Within the solution
space. Assuming there is a little more heating of 0.5 degrees 'in the
pipeline' (according to Jim Hanson) - say a maximum of 3 degrees by
2100.
I am not hugely relaxed about that - and we risk (as climate is a
nonlinear oscillator) either snowball or hothouse earth. But take ten
deep breaths and start figuring how to get off the BAU trajectory
without dismantling global economic systems.
On Dec 28, 3:24 pm, James Annan <james.an...@gmail.com> wrote:
> Robbo wrote:
> > Even such a seemingly simple question as to the rate of recent warming
> > is subject to wide interpretation. Climate fluctuates strongly
> > principally in line with ENSO. Large interannual and decadal changes
> > in surface temperature makes the interpretation of trend sensitive to
> > both the end points and to the length of the record.
>
> > Period Trend (degrees C/decade)
>
> > 1900 - 2008 0.07
> > 1945 2008 0.11
> > 1958 2008 0.13
> > 1979 1997 0.11
> > 1976 2008 0.17
Eric Swanson
I complained about your use of Christy's old PR data. You ignored the
fact that his latest data shows more warming. You commented about the
recent work from Swanson and Tsonis regarding the so-called Pacific
Decadal Oscillation and I pointed out that the Pacific is linked to
the North Atlantic thru the THC. The analysis of Swanson and Tsonis
is rather speculative and based on correlations. As anyone in science
knows, correlation is not causation.
> > One area in the Western Greenland Sea has exhibited changes associated
> > with a reduction in THC in that area for the past two winters. The
> > same pattern appears to be repeating so far this winter. Note the
> > suggestion that the GSA was the result of increased flow of sea-ice
> > out of the Arctic in 1967. That outflow has happened again these past
> > few years. Only this time, it may not stop if the Arctic sea-ice
> > melts away and opens the floodgates...
>
> Short term characterisation of ocean elements that have obvious
> decadal variability. THC in the Atlantic is one of those elements
> that may result in an extreme nonlinear climate shift - morphing into
> ice growth and an ice age over the next 10,000 years. Interesting -
> but what do you want me to do about it? I already agree that we
> should stop destabilising climate.
Again, the change to Ice Age conditions may happen much sooner than
your projected 10,000 years. At the start of the present period of
Ice Ages some 3 million years BP, it appears that the North Atlantic
and the Arctic were much warmer than today. It's easy to speculate
that our increasingly warm conditions could bring on another period of
very cold conditions, i.e., a return of a real Ice Age.
http://micropress.org/stratigraphy/papers/Stratigraphy_6_4_265-275.pdf
> > > The current temperature trend is flat but any trend is masked by large
> > > interannual variation mostly due to ENSO - making it impossible to be
> > > definitive especially over shorter periods. Over longer periods of 50
> > > or more years - the trend is about 0.1 degrees centigrade/decade.
> > > Using the period of recent warming - 1976 to 1998 - includes two
> > > periods of large climate fluctuation - the 1976/1977 'Great Pacific
> > > Climate Shift' and the 1998/2001 climate shift - and distorts the true
> > > rising trend. The other reference I cited was Thompson et al - who
> > > filtered ENSO, volcanos and 'dynamically induced variability' from the
> > > record. Reasonable estimates of the recent trend are about 0.1
> > > degrees/decade.
>
> > See above. The PDO may be associated with changes in the THC in the
> > North Atlantic.
>
> As above - the PDO and the IPO (Interdecadal Pacific Oscillation - a
> Pacific wide phenomenon) - are probably an emergent global property of
> climate as a dynamically variable complex system.
We know the THC varies and I pointed to data that showed it weakened
considerably during the 1970's. The PDO variations may not explain
the temperature changes, both may be caused by some other aspect of
climate. I think it's just as reasonable to conclude that the
oscillations in the PDO may have been the result of changes in the
THC. Chicken or Egg, anyone?
E. S.
----
Alastair
> I am not hugely relaxed about that - and we risk (as climate is a
> nonlinear oscillator) either snowball or hothouse earth. But take ten
> deep breaths and start figuring how to get off the BAU trajectory
> without dismantling global economic systems.
Well, we have to dismantle the global economic system or else. But
neither the politicians nor the scientists will admit that. The Stern
Report was just a load of optimistic platitudes. But until people
start listening to Lovelock and Hansen then we will just continue to
sleepwalk towards the edge of a cliff.
Cheers, Alastair.
Phil Hays
> You misunderstand me - while there may be population constraints at
> any one time the human species can move the goalposts with
> technology. The limit to growth is human ingenuity and I believe
> that is true yesterday, tomorrow, this century and, with a little
> flight of fancy, for the unlimited human destiny over the next 5
> billion years amongst the stars. As we all know – there is no limit to
> either human ingenuity or human stupidity.
In short, you believe in magic.
I don't believe in magic. It seems to me that the physical world has
limits that ingenuity can't alter. Or in other words, there are limits
to ingenuity.
There are physical limits to what can be done. We might not understand
them completely, but what ever these limits are, they can't be changed
by anything that we might do.
--
Phil Hays <phil...@ieee.org>
Don Libby
Newsgroups: gmane.science.general.global-change
To: <global...@googlegroups.com>
Sent: Tuesday, December 29, 2009 11:40 AM
Subject: [Global Change: 3359] Re: AGW Scientifc Certainty
On Mon, 2009-12-28 at 16:17 -0800, Robbo wrote:
>> You misunderstand me - while there may be population constraints at
>> any one time the human species can move the goalposts with
>> technology. The limit to growth is human ingenuity and I believe
>> that is true yesterday, tomorrow, this century and, with a little
>> flight of fancy, for the unlimited human destiny over the next 5
>> billion years amongst the stars. As we all know � there is no limit to
>> either human ingenuity or human stupidity.
>
>In short, you believe in magic.
>
>I don't believe in magic. It seems to me that the physical world has
>limits that ingenuity can't alter. Or in other words, there are limits
>to ingenuity.
>
>There are physical limits to what can be done. We might not understand
>them completely, but what ever these limits are, they can't be changed
>by anything that we might do.
I think you're talking past each other. Phil is right, for example,
gravitation limits our ability to levitate by the power of mental effort
alone, and on the other hand, it is possible to engineer systems that allow
us to levitate (we call them helicopters).
When it comes to "earth's carrying capacity", it has been theorized that
10^12 people could be sustained indefinitely without breaking any physical
laws, but few would want to live the ant-like existence it would require.
For present purposes, discussions of limits should be bounded by the present
population and the forseeable future: how do we engineer systems to sustain
10^10 people for 10^2 years with high and rising living standards and
minimal environmental damage?
I think IPCC scenarios A1T and B1 make a pretty good starting point for
discussions about what to do next.
-dl
Robbo
based on correlation. They used a relatively new network approach to
analysing complex systems. They used 4 ocean/climate indices - the
Pacific Decadal Oscillation (PDO), the North Atlantic Oscillation
(NAO), the El Nin˜o/Southern Oscillation(ENSO), and the North Pacific
Oscillation (NPO) and show that climate behaves on multidecadal
timeframes as you would expect it to - as a complex system in terms of
complex systems theory. Climate bahaves as a forced nonlinear
oscillator at scales frome ENSO to ice ages and beyond. This supports
your argument rather than otherwise. Small changes in initial
conditions leading to large changes in climate.
See for instnce - Slowing down as an early warning signal for abrupt
climate change - Vasilis Dakos*, Marten Scheffer*†, Egbert H. van
Nes*, Victor Brovkin‡§, Vladimir Petoukhov‡, and Hermann Held‡:
www.pnas.org/cgi/doi/10.1073/pnas.0802430105
The 2007 paper from Tsonis et al- A new dynamical mechanism for major
climate shifts - is the more important in giving the background ideas.
The 2009 Swanson and Tsonis paper is an update. There is no such thing
as simple causality in climate - climate has many degrees of freedom
that are dynamically interactive. There is no chicken and no egg -
just a dynamically evolving system that includes both the PDO and THC
as well as many other factors.
The 10,000 years was eyeballed from the Vostok ice core data. Temp
changes either way of up to 10 degrees over a few thousand years. The
Bermuda-Labrador Basin Transport Index is down since early this
century - there is a nice collection of ocean/climate data at
http://ioc-goos-oopc.org/state_of_the_ocean/sub/berm_lab_trans.php -
and it is très amusant to speculate that early in 1998 might have been
the warmest point in the next 100,000 years. It is overwhelmingly
probable that an ice age is around the next climate
corner.
That gives me an idea - use autocorrelation minima (slowing down in
complex systems theory) on the Vostok data to predict initiation of
the next ice age. I may be gone for some time.
Eric Swanson
On Dec 29, 4:18 pm, Robbo <rob...@robertellison.com.au> wrote:
> Tsonis et al (2007) and Swanson and Tsonis (2009) results are not
> based on correlation. They used a relatively new network approach to
> analysing complex systems. They used 4 ocean/climate indices - the
> Pacific Decadal Oscillation (PDO), the North Atlantic Oscillation
> (NAO), the El Nin˜o/Southern Oscillation(ENSO), and the North Pacific
> Oscillation (NPO) and show that climate behaves on multidecadal
> timeframes as you would expect it to - as a complex system in terms of
> complex systems theory. Climate bahaves as a forced nonlinear
> oscillator at scales frome ENSO to ice ages and beyond. This supports
> your argument rather than otherwise. Small changes in initial
> conditions leading to large changes in climate.
>
> See for instnce - Slowing down as an early warning signal for abrupt
> climate change - Vasilis Dakos*, Marten Scheffer*†, Egbert H. van
> Nes*, Victor Brovkin‡§, Vladimir Petoukhov‡, and Hermann Held‡:www.pnas.org/cgi/doi/10.1073/pnas.0802430105
>
> The 2007 paper from Tsonis et al- A new dynamical mechanism for major
> climate shifts - is the more important in giving the background ideas.
> The 2009 Swanson and Tsonis paper is an update. There is no such thing
> as simple causality in climate - climate has many degrees of freedom
> that are dynamically interactive. There is no chicken and no egg -
> just a dynamically evolving system that includes both the PDO and THC
> as well as many other factors.
The system is highly damped, else the entire climate system would
"ring" with a harmonic of the major driving force, the yearly
insolation cycle, would it not? Remember that the forces must balance
the energy flows thru the system, sunlight in, IR out and the IR
emissions are a function of T^4 (mol). That there is an obvious
oscillation in the ENSO cycle does not imply that there are other,
longer term periods of oscillation (not fixed period cycles). It's
often claimed that the solar sunspot cycle shows up in the weather
data, but finding the longer term frequencies, such as the Gleissberg
cycle, is a subject of continual debate.
> The 10,000 years was eyeballed from the Vostok ice core data. Temp
> changes either way of up to 10 degrees over a few thousand years. The
> Bermuda-Labrador Basin Transport Index is down since early this
> century - there is a nice collection of ocean/climate data athttp://ioc-goos-oopc.org/state_of_the_ocean/sub/berm_lab_trans.php-
> and it is très amusant to speculate that early in 1998 might have been
> the warmest point in the next 100,000 years. It is overwhelmingly
> probable that an ice age is around the next climate
> corner.
>
> That gives me an idea - use autocorrelation minima (slowing down in
> complex systems theory) on the Vostok data to predict initiation of
> the next ice age. I may be gone for some time.
Before you go off on a wild goose chase, here's some food for thought:
http://www.aip.org/history/climate/cycles.htm
E. S.
---
James Annan
> Let me hark back to GCM for a minute. The models all are tuned to
> 20th century temps - that is they all reproduce temps pretty well and
> would generally be considered a failure if they couldn't be validated
> in this way. The projections to 2100 however have temperature
> increasing from 1 to 10 degrees (or more in some very extreme cases).
Um, it's more like 1.5 to 6, and that range covers the different
emissions scenarios, which are not really anything to do with climate
science. There has been a bit of wild stuff from MIT suggesting more
rapid warming, but this does not use GCMs and I for one don't believe it
(and have sound scientific reasons to back that up, based on what I know
of their methods).
> The method is unexceptional but a 'reality check' is commonly applied
> to heuristic solutions. In this case we have a simple check already
> alluded to. For an increase of 80 ppmv of CO2 since the mid 1940's
> there is an associated 0.6 degree temperature rise. We are at about
> 386 ppmv and expected (BAU) to increase to 590 ppmv by 2100. So an
> additional 200 ppmv giving a 1.5 degrees rise? Within the solution
> space. Assuming there is a little more heating of 0.5 degrees 'in the
> pipeline' (according to Jim Hanson) - say a maximum of 3 degrees by
> 2100.
This would be reasonable if it was known that CO2 was the only
significant forcing. However, sulphate aerosols have very likely offset
a significant proportion of the warming that would otherwise have
occurred. Hence the upper limit of plausible future warming is rather
higher than your value.
There is some recent evidence that the aerosol effect is towards the low
end of previous estimates, which would be good news, but I don't think
it is yet universally accepted. I do think it's plausible we would see
only about 2C more warming in this century even if emissions continue to
rise steadily (eg linearly extrapolating the recent rise in forcing),
but I wouldn't want to bet the farm on it.
James
Alastair
On Dec 30, 2:20 am, James Annan <james.an...@gmail.com> wrote:
> it is yet universally accepted. I do think it's plausible we would see
> only about 2C more warming in this century even if emissions continue to
> rise steadily (eg linearly extrapolating the recent rise in forcing),
> but I wouldn't want to bet the farm on it.
Using my arithmetic (check?), CO2 increased at Mauna Loa by 0.850 ppm
per year in the ten years 1960-69, and by 1.875 in the ten years
1999-2008.
http://www.esrl.noaa.gov/gmd/ccgg/trends/
That is more than doubling of the rate of increase in 50 years is not
what I would call a linear, and would mean close to 3 times the pre-
industrial level by 2100.
Cheers, Alastair.
James Annan
work out the forcing?
James
2009/12/31 Alastair <a...@abmcdonald.freeserve.co.uk>:
Alastair
On Dec 31, 12:06 pm, James Annan <james.an...@gmail.com> wrote:
> And what happens if you divide the total by 280 and take the log to
> work out the forcing?
>
> James
I was leaving that to you :-) You are the mathematician!
but in case you haven't noticed the glaciers, Antarctic ice and Arctic
sea ice are all melting much faster than your log of the forcing would
imply.
Cheers, Alastair.
Robbo
http://www.ig.utexas.edu/people/staff/charles/uncertainties_in_model_predictio.htm
- not simply carbon trajectories.
Climate seen as a dynamically complex system is theoretically
determinant (as an initial value problem) but practically incalculable
and I doubt that there is any value in these 'boundary value'
projections at all. Complex systems theory - and real world data -
suggests that abrupt change is the norm for climate at all timescales
from ENSO to ice ages and beyond. Theory suggests that small changes
in initial conditions (e.g. greenhouse gases) trigger climate
fluctuation with climate then settling into a new state. Climate
could be either warmer of cooler in 100 years and there is absolutely
no way of meaningfully predicting what it will be.
Tsonis et al (2007) – (https://pantherfile.uwm.edu/kravtsov/www/
downloads/GRL-Tsonis.pdf) used a relatively new network approach to
analysing complex systems. They used 4 ocean/climate indices - the
Pacific Decadal Oscillation (PDO), the North Atlantic Oscillation
(NAO), the El Niño/Southern Oscillation(ENSO), and the North Pacific
Oscillation (NPO) and show that climate behaves on multidecadal
timeframes as you would expect it to - as a complex system in terms of
complex systems theory. Major climate shifts occurred around 1910, the
mid 1940’s, the mid 1970’s and 1998/2001.
While complexity theory shows the futility of ambitious projections of
average future climate – it suggests that there are other ways of
approaching the problem. I have been reading a recent article by
Vasilis Dakos and colleagues:
‘Slowing down as an early warning signal for abrupt climate change
Abstract
In the Earth's history, periods of relatively stable climate have
often been interrupted by sharp transitions to a contrasting state.
One explanation for such events of abrupt change is that they happened
when the earth system reached a critical tipping point. However, this
remains hard to prove for events in the remote past, and it is even
more difficult to predict if and when we might reach a tipping point
for abrupt climate change in the future. Here, we analyze eight
ancient abrupt climate shifts and show that they were all preceded by
a characteristic slowing down of the fluctuations starting well before
the actual shift. Such slowing down, measured as increased
autocorrelation, can be mathematically shown to be a hallmark of
tipping points. Therefore, our results imply independent empirical
evidence for the idea that past abrupt shifts were associated with the
passing of critical thresholds. Because the mechanism causing slowing
down is fundamentally inherent to tipping points, it follows that our
way to detect slowing down might be used as a universal early warning
signal for upcoming catastrophic change. Because tipping points in
ecosystems and other complex systems are notoriously hard to predict
in other ways, this is a promising perspective.’
– the article is downloadable from PNAS.
It occurred to me that it might be possible to apply the
autocorrelation technique of Schaffer et al to ENSO and Vostok ice
core data and take at stab at predicting ENSO and ice ages.
Complex systems theory suggests that abrupt climate change is the norm
at any time in the history of the planet. Climate is complex and
dynamic and fluctuates wildly between extremes on all sorts of
timescales.
Any projection - including my own I am afraid - is nonsense.
Alastair
weather, then it has the shape of an annual cycle. We cannot of course
tell precisely where it will be next year. However it may be
possible to determine where the tipping points are that would cause
the atrractor to be changed to another. Changing the CO2 concentration
is one of those determining factors. But how it will affect the
attractor is an unknown.
Cheers, Alastair.
On Jan 1, 4:34 am, Robbo <rob...@robertellison.com.au> wrote:
> There is a wide range of results from climate models -http://www.ig.utexas.edu/people/staff/charles/uncertainties_in_model_...
> > Cheers, Alastair.- Hide quoted text -
>
> - Show quoted text -
john fernbach
On Dec 27 2009, 4:22 pm, Robbo <rob...@robertellison.com.au> wrote:
> Temperatures peaked (in every record of monthly temperature anomalies)
> in the big El Nino of 1998. A wider significance of this is addressed
> in the Tsonis et al and Swanson and Tsonis papers referenced - a
> sudden climate shift in 1998/2001. Climate seen as a nonlinear
> oscillator - a complex system in chaos theory. It seems possible that
> the current cool mode will persist for another decade or two - until
> the next multidecadal climate shift. New and startling science I know
> - but as implacably logical as the Special Theory of
> Relativity.
>
> The current temperature trend is flat but any trend is masked by large
> interannual variation mostly due to ENSO - making it impossible to be
> definitive especially over shorter periods. Over longer periods of 50
> or more years - the trend is about 0.1 degrees centigrade/decade.
> Using the period of recent warming - 1976 to 1998 - includes two
> periods of large climate fluctuation - the 1976/1977 'Great Pacific
> Climate Shift' and the 1998/2001 climate shift - and distorts the true
> rising trend. The other reference I cited was Thompson et al - who
> filtered ENSO, volcanos and 'dynamically induced variability' from the
> record. Reasonable estimates of the recent trend are about 0.1
> degrees/decade.
>
> My post is a little disjointed - I started writing about scientific
> uncertainty. But I think that greenhouse gas emissions need to be
> reduced ASAP. The policy question is what the most effective way of
> doing that is. My belief is that continued economic growth and the
> technological path is the way to go. There are numbers of options for
> power and transport. Cheap solar photovoltaic would be fantastic for
> the developing world. Solar accumulators, high temperature nuclear
> reactors, energy efficiency - literally dozens of emerging
> technologies. Peak oil is a nonsense - there are many alternative
> sources of carbon. Including coal gasification and liquefaction, tar
> sands and shale oil - literally a thousand years of fuel supplies.
> More exotic means of fuel production include high temperature
> hydrolosis to create hydrogen which can then be combined with carbon
> dioxide to produce liquid fuels.
>
> It is interesting that Lomberg is wrong and a skeptic because - pretty
> much as I do - he accepts that greenhouse gas emission reductions are
> necessary. It shows that the issue is not scientific - science is a
> threadbare justification for ever wilder claims of imminent doom. It
> is economics and politics.
>
> 'Limits to growth' ideas are dangerous bullshit that put many lives
> and legitimate human aspirations at risk. It matters a lot because we
> have already seen food riots as a result of the misallocation of
> global resources. But ecosocialism is not going to happen. Most of
> the world want cheaper and more abundant fuels - and cars, washing
> machines and air conditioners.
Does the fact that "most of the world want cheaper and more abundant
fuels" by itself, demonstrate that "limits to growth" ideas are
bullshit?
Or could the Rolling Stones be correct?
Could it be that "you can't always get what you want," no matter how
many people want it?
Please excuse a rude interjection from someone who's not a
professional scientist.
But I just don't see why the popularity of perpetual economic growth
supported by ever-increasing energy supplies is going to make either
perpetual growth or ever-increasing energy supplies possible.
If perpetually growing use of energy and a perpetually expanding
global GDP are technically & logically feasible, I'd like to see this
demonstrated. I'd rather not take it on faith.
>
> On Dec 28, 1:40 am, "Nolin, Kenneth M." <KMNo...@fbd.com> wrote:
>
>
>
> > I thought we had global cooling for the last 10 - 11 years. So how can you say there is an increase? I don't understand. Also what is the concentration of CO2 in the air?? My understanding is that it is around 350 - 380 ppm?
>
> > -----Original Message-----
> > From: global...@googlegroups.com [mailto:global...@googlegroups.com] On Behalf Of Robbo
> > Sent: Saturday, December 26, 2009 7:09 PM
> > To: globalchange
> > Subject: [Global Change: 3332] Re: AGW Scientifc Certainty
>
> > I used the CRU dataset for calculating trend over the specified
> > periods. The critical point - whatever source is used - is that start
> > and end points influence trend estimation because of large interannual
> > variation that is mostly due to ENSO. I believe that the trend
> > estimated by Kyle Swanson this year at realclimate and by Thompson et
> > al 2009 - about 0.08 to 0.12 degrees C/decade is about right. This
> > seems to make the IPCC prediction of a continuing increase over the
> > next few decades of 0.2 degrees C unlikely along with the higher model
> > projections(up to 6 degrees) this century.
>
> > I do not understand what your point is? That the rate of recent
> > warming is 0.13 degrees C/decade?
>
> > All of the various methodologies have evolved over the years as
> > methods improve - what I see is that the results from all of the
> > methodologies are converging as they should with a better
> > understanding.
>
> > To my mind - the problem is no longer scientific but what policy
> > response can best and most quickly achieve reductions in emissions. I
> > agree with the Lomberg approach. I will happily write to Inhoffe to
> > say this - got an email?
>
> > On Dec 27, 9:04 am, Eric Swanson <e_swan...@skybest.com> wrote:
> > > Notice that the quote from Christy is dated May 14, 2003.
>
> > >http://www.spaceref.com/news/viewpr.html?pid=11540
>
> > > John Christy has been proven wrong repeatedly. That particular quote
> > > came out before I showed that there was a problem with the UAH TLT
> > > over the Antarctic. One of the other groups which now produce a data
> > > set from the MSU (Remote Sensing Systems, RSS) excludes all data over
> > > the Antarctic (that is, poleward of 70S) the reason being the high
> > > elevations there. RSS also excludes data from other locations with
> > > high elevations.
>
> > > Curisty's latest results show a global trend of 0.13 C/decade, but
> > > 0.19C/decade for the Northern Hemisphere and only 0.06C/decade for the
> > > Southern Hemisphere. Could it be Christy's results are wrong for the
> > > SH because of the problems over the Antarctic? Is the South Pole
> > > really cooling as his data shows, -0.06 C/decade? Is there a problem
> > > with the ozone layer down there?
>
> > >http://vortex.nsstc.uah.edu/data/msu/t2lt/uahncdc.lt
>
> > > Oh, BTW, Christy fudges the data over the poles, interpolating to fill
> > > in the missing data poleward of 82 degrees. Really now, isn't the
> > > same complaint as has been directed at the CRU, only we know for a
> > > fact he's doing it?
>
> > > I'll believe you are serious when you write Inhoffe and alert him to
> > > the problem...
>
> > > E. S.
> > > --------------------------------------------------------
> > > On Dec 25, 6:14 pm, Robbo <rob...@robertellison.com.au> wrote:
>
> > > > Some major uncertainties in climate science
> > > [cut]
>
> > > > There is a satellite based temperature record of the lower
> > > > atmosphere. This has global coverage and a trend that is less than
> > > > the surface station methodologies.
>
> > > > "Using NOAA satellite readings of temperatures in the lower
> > > > atmosphere, scientists at The University of Alabama in Huntsville
> > > > (UAH) produceda dataset that shows global atmospheric warming at the
> > > > rate of about 0.07 degrees C(about 0.13 degrees Fahrenheit) per
> > > > decade since November 1978," said Dr.John Christy, who compiled the
> > > > comparison data. "That works out to a global warming trend of about
> > > > 0.7 degrees centigrade over 100 years. That's a definite warming
> > > > trend, which is probably due in part to human influences. But it's
> > > > substantially less than the warming forecast by most climate models,
> > > > and it isn't entirely out of the range of climate change we might
> > > > expect from natural causes."
>
> > > > The rate of recent warming is of critical importance in evaluating the
> > > > social and environmental risk of global warming - and it is probably
> > > > the easiest aspect of climate science to spin in the required
> > > > direction.
>
> > --
> > You received this message because you are subscribed to the Google Groups Global Change ("globalchange") newsgroup. Global Change is a public, moderated venue for discussion of science, technology, economics and policy dimensions of global environmental change.
>
> > Posts will be admitted to the list if and only if any moderator finds the submission to be constructive and/or interesting, on topic, and not gratuitously rude.
>
> > To post to this group, send email to global...@googlegroups.com
>
> > To unsubscribe from this group, send email to globalchange...@googlegroups.com
>
> > For more options, visit this group athttp://groups.google.com/group/globalchange- Hide quoted text -
Michael Tobis
planet is simply not possible, even physically.
Perpetually growing GDP is another matter, since money is something of
a fiction. But if you actually anticipate that the rest of the world
will eventually catch up to where the west will be after another fifty
years of growth, you get something like fifty times the current
environmental impact. Or if you want to break even on total
environmental impact, you have to reduce the impact per dollar by a
factor of fifty. That's just to keep the rate of damage to the
environment fixed.
http://initforthegold.blogspot.com/2009/05/cruel-hoax-growth-and-equity-cannot-be.html
mt
James Annan
> Climate
> could be either warmer of cooler in 100 years and there is absolutely
> no way of meaningfully predicting what it will be.
So you say, but basically every informed scientist in the world
disagrees with you.
James
Robbo
- primarily food, energy or other physical resources. It is health,
education, government, MTV etc. It is a matter of engineering
sustainable systems - by definiton having negligible environmental
impact.
Population will peak at about 9 billion (UN source - previously linked
to) in the middle of this century. Reducing that number is a matter
of maximising economic development. You can't have it both ways.
On Jan 2, 12:50 pm, Michael Tobis <mto...@gmail.com> wrote:
> Perpetually growing energy (at a finite growth rate) on a finite
> planet is simply not possible, even physically.
>
> Perpetually growing GDP is another matter, since money is something of
> a fiction. But if you actually anticipate that the rest of the world
> will eventually catch up to where the west will be after another
> years of growth, you get something like fifty times the current
> environmental impact. Or if you want to break even on total
> environmental impact, you have to reduce the impact per dollar by a
> factor of fifty. That's just to keep the rate of damage to the
> environment fixed.
>
> http://initforthegold.blogspot.com/2009/05/cruel-hoax-growth-and-equi...
>
> mt
Robbo
referenced was saying that climate is a dynamically complex system.
Theoretically determinant but practically incalcaluable.
Robbo
mechanism. Weather is a fast response over days and weeks. ENSO
evolves over years, ocean states evolve over decades and there are
millenial long ocean/atmosphere heat transfer processes.
It may be possible to predict tipping points - through the slowing
down method (oscillations that are damped and slow down over time) or
some other approach. As you say, CO2 is one of the things that can
create small changes in initial conditions pushing climate past a
critical point. There are multiple other factors. The outcome of that
- as you say - is not predictable.
We are just realising that we have been thinking the wrong way about
climate - so a cautious and careful modesty in claims is appropriate.
Complex systems theory as applied to climate is a problem with many
degrees of freedom.