Testing brightwater

[Andrew Lockley]

Hi

It seems to me that Brightwater is suitable for 'homebrew' testing, and indeed would greatly benefit from this work.  Water bodies are very variable by salinity, choppiness, cloudiness, temperature, etc.

Is it possible to create a set of standard tests which can be conducted by people to test BW in their local area? A bucket filled with seawater in California may behave very differently to a bucket of seawater in Scotland.

I would imagine that it would be possible to test the idea using a 2 gallon bucket, a bicycle or car tyre pump, clock, standard diffuser nozzle and a ruler with a coin taped to it (for checking cloudiness).  A colour- comparison chart may also be useful.  Sure, these would be very basic results, but they would be very helpful if (for example) we discovered that water near river mouths was better than water from open ocean shorelines.  I'm guessing that all the equipment that wasn't available in an average home would be able to be bought and posted for likely a lot less than 50 dollars.  

I may be offending the sensibilities of those with big labs and high standards, but my guess is we could quickly gain some very useful data on this with the participation of some people on this list, and maybe beyond.  Who knows, maybe this could become a very popular experiment in schools and colleges?

A

[Michael Hayes]

Andrew, "Bright Water" is not a new concept. It was proposed as a means to reduce hull drag some time ago. Funding is the issue!!!! 

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[Andrew Lockley]

Michael,

I'm not saying the production of microbubbles is a new idea.  However, I'm not aware of any programme of testing of the behaviour of such bubbles in real waters from around the world.  The key issue is residence time, and we simply don't know how that will be affected by the myriad types of waters which the technology could be deployed in. Whilst testing in canals and reservoirs under the pretext of reducing evaporation makes a lot of sense, any deployment at scale will be in the sea, and so testing seawater is logically a better test.

My suggestion is that by concocting a simple series of 'homebrew' experiments we can gather some really useful data which can help the modelling of this technology tremendously.

I for one would not know whether the silty waters of the Thames estuary would make better microbubble waters than the bright green biologically active water of Portsmouth harbour.  Do you have any data which could answer this question, without recourse to an experiement?

An experiment should settle the matter.  Furthermore, an experiment would raise public awareness of, and interest in geoengineering.  It's not practical for school children to launch balloons into the stratosphere, but they could be very helpful in blowing bubbles into buckets of seawater with a bicycle pump.  It may not be sexy, but my guess is it will be a good test to gather some crude raw data for later modelling.

A

[Nathan Currier]

The recent bright water discussions are interesting to me partly as a
psychological phenomenon. Just as Seitz begins his paper noting the
similarity between hydrosols in water and aerosols in air, with
hydrosols having their attendant analogues to the “Twomey effect” –
similarly complex issues of their size and their effects on light
scattering, etc. – so the bright water story starts to seem like a
kind of oceanic parallel of the whole stratospheric sulfur story.

In their joint piece last year reviewing various geoengineering
options (in Issues in Science and Technology, 2010), white surfacing
was listed by Keith/Caldeira at the very bottom in order of
“likelihood of feasibility at large scale” for all SRM approaches,
even below satellites in space. Obviously, it was a minor error in
their fine review and was partly just grammatical – spreading white
paint is surely more ‘feasible’ than putting reflector shields into
outer space – but I think it was also partly a reflection of a common
reflex: there is a natural desire to find a geoengineering technique
that can have the greatest maximum potential impact and gives the
greatest bang for the buck, as quickly as possible. Just as aerosol
SRM quickly became a cynosure, bright water now is starting to have a
similar kind of fascination and buzz – it could have significant
maximum potential, sounds initially like it might not be too costly,
and it involves physical issues that are notoriously complex, meaning
that one can easily keep one’s eye on the extremely simple and highly
desired goal – its potential for lots of cheap, quick cooling – but be
unable to draw any precise picture of its negatives and thus to
compare it accurately to much more modest proposals.

Keith/Caldeira surely meant to say that white surfacing is more
limited in its maximum potential impacts than the other SRM techniques
they discussed, which is true. But it is clearly much more ‘feasible,’
really at the top of feasibility, of all SRM today, in the sense that
there are few objections from anyone to doing it right now, it
wouldn’t be very costly, could even save people money and give some
modest help to the climate through its SRM and its co-benefit of
reduced GHG emissions (biochar is in a somewhat analogous position,
and wasn’t mentioned). With a Pacala/Socolow-type approach to
stabilization of emissions applied to geoengineering techniques, white
surfacing could become an important technique within the mix, one we
can start with right away, unlike almost all others, and it might be
that the impact it can offer safely might not be that small compared
to that of aerosols in the end (and its comparative economics might
look pretty good, too, if aerosol ‘collateral damage’ remains a
problem).

Now then, let’s jump into the ocean – there’s bright water in place of
aerosols, and there could be floats just like white surfacing. Just as
aerosol SRM seems more dicey the closer one looks at it, there might
be all kinds of analogous issues involving the mixing of surface
waters and their oxygenation, and surely problems involving biotic
impacts are likely to be much more thorny with hydrosols than with
aerosols. Meanwhile, simple floats are something like the oceanic
equivalent of white roofing, and they seem among the least explored
here in these discussions. They are low-tech and they aren’t very
sexy, but perhaps floats could be designed to be strung together as
‘artifical ice floes’ to be used in previously iced-over areas or
somewhat south of the Bering strait, perhaps taking advantage of
differing currents to stay held in gyre-like motions, their surfaces
above the water except for their ‘legs,’ allowing heat release, and
with hanging “side-teeth” to create windbreak, and the tops having a
very high albedo, made from recycled plastics. Compared to white
roofing, they would have the advantage that once developed they could
be placed in areas of great immediate strategic value for the climate,
like the ESAS, or south of it.

I guess I’m a bit skeptical about the ‘1,000 windmills’ energy cost in
the Seitz paper, and perhaps I’m just being completely ignorant, but
if I simply try to imagine to myself a given 12’x12’ patch of ocean
and trying to keep its albedo raised for the next 20 years by
continuously making bubbles there, and then I picture making a float
with a very high albedo top out of recycled plastics and letting it
just sit there for a couple of decades, it would seem the latter would
be energetically much better. With tens of millions of tons of various
plastic waste every year, much of it easily reformed into the EPS,
etc, out of which docks are often made today, could it really be
energetically better to make bubbles that don’t last, that demand
constant energy input, involve complex machinery that would have to
withstand tough oceanic conditions, and that would have much more
complex interactions with oceanic life?

But I’m all for doing everything we can, so I truly do hope that
bright water gets investigated as fully as possible – and I hope that
it works, too – but I also hope that it is not concentrated on here to
the exclusion of the more humble and low-tech things, which sometime
seem relatively unexplored in these discussions.

[Josh Horton]

There is an additional, very significant difference between bright
water (as well as marine cloud brightening) on the one hand, and
sulfate aerosols on the other: microbubbles and seawater sprays would
be much more socially acceptable to most people than sulfate aerosol
injections. I'm willing to bet that the average person in any part of
the world would find "air bubbles" and "whiter clouds" a lot more
benign than "sulfur dioxide," regardless of the fact that any sulfur
injected would amount to a fraction of current emissions, would mimic
natural eruptions, etc. We shouldn't underestimate these
sociocultural dimensions, which will influence decisions on testing
and deployment.

Josh Horton
joshuah...@gmail.com
http://geoengineeringpolitics.blogspot.com/

[Ken Caldeira]

It is clearly easy to spread some white paint around. It is difficult to do at large scale. Thus the issue of scalability is at the heart of our rationale for placing surface whitening proposals near the bottom of our list which we said was "in approximately decreasing likelihood of feasibility at large scale".

http://dge.stanford.edu/labs/caldeiralab/Caldeira%20downloads/Caldeira_Keith_IS&T2010.pdf

Estimates of "likelihood of feasibility" with limited information are unlikely to lead to robust ordering of options.

---

Microbubbles would be worth observing in real systems to see how they behave. While I remain skeptical, I do think this worth investigating.

In informal conversations with people who study bubbles in the ocean, issues that have been raised include how to keep such tiny bubbles near the surface, give their propensity to be mixed downward with wind-driven mixing and to attach themselves to sinking particles (see attachment for some relevant discussion).

___________________________________________________
Ken Caldeira

Carnegie Institution Dept of Global Ecology
260 Panama Street, Stanford, CA 94305 USA
+1 650 704 7212 kcal...@carnegie.stanford.edu
http://dge.stanford.edu/labs/caldeiralab  @kencaldeira

[Nathan Currier]

Hey, Ken -

I guess it's a matter of seeing the glass half full...If I remember
correctly the material of out LBL
(Akhbari & Rosenfeld 2007, 2010, etc) actually cited help from you on
their RF translations for white surfacing, so you're
clearly as much 'in the know' as anyone on all their figures, and the
question is just whether one finds ~40 Gt CO2e
total global potential very "difficult" to achieve (what it would do
to TiO2 markets, etc) and whether that is "large scale" enough
to really count for much. What I meant with feasibility - or let's use
the word practicality - is really this: as an example, I had been
asked last year by some of Bill McKibben's folks to come up with a
plan for this Earth Day, and while they apparently
never went with it, the plan would have involved doing some part of
that 40 Gt (sorry I'm traveling & don't have it with me - but of
course it would only have been a small fraction of that) with
volunteers, perhaps 100,000 of them & then people/companies in each
community donating money for each volunteers' surfacing (kind of like
sponsors for cancer walks, etc) and had it gone ahead, it would have
been completed LAST WEEK. No United Nations, International Courts, no
legislation, no proclamations against you from a hundred environmental
groups. That's what I mean by practical. If we could come up with 10
little ideas that no one minded and each can get -.05 W/m2, that can
really help save our skin.........I know that wouldn't be easy either,
but, like the tortoise and the hare, you never know what strategy
might win the race, so don't disregard the 'little ideas' that can be
enacted now, that's all I meant.......anyhow, on bright water, I must
confess my reaction was somewhat like Michael Hayes' in his post
today, although I could certainly picture it becoming locally very
helpful around coral reefs, as someone suggested......




On Apr 26, 6:00 pm, Ken Caldeira <kcalde...@carnegie.stanford.edu>
wrote:

> It is clearly easy to spread some white paint around. It is difficult to do
> at large scale. Thus the issue of scalability is at the heart of our
> rationale for placing surface whitening proposals near the bottom of our
> list which we said was "in approximately decreasing likelihood of
> feasibility at large scale".
>

> http://dge.stanford.edu/labs/caldeiralab/Caldeira%20downloads/Caldeir...

>
> Estimates of "likelihood of feasibility" with limited information are
> unlikely to lead to robust ordering of options.
>
> ---
>
> Microbubbles would be worth observing in real systems to see how they
> behave. While I remain skeptical, I do think this worth investigating.
>
> In informal conversations with people who study bubbles in the ocean, issues
> that have been raised include how to keep such tiny bubbles near the
> surface, give their propensity to be mixed downward with wind-driven mixing
> and to attach themselves to sinking particles (see attachment for some
> relevant discussion).
>
> ___________________________________________________
> Ken Caldeira
>
> Carnegie Institution Dept of Global Ecology
> 260 Panama Street, Stanford, CA 94305 USA

> +1 650 704 7212 kcalde...@carnegie.stanford.eduhttp://dge.stanford.edu/labs/caldeiralab @kencaldeira

>
> On Tue, Apr 26, 2011 at 2:08 PM, Josh Horton <joshuahorton...@gmail.com>wrote:
>
>
>
> > There is an additional, very significant difference between bright
> > water (as well as marine cloud brightening) on the one hand, and
> > sulfate aerosols on the other: microbubbles and seawater sprays would
> > be much more socially acceptable to most people than sulfate aerosol
> > injections.  I'm willing to bet that the average person in any part of
> > the world would find "air bubbles" and "whiter clouds" a lot more
> > benign than "sulfur dioxide," regardless of the fact that any sulfur
> > injected would amount to a fraction of current emissions, would mimic
> > natural eruptions, etc.  We shouldn't underestimate these
> > sociocultural dimensions, which will influence decisions on testing
> > and deployment.
>
> > Josh Horton

> > joshuahorton...@gmail.com

>  Mulhearn_JGR1981.pdf
> 598KViewDownload

[Andrew Lockley]

The below is forwarded at Russells suggestion.

My thinking on the matter is that even much larger bubbles will provide a useful analogue for experimentation - hence my suggestion of using a diffuser and hand pump to trial the idea in different waters to check lifetimes.

If anyone can think of good homebrew experiments to test the idea in  different waters, please reply.

A 

---------- Forwarded message ----------
From: "Russell Seitz" <russel...@gmail.com>
Date: 22 Apr 2011 00:23
Subject: Re: Testing brightwater
To: "Andrew Lockley" <andrew....@gmail.com>

I hope you will find the paper and its references helpful in informing your beliefs , but  that presumes some familiarity with  physical properties of water  and the component gases of  air ,including their solubility curves - CO2 is vastly different from  say N2, but you want to create a briefly visible  hydrosol of sorts . just twist the cap of a warm bottle  of club soda. 

It will  flash white  as microbubbles nucleate. 

You then have  a few hundred milliseconds  to twist the cap back on before the bubbles grow several  thousandfold  in diameter, and displace enough water to spray you in the face.

If you can get such a system to settle down instead of erupting ,  at a point before the nucleated bubbles become visibly large and so prone to rise,  and you dilute it to ~ 1ppmv, you will  have a DIY  hydrosol. 

It won't look like much to the naked eye, though, unless it's several meters thick- you can scarcely brighten water unless it's deep enough to be dark in the first place. 

I hope this crude illustration  helps, and if it does , please share it with the group

 
On 21 April 2011 14:09, Andrew Lockley <andrew....@gmail.com> wrote:
>
> Is transparency change a good proxy? It looks so from your tank . You'd need to correct for the existing murkiness using a control which settles at the same rate.
>
> My suggestion is that a bicycle pump with a diffusion nozzle should work.  Failing that you could use a soda fountain cartridge, but that's co2 not air. You can use the cartridge to pump air, but that's a bit complicated.
>
> I don't know what's the best method, but I believe a homebrew experiment mat be possible . I hope you can help me work this up.
>
> A
>
> On 21 Apr 2011 16:26, "Russell Seitz" <russel...@gmail.com> wrote:
> > Water transparency and undershine are two different things
> >
> > On 21 April 2011 11:23, Russell Seitz <russel...@gmail.com> wrote:
> >
> >> With what will you supersaturate the water with air?
> >>
> >>
> >> On 21 April 2011 05:11, Andrew Lockley <andrew....@gmail.com> wrote:
> >>
> >>> It was a serious suggestion Russell. With the right nozzle, I'm sure a
> >>> school yard experiment can yield useful results, using change in opacity
> >>> measured visually.
> >>>
> >>> Take two buckets, bubble one. Leave them in the school yard. Measure
> >>> invisibility depth of a bright coin hourly, then daily, until there's no
> >>> longer a difference.
> >>>
> >>> How is that not a useful test?
> >>>
> >>> A

> >>> On 21 Apr 2011 05:38, "Russell Seitz" <russel...@gmail.com> wrote:
> >>> > " a bicycle or car tyre pump, clock, standard diffuser nozzle and a
> >>> ruler
> >>> > with a coin taped to it (for checking cloudiness)."
> >>> >

> >>> > Don't forgot the coyote .
> >>> >
> >>> > On 20 April 2011 20:28, Andrew Lockley <andrew....@gmail.com>

> >>> > --
> >>> > Russell Seitz
> >>> > Fellow of the Department of Physics
> >>> > Harvard University
> >>> > Cambridge MA 02138
> >>> > 617 661- 0269
> >>> >
> >>> > www.adamant.typepad.com
> >>> >
> >>> > This message and its attachments may contain confidential or proprietary
> >>> > information. and the unauthorized distribution copying or dissemination
> >>> of
> >>> > this message, text,and any attached or displayed content is strictly
> >>> > forbidden. © Russell Seitz 2008 all rights reserved.
> >>>
> >>
> >>
> >>
> >> --
> >> Russell Seitz
> >> Fellow of the Department of Physics
> >> Harvard University
> >> Cambridge MA 02138
> >> 617 661- 0269
> >>
> >> www.adamant.typepad.com
> >>
> >> This message and its attachments may contain confidential or proprietary
> >> information. and the unauthorized distribution copying or dissemination of
> >> this message, text,and any attached or displayed content is strictly
> >> forbidden. © Russell Seitz 2008 all rights reserved.
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >
> >
> > --
> > Russell Seitz
> > Fellow of the Department of Physics
> > Harvard University
> > Cambridge MA 02138
> > 617 661- 0269
> >
> > www.adamant.typepad.com
> >
> > This message and its attachments may contain confidential or proprietary
> > information. and the unauthorized distribution copying or dissemination of
> > this message, text,and any attached or displayed content is strictly
> > forbidden. © Russell Seitz 2008 all rights reserved.

--
               Russell Seitz
 Fellow of the Department of Physics
            Harvard University
         Cambridge MA 02138
              617  661- 0269

www.adamant.typepad.com

This message and its attachments may contain confidential or proprietary information. and the unauthorized distribution copying or dissemination of this message, text,and any  attached or displayed content is strictly forbidden. ©  Russell Seitz 2008 all rights reserved.

[Michael Hayes]

Hi All,

The "Home Brew" experiment setup seems like a good idea for education/experimentation. I would like to offer a few layperson suggestions. 

For the diffuser, what about using a water filtration element that filters water down to the micron level? This may produce micron sized air bubbles if you pump air, as opposed to, water through it. Here is a 0.5 micron filter cartridge costing $25 http://www.google.com/products/catalog?q=micron+water+filter+cartridges&hl=en&cid=4793115905088379626#p

Attaching the bare cartridge to a air hose is something the local hardware store would help with. You can buy threaded metal tubing and use that as a rod to bolt plates to the top and bottom and simply drill a few holes into the threaded pipe section which is within the filter area. An end cap would be needed. The air hose can be fitted to the pipe with a nipple screw on adapter. The normal water pressure limit for this type of cartridge is 45 PSI which seems reasonable for hydrosol production.

I would like to propose the use of a biodegradable surfactant in a controlled variant of the experiment. Soy oil is used in some medical related microbubble production techniques. A few drops being delivered into the air stream should prove interesting. This also brings up the potential contamination of air compressor oil. Most larger air compressors will put out a trace amount of oil in the air and that would be an uncontrolled surfactant. Controlling for that would seem important. The use of a hand pump would go around this, but, would you get the needed continuous pressure? Fluctuations in air pressure may produce different bubble sizes(?). This type of diffuser could be linked together to provide a long line of hydrosol dispersion.  

There are low cost light meters used in photography which would help provide a reliable light (opacity) reading for the experiment. A large fish aquarium would allow for the use of such a meter. Having a meter on one side and a light bulb on the other side of the tank seems like a good set up. This is more of a hunch than advice. 

Also, working with a local marine aquarium for the temporary use of their larger display tanks may be another educational/experimental option. The marine biology community will obviously be taking a high level of interest in hydrosol deployment. Gaining their cooperation at this stage would be important and possibly helpful in choosing an expectable list of surfactants.

In a slightly off topic subject; If hydrosol deployment can be coupled to the issue of ocean acidification, the combination of the 2 may find broader support. Finding a way to deliver an PH treatment while deploying the hydrosol would seem technologically simple. Injecting small measured amounts of Ammonia (?) gas into the hydrosol air injection system could adjust PH levels in the surrounding waters. This, obviously, has many questions concerning marine life health and hydrosol stability. I only offer it as a possible variant to the proposed table top experimentation. The production of hydrosol would use the exact type of operation needed to introduce a gaseous PH treatment for wide ocean areas.

The issue of bubble adhesion (growth) may possibly be addressed through manipulation of the surfactant's lamination ion load along with that of the internal air. One would be ionic, the other anionic. This.... may.... set up a tenergistic bubble structure. Here are 2 clips giving a visual of what I have in mind.

http://www.youtube.com/watch?v=hOoCHQIyF0s&feature=related

http://www.youtube.com/watch?v=-6I3utbJ1M8

Thus, ion manipulation of the two bubble components may produce a more resilient bubble by strengthening the surfactant lamination cohesion (compression) through static electrical adhesion to the internal air. This is pure speculation and may violate numerous known laws of biology/chemistry and general physics...  

Sonification of the surfactant in the presence of a high voltage current may be a possible experimental path. As surfactants are typically long chained, sonification in a high electrically stressed environment may produce an interesting experiment (or simply a beaker full of gooo). Sonification is used, however, in medical micro bubble preparations as a fluid/surfactant mixing means. The introduction of electrical stress into the process is something that I can not find background information on at this time. If ion manipulation proves out to be practical at the table top level, rigging up an experimental high throughput diffuser should be relatively straight forward.

Multiple surfactant laminations are possible, but, that leads into greater complications of production, cost and possible second order chemical/biological effects within the real world.

These suggestions do go well beyond the simplicity and lower cost of the bucket/penny experiment. I have no expertise in any of the chemical issues and thus may be completely off! But, I hope that they do offer some useful input. 

- Show quoted text -

Reply

Forward

[Andrew Lockley]

Russell,

I've been thinking further about testing the 'brightwater' idea.
Reference Seitz, R. (2010). "Bright water: Hydrosols, water
conservation and climate change". Climatic Change 105 (3–4): 365–381.
doi:10.1007/s10584-010-9965-8

I'm interested to know whether the salinity of the water is likely to
have a material effect?

My suggestion is that testing in rivers would be a good first step.
There is limited mixing with unaltered water, and there should be a
clear correlation between distance and time, which would potentially
allow residency testing in a variety of different temperatures and
turbidity environments with ease. Costs of such testing could be
considerably lower than in open water, as an unmanned bubbler could be
placed in a static location, left running, and samples taken
downstream. By using a pseudorandom pulse, it should be possible to
get a very clear indication of the effect of mixing and dilution on
the bubble flow. Albedo and turbidity measurements could be taken
continuously.

However, all of that is irrelevant if it doesn't work in rivers.
Perhaps you, or another reader, could comment.

Thanks

A

[John Nissen]

Hi all,

I would be very keen to explore methods of cooling rivers, with a view to urgent deployment on rivers flowing into the Arctic.  The size and lifetime of bubbles is crucial for maintaining reflective properties.  But lifetime is most puzzling from the physics [1].  Thus experimentation is vital.  And one needs to consider that these rivers may contain outflow water from wetlands and thermokast lakes which have a high concentration of dissolved methane.  We also need to consider the combination of biological methods of reducing such methane with the bubble brightening technology.

The cooling of rivers flowing into the Arctic is important because of escalating methane emissions from shallow seas in the Arctic [2].  But help in cooling the Arctic generally could prove vital because Arctic amplification is now thought to be a major driver of climate extremes [3], precipitating a growing food crisis as reported in the Huffington Post [4].  The collapse of sea ice can now be expected before 2015 as the sea ice volume continues its decline (closely following the exponential trend curve for each month) [5], further exacerbating the situation [6].

Cheers,

John

[1] http://www.jsst.jp/e/JSST2012/extended_abstract/pdf/104.pdf

[2] Shakhova, personal communication

[3] http://www.youtube.com/watch?v=4spEuh8vswE

[4] http://www.huffingtonpost.com/dr-reese-halter/missing-sea-ice-ameg-and-_b_1753994.html

[5] http://climateforce.files.wordpress.com/2011/07/piomas.png

[6] http://thinkprogress.org/climate/2012/08/04/634901/arctic-death-spiral-continues-new-record-low-sea-ice-volume-appears-likely/

--

[Nathan Currier]

Hi, John -

Yes, I agree, but I think that it might be easier through ice itself.

The Lena seems by far the most important for what you mention, as it flows to about the fastest warming
part of the arctic, carries lots of water to the primary methane hotspots of ESAS, its waters arrive there
already methane-saturated, etc. Its annual outflow is enough to add a meter to the whole Laptev, and its
waters directly get to the seabed right around the region of the ESAS with the maximum number of taliks,
frequent seeps, etc. So this could possibly help things.

Much of the Lena freezes in winter. People drive their cars over it. A big issue
is that the south melts well before the north, the mouth. This causes annual flooding
near the mouth, around very rich wetlands. Explosive charges tend to get used to free
up the flooding, which tends to move around from year to year.

Instead, one thing I've thought of is that perhaps ice-thickening ideas, which have elsewhere been
discussed at this group, could be used far up river, helping to coordinate the timing of the river's melt 

season along its course, which would then disperse the build-ups at the more sensitive areas down river,
decrease the methane saturation (which surely must get enhanced in the big mid-spring flooding
episodes), and generally keep the waters somewhat cooler all around.

Cheers, 

Nathan 

[Russell Seitz]

re "testing in canals and reservoirs"  

It's not a pretext , Andrew- it's a primary goal, hence the title of the paper in question :

 'Bright water: hydrosols, water conservation and climate change.'

[RAU greg]

Arctic cap on course for record melt: US scientists

By Shaun Tandon (AFP) –

WASHINGTON — The Arctic ice cap is melting at a startlingly rapid rate and may shrink to its smallest-ever level within weeks as the planet's temperatures rise, US scientists said Tuesday.

Researchers at the University of Colorado at Boulder said that the summer ice in the Arctic was already nearing its lowest level recorded, even though the summer melt season is not yet over.

"The numbers are coming in and we are looking at them with a sense of amazement," said Mark Serreze, director of the National Snow and Ice Data Center at the university.

"If the melt were to just suddenly stop today, we would be at the third lowest in the satellite record. We've still got another two weeks of melt to go, so I think we're very likely to set a new record," he told AFP.

The previous record was set in 2007 when the ice cap shrunk to 4.25 million square kilometers (1.64 million square miles), stunning scientists who had not forecast such a drastic melt so soon.

The Colorado-based center said that one potential factor could be an Arctic cyclone earlier this month. However, Serreze played down the effects of the cyclone and said that this year's melt was all the more remarkable because of the lack of special weather factors seen in 2007.

Serreze said that the extensive melt was in line with the effects of global warming, with the ice being hit by a double whammy of rising temperatures in the atmosphere and warmer oceans.

"The ice now is so thin in the spring just because of the general pattern of warming that large parts of the pack ice just can't survive the summer melt season anymore," he said.

Russia's Roshydromet environmental agency also reported earlier this month that the Arctic melt was reaching record levels. Several studies have predicted that the cap in the summer could melt completely in coming decades.

The thaw in the Arctic is rapidly transforming the geopolitics of the region, with the long forbidding ocean looking more attractive to the shipping and energy industries.

Five nations surround the Arctic Ocean -- Russia, which has about half of the coastline, along with Canada, Denmark, Norway and the United States -- but the route could see a growing number of commercial players.

The first ship from China -- the Xuelong, or Snow Dragon -- recently sailed from the Pacific to the Atlantic via the Arctic Ocean, cutting the distance by more than 40 percent.

Egill Thor Nielsson, an Icelandic scientist who participated in the expedition, said last week in Reykjavik that he expected China to be increasingly interested in the route as it was relatively easy to sail.

But the rapid melt affects local people's lifestyles and scientists warn of serious consequences for the rest of the planet. The Arctic ice cap serves a vital function by reflecting light and hence keeping the earth cool.

Serreze said it was possible that the rapid melt was a factor in severe storms witnessed in recent years in the United States and elsewhere as it changed the nature of the planet's temperature gradients.

The planet has charted a slew of record temperatures in recent years. In the continental United States, July was the hottest ever recorded with temperatures 3.3 degrees Fahrenheit (1.8 Celsius) higher than the average in the 20th century, according to the National Oceanic and Atmospheric Administration.

Most scientists believe that carbon emissions from industry cause global warming. Efforts to control the gases have encountered resistance in a number of countries, with some lawmakers in the United States questioning the science.

Copyright © 2012 AFP. All rights reserved

[Russell Seitz]

Michael, hull drag reduction is not based on microbubbles, but mechanically generated macrobubbles of milimeter dimensions.

Though individually a billion times larger in volume, for a given amount of air they collectively present less than a thousanth of the optical backscattering cross section provided by the micron sized bubbles discussed in the Bright Water paper.