Climate Congress, Copenhagen, 10-12 March, 2009
Open letter to Dr Rajendra K. Pachauri, IPCC chair
Dear Dr Pachauri,
The Climate Congress presents an important opportunity to present all
facets of the current situation, explore the ramifications, and
suggest appropriate actions. The aim must be, as far as possible, to
address the threat of a disastrous multi-metre rise in sea level and
catastrophic multi-degree rise in temperature – whenever they might
occur.
We would like to suggest a rather simple division of the problem/
solution domain:
Part A: Emissions reduction
About: Reducing emissions of greenhouse gases into the atmosphere.
Target: Achieve near-zero carbon economies throughout the world by end
century.
Difficulties: International agreement, life-style changes, high cost.
Rationale: Long-term sustainability.
Part B: Carbon stock management
About: Removing CO2 from the atmosphere by various means.
Target: Reduce levels below 350 ppm over next three decades.
Difficulties: May involve change in agricultural practice, worldwide.
Side-effects may be difficult to anticipate.
Rationale: Reduce CO2 climate forcing below its current level, halt
ocean acidification and protect carbon sinks.
Part C: Heat transfer and radiation management
About: Mainly about albedo engineering and solar radiation management.
Priority target: Cool the Arctic sufficient to halt retreat of Arctic
sea ice within three years.
Difficulties: Seen as tampering with the environment, and therefore
intrinsically dangerous; but cost is low and side-effects should be
manageable.
Rationale: Reduce risk of massive methane discharge and stabilise the
Greenland ice sheet.
International focus has been almost entirely on Part A until recently,
when it has been realised that: (1) it is proving extremely difficult
to achieve reductions; (2) the current trend is towards IPCC’s worst
case scenario; (3) lifetime of CO2 had been under-estimated – even if
anthropogenic greenhouse gases could be stopped overnight, the
existing gas levels will live on in the atmosphere for centuries,
causing the global temperature to continue to rise many degrees; (4)
global warming of more than 2 degrees could be disastrous; (5) tipping
points could be reached much sooner than expected.
It is generally recognised that the underlying primary cause of global
warming is the excess of CO2 in the atmosphere. If emissions reduction
can’t reduce it quickly enough, then we have to resort to some form of
geoengineering – or more specifically carbon stock management – see
Part B. Furthermore, ocean acidification is becoming dangerous, and
this can only be tackled by removing CO2 from the atmosphere. So,
within a decade or two, carbon stock management could become
essential, and we should be doing large-scale experimentation now.
But the actions of Part A and Part B cannot prevent tipping points
driven by positive feedback on temperature. Emissions reduction and
carbon stock management cannot produce a cooling effect – certainly
not on the time-scales we are talking about. We have to resort to
other kinds of geoengineering, hence Part C.
As regards tipping points, our perception of the situation has changed
fundamentally since the dramatic retreat of Arctic sea ice in
September 2007. The IPCC had chosen to ignore potential tipping
points, as being too difficult to model or lacking reliable data. But
now some experts are talking about possible summer disappearance of
sea ice within a decade [1], and this possibility is even mentioned in
the introduction to Session 1 of the Congress [2]:
“Sea ice is changing and the sea ice in the northern polar ocean has
retreated in the last few years and might totally disintegrate during
the next decade.”
Sea ice disappearance will accelerate Arctic warming which could
trigger the release of vast amounts of methane from permafrost
(leading to many degrees of global warming) and/or destabilise the
Greenland ice sheet (leading to many metres of sea level rise).
There now appears no other possibility to save the Arctic sea ice than
to cool the Arctic region, by reflecting more sunlight back into
space. There are two prime candidates for this: stratospheric sulphate
aerosols and marine cloud brightening [3]. The former involves the
injection of a H2S or SO2 high in the stratosphere, where it reacts to
form microscopic droplets of sulphuric acid which scatter sunlight
efficiently. This mimics the effect of a volcano like Pinatubo, which
cooled the planet for two years from its sulphur emissions into the
stratosphere. The latter – the brightening of marine clouds – involves
producing a very fine spray of sea water from ships which sail
underneath low-lying cumulus clouds, such that some of the spray wafts
upwards, brightening the clouds and reflecting light back into space.
Modeling suggests that each of these cooling technologies should be
effective, affordable, fast acting, easily reversible and reasonably
safe.
If we can save the Arctic sea ice, then we may be able to avoid other
tipping points such as the methane release from permafrost. Such
action buys time while we reduce CO2 levels and avoid other
catastrophes such as from ocean acidification. On the other hand, if
we do not act with the necessary urgency, we may soon find ourselves
beyond the point of no return: doomed both to many metres of sea level
rise and to spiraling temperatures, way above 6 degrees this century –
temperatures for which the very survival of our civilization would be
in question.
John Nissen
Email:
j...@cloudworld.co.uk for correspondence
Stephen Salter
Professor of Engineering, University of Edinburgh
Peter Read
Hon. Research Fellow, Massey University Centre for Energy Research
Andrew Lockley, London UK
Former director of Friends of the Earth ENWI
John Gorman MA (Cantab), London, UK
Sam Carana, contributor to
feebate.net
sam.c...@gmail.com
References:
[1] Climate Safety report, which can be downloaded from:
http://climatesafety.org/
[2] Climate Congress, Session 1, in:
http://climatecongress.ku.dk/programme/sessions06.03.2009.pdf
[3] Solar Radiation Management:
http://en.wikipedia.org/wiki/Solar_radiation_management