Warning over aerosol climate fix - BBC News
Andrew Lockley
http://www.bbc.co.uk/news/science-environment-32334528
By Simon Redfern
Science writer
16 April 2015
From the section Science & Environment
Any attempts to engineer the climate are likely to result in "different" climate change, rather than its elimination, new results suggest.
Prof Ken Caldeira, of Stanford University, presented research at a major conference on the climate risks and impacts of geoengineering.
These techniques have been hailed by some as a quick fix for climate change.
But the impacts of geoengineering on oceans, the water cycle and land environments are hotly debated.
They have been discussed at a meeting this week of 12,000 scientists in Vienna.
Researchers are familiar with the global cooling effects of volcanic eruptions, seen both historically and even back into the deep past of the rock record.
With this in mind, some here at the European Geosciences Union General Assembly have been discussing the possible worldwide consequences of pumping sulphate aerosols into the stratosphere to attempt to reflect sunlight back into space and cool the planet.
Planetary sunshade
Two hundred years ago this month, the huge volcano Mount Tambora erupted in Indonesia, throwing tonnes of gas and ash into the stratosphere.
Maybe as much as 100 million tonnes of sulphur dioxide aerosols spread as a blanket around the globe, acting like a planetary sunshade.
Global temperatures plummeted, and across America and Europe 1816 became known as the year without a summer.
Such global cooling processes, but managed in a geoengineering solution, have been touted by some as a possible mechanism to extricate the planet from its path towards a warmer future.
Solar radiation management would use stratospheric sulphate aerosols to dim the Sun. Using a variety of climate models, Ken Caldeira, from the Carnegie Institution for Science in Stanford, California, has investigated the likely consequences of such geoengineering on agriculture across the globe.
Mount Pinatubo
Mount Pinatubo pumped 20 million tonnes of sulphur dioxide high into the sky above the Philippines
His research shows that while dimming could rapidly decrease global temperatures, high CO2 levels would be expected to persist, and it is the balance between temperature, CO2, and sunlight that affects plant growth and agriculture.
Exploring the regional effects, he finds that a stratospherically dimmed world would show increased plant productivity in the tropics, but lessened plant growth across the northerly latitudes of America, Europe and Asia.
It is easy to see how there might be geopolitical shifts associated with changes in regional food production across the globe.
"It's probably the poor tropics that stand to benefit and the rich north that stands to lose," said Prof Caldeira.
But what if geoengineered sulphate aerosols were, nonetheless, deployed and then a large volcanic eruption like Pinatubo in the Philippines took place? Three such eruptions occurred in the last century so the scenario seems likely.
Bad timing
Hannele Korhonen, of the Finnish Meteorological Institute, suggests that the climate impacts could be quite unexpected.
Her results indicate increased temperatures in the Southern Ocean and in northerly latitudes, as well as the mid-Pacific, but cooling in African and Asian mid-latitudes.
Regional weather patterns would still change, as they did after Tambora in 1816, with similar widely felt disruption.
"Deploying solar radiation management methods would lead to a completely new climate state with enhanced greenhouse effect and reduced solar radiation," said Korhonen, adding: "There are great uncertainties, related especially to the regional climate impacts of solar radiation management."
Commenting on the results, Helene Muri, of the University of Oslo, said: "These modelling experiments have highlighted the new risks associated with solar radiation management. The safest option is, of course, to reduce greenhouse gas emissions and aim for a more sustainable way of living and managing the planet."
It is not at all obvious what the other consequences of global geoengineering approaches might be. For example, Patrick Applegate from Pennsylvania State University, reported that solar radiation management may yet fail to prevent sea-level rise from melting ice sheets, which respond on much longer time scales than the temperature effects of solar shielding.
Aside from being ineffective in stemming sea-level rise, solar radiation management - according to results from Jerry Tjiputra at Bergen University - would lead to increased ocean acidification in the North Atlantic.
These results also suggest that climate engineering could not offer a long-term solution, with the world eventually being in the same place, by 2200, as it would reach without any geoengineering interventions.
Asked whether he believed solar radiation management would be deployed, Prof Caldeira responded: "A lot has to do with how bad climate change will end up being. Humans are quite adaptable as a species.
"On the other hand, projections for summers in the tropics suggest almost every summer will be hotter than the hottest summer yet on record, associated with crop failures. There is the possibility that there would be widespread crop failures in the tropics in the summer.
"The only thing a politician can do to start the planet cooling is solar geoengineering. If a catastrophic outcome does occur, the pressure to deploy a scheme could be overwhelming.
"Research into this is an act of desperation on the part of scientists. People see the greenhouse gas concentrations increase and are looking for other ways to reduce environmental risk."
Ronal W. Larson
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Schuiling, R.D. (Olaf)
I would like to express it better, what politicians should do:
“the best thing that politicians can do is to intensify the process that has throughout the geological history of the Earth captured its CO2 and stored it safely in rocks” Olaf Schuiling
Motoko
to 1.
I attended only a few of the biochar presentations. From the program and the presentation I it seemed that biochar has not been studied as a CE measure. Most of the talk/posters were about soil enhancement. (BTW, it is the international year of soil.) Some authors of CE-biochar papers have been present but were not talking about CDR.
There has also been a press conference with the some of the people that have been at the CE session.
http://meetingorganizer.copernicus.org/EGU2015/session/19804
to 2.
Conveners of the session have been Helene Muri, Simon Driscoll, and Peter Irvine.
The session seemed balanced. Some talked about the interlink of a volcanic eruption and stratospheric SRM (Korhonen) or sea-level rise and SRM (Applegate). I wouldn't call them in particular positive rather then very negative.
Nils
Ronal W. Larson
Dear Ron,
to 1.
I attended only a few of the biochar presentations. From the program and the presentation I it seemed that biochar has not been studied as a CE measure. Most of the talk/posters were about soil enhancement. (BTW, it is the international year of soil.) Some authors of CE-biochar papers have been present but were not talking about CDR.
There has also been a press conference with the some of the people that have been at the CE session.
http://meetingorganizer.copernicus.org/EGU2015/session/19804
to 2.
Conveners of the session have been Helene Muri, Simon Driscoll, and Peter Irvine.
The session seemed balanced. Some talked about the interlink of a volcanic eruption and stratospheric SRM (Korhonen) or sea-level rise and SRM (Applegate). I wouldn't call them in particular positive rather then very negative.
Nils
Am 20.04.2015 um 05:01 schrieb Ronal W. Larson:
Andrew and list
1. Besides your message below being about Prof. Caldeira’s comments on SRM, this is a nice reminder that a major “Geo”-related conference ended a few days ago. At:I found about 40 oral and poster presentations on biochar and about the same number with a biomass flavor. This seems to be down a little from the previous year, found at:Could those who attended give us a flavor for how the various SRM and CDR/NET approaches were being viewed by conference attendees?
2. I was surprised to see Prof. Caldeira’s session had only 4 other papers on SRM - none of which seemed particularly positive.
3. With apologies for bringing up the “only” subject again so soon, I wonder if others see a disparity with the above statistics and a sentence almost at the end below:"The only thing a politician can do to start the planet cooling is solar geoengineering.Ron
On Apr 17, 2015, at 3:16 PM, Andrew Lockley <andrew....@gmail.com> wrote:
http://www.bbc.co.uk/news/science-environment-32334528
By Simon Redfern
Science writer
<snip>
<SNIP>“The only thing a politician can do to start the planet cooling is solar geoengineering. If a catastrophic outcome does occur, the pressure to deploy a scheme could be overwhelming.
Ronal W. Larson
Parminder Singh
Parminder Singh
Michael Hayes
John Nissen
--
Andrew Lockley
In theory, I would have thought a rapid drop in CO2 emissions should cause global temperatures to drop pretty quickly, as ocean uptake will remove a lot of historical emissions. You'd have to keep sulphur emissions constant for this to happen, though.
Choosing whether to maintain sulphur protection is one of the ways to 'get the camel's nose in the tent', as far as SRM acceptability goes.
A
Doug MacMartin
Plot is from Cao et al, 2011. Zeroing emissions does cause CO2 to drop somewhat, but the climate is not yet in equilibrium with current CO2 levels, so the net effect is roughly constant temperature, all else being equal.
Michael Hayes
In conclusion; To quote Dr. Sallie Chisholm on her views concerning geoengineering as it is most popularly defined (SAI?); "Proponents of research on geoengineering simply keep ignoring the fact that the biosphere is a player in what ever we do, and its trajectory cannot be predicted. It is a living breathing collection of organisms that are evolving every second-a 'self-organizing, complex, adaptive system'. These types of systems have emergent properties that simply cannot be predicted. We all know this! Yet proponents of geoengineering research leave that out of the discussion.".
Bio-geoengineering, through marine biomass production/biochar/olivine/bio-energy/MCB etc., does not neglect the above obvious reality, as so well put forth by Dr. Chisholm, as the bio-geoengineering suite of technologies are all flexible enough to keep pace with a self-organizing, adaptive and vastly complex planetary system(s).....while also achieving RCP 2.6.
Whereas, SAI does profoundly neglect the emergent/evolutionary properties of nature and does so at a fundamentally critical level....sunlight!!! And, SAI does nothing towards assistance in our critical need to achieve the RCP 2.6 scenario.
Thus, SAI, under its current deployment protocol, must be viewed at the policy, socioeconomic and environmental levels as being highly un-necessarily un-safe and the claim that SAI is "The only thing a politician can do to start the planet cooling is solar geoengineering' is simply not supportable at the STEM/policy levels....on the face of it..