Scientists call for research on geoengineering scheme to block sunlight

Jeremy Hance
mongabay.com
January 27, 2010



The idea goes something like this: nations would send megatons of light-scattering aerosol particles into the globe's upper atmosphere, significantly reducing sunlight reaching the earth and thereby immediately cooling the Earth. While the idea may sound like science-fiction—or desperate, depending on your opinion—researchers writing in Science say that it may be one of the best ways to lower the Earth's temperature. They argue that international research and field testing of the idea, known as solar-radiation management (SRM), should begin immediately.

"Solar-radiation management may be the only human response that can fend off rapid and high-consequence climate change impacts. The risks of not doing research outweigh the risks of doing it," says co-author David Keith, director of the Institute for Sustainable Energy, Environment and Economy's energy and environmental systems group and a professor in the Schulich School of Engineering.

The researchers fear that if international research does not start soon, nations may begin researching and testing the idea unilaterally, thereby increasing the risk that down the road a rogue nation will begin SRM without the consent of others.

In the opinion-piece, the scientists say that an international research budget of 10 million should begin now and grow to 1 billion by 2020.

However, the authors add that SRM technology should not be considered a cure-all: nations would still need to make big cuts in their greenhouse gas emissions to avoid climate disaster.

"We must develop the capability to do SRM in a manner that complements such cuts, while managing the associated environmental and political risks," the authors write, adding that, "the two are not in opposition. We are currently doing neither; action is urgently needed on both."

One clear benefit of SRM is that it would begin cooling of the Earth immediately, whereas large cuts in greenhouse gas emissions will take many decades before the climate responds, since time is required for CO2 already in the atmosphere to break down.

While SRM is seen by many as the 'safest' and cheapest of the geoengineering proposals to date, there are risks, including a decrease in precipitation and evaporation. In addition, the effects of SRM would likely not occur consistently over the whole planet.

"If the world relies solely on SRM to limit (global) warming, these problems will eventually pose risks as large as those from uncontrolled emissions," the researchers write.

The writers say that only further research and small-scale tests would allow scientists to understand the risks and benefits of SRM more fully.

"If SRM proves to be unworkable or poses unacceptable risks, the sooner we know the less moral hazard it poses; if it is effective, we gain a useful additional tool to limit climate damages," they write.







Related articles

Underwater rocks could be used for massive carbon storage on America's East Coast

(01/05/2010) Considering it is unlikely that global carbon emissions will start dropping anytime soon, researchers are beginning to look at other methods to combat climate change. One of these is to hook polluting power plants up to massive carbon sinks where instead of the carbon going into the atmosphere it would be stored away in rocks. The process is known as carbon capture and storage or CCS. But before one can even debate the pros and cons of setting up CCS, scientists must see if high-quality sites exist.


Ocean fertilization will not help reduce CO2 levels, suggests experiment

(03/24/2009) A controversial 'ocean fertilization' experiment suggests seeding the seas with iron to boost carbon-absorbing phytoplantkon will not sequester much carbon dioxide from the atmosphere. Some — including researchers and private companies — had hoped iron fertilization might be an easy fix for climate change.


Biochar and reforestation may offer better global cooling potential than ocean fertilization

(01/28/2009) The first comprehensive assessment of the climate cooling potential of different geoengineering schemes has been conducted by researchers at the University of East Anglia (UEA). The results are published in the journal Atmospheric Chemistry and Physics Discussions


Mirrors in the desert may fight global warming

(12/23/2008) Heat reflecting sheets in arid regions could cool climate by increasing Earth's reflectivity or albedo, argue scientists writing in the International Journal of Global Environmental Issues.


Geoengineering schemes need ranking system to avoid wasting money, destroying the planet

(10/26/2008) Schemes to alter Earth's climate on a planetary scale should be ranked according to their efficacy, cost, risks and their rate of mitigation, argues a new editorial published in Nature Geoscience. With so-called geoengineering proposals proliferating as concerns over climate change mount, Philip Boyd of New Zealand's NIWA warns that "no geo-engineering proposal has been tested or even subjected to preliminary trials". He says that despite widespread media attention, scientists have yet to even come up with a way to rank geoegineering schemes for their efficacy, cost, associated risk, and timeframe. Thus is it unclear whether ideas like carbon burial, geochemical carbon capture, atmospheric carbon capture, ocean fertilization, cloud manipulation, "space sunshades", or strategically-placed pollution can be effective on a time-scale relevant to humankind, economical, or even safe.


Shell Oil funds "open source" geoengineering project to fight global warming

(07/21/2008) Shell Oil is funding a project that seeks to test the potential of adding lime to seawater as a cost-effective way to fight global warming by sequestering large amounts of carbon dioxide in the world's oceans, reports Chemistry & Industry magazine.


Geoengineering solution to global warming could destroy the ozone layer

(04/24/2008) A proposed plan to fight global warming by injecting sulfate particles into Earth's upper atmosphere could damage the ozone layer over the Arctic and Antarctic, report researchers writing in the journal Science.


Geoengineering cure for global warming could cause problems

(08/14/2007) Proposed geoengineering schemes to reduce global warming may do more harm than good, warns a new study published in Geophysical Research Letters.


Geoengineering could stop global warming but carries big risks

(06/04/2007) Using radical techniques to ,engineer, Earth's climate by blocking sunlight could cool Earth but presents great risks that could well worsen global warming should they fail or be discontinued, reports a new study published in the June 4 early online edition of The Proceedings of the National Academy of Sciences.


Modifying clouds to fight global warming

(08/15/2005) An article in The Sunday Times reports that a scientist is working a cloud manufacturing technique to counter global warming.




CITATION:
Jeremy Hance
mongabay.com (January 27, 2010).

Scientists call for research on geoengineering scheme to block sunlight.

http://news.mongabay.com/2010/0127-hance-srm.html