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Geoengineering could save Earth, or destroy it

Dec. 4, 2011 - 11:19 By

DURBAN, South Africa (AP) -- Brighten clouds with sea water? Spray aerosols high in the stratosphere? Paint roofs white and plant light-colored crops? How about positioning ``sun shades'' over the Earth?

At a time of deep concern over global warming, a group of scientists, philosophers and legal scholars examined whether human intervention could artificially cool the Earth _ and what would happen if it did.

A report released late Thursday in London and discussed Friday at the U.N. climate conference in South Africa said that _ in theory _ reflecting a small amount of sunlight back into space before it strike's the Earth's surface would have an immediate and dramatic effect.

Within a few years, global temperatures would return to levels of 250 years ago, before the industrial revolution began dumping carbon dioxide into the air, trapping heat and causing temperatures to rise.

But no one knows what the side effects would be.

They could be physical _ unintentionally changing weather patterns and rainfall. Even more difficult, it could be political _ spurring conflict among nations unable to agree on how such intervention, or geoengineering, will be controlled.

The idea of solar radiation management ``has the potential to be either very useful or very harmful,'' said the study led by Britain's Royal Society, the Washington-based Environmental Defense Fund and TWAS, the academy of sciences for the developing world based in Trieste, Italy.

Environmentalist Silvia Ribeiro, of the Canada-based ETC-Group, said geoengineering should be outlawed before it gets off the ground.

``Solar radiation management technologies are high-risk and extremely dangerous and they should be treated under international law like nuclear weapons _ except, unlike nuclear weapons, we have an opportunity to ban their testing and their proliferation before the technology is fully developed, rather than trying to prevent their proliferation after the fact,'' she said.

The final report grew out of three days of talks in a quiet country retreat last March, the climax of a yearlong dialogue spanning experts in 22 countries.

It was prompted in part by the failure of a 20-year U.N. negotiating process to take decisive action to curb greenhouse gas emissions, mainly from burning fossil fuels, responsible for climate change.

``The slow progress of international climate negotiations has led to increased concerns that sufficient cuts in greenhouse gas emissions may not be achieved in time to avoid unacceptable levels of climate change,'' the report said.

But geoengineering is not an alternative to climate action, said John Shepherd, a British oceanographer from the University of Southampton who was a lead author of the report.

``Nobody thought this provides a justification for not reducing carbon emissions,'' Shepherd said in a telephone interview from London.

``We have to stick with Plan A for the time being, and that could be a very long time indeed,'' he said. ``This would buy time for people to make the transition to a low-carbon economy.''

The Intergovernmental Panel on Climate Change foresees temperatures rising as much as 6.4 degrees Celsius (11.5 degrees Fahrenheit) by 2100, swelling the seas with melted glacial water and disrupting climate conditions around the globe.

Releasing millions of tons of sulfur dioxide in the upper atmosphere would mimic the cooling effects of a volcanic eruption, lowering global temperature about 0.5 Centigrade (0.9 Fahrenheit), which can last for a year or two when it occurs naturally.

But deliberately tinkering with nature to counter global warming can only be a stopgap measure, and is fraught with danger, the report said.

Action such as spraying sulfur into the air or brightening clouds with sea water to reflect more sunlight would have to be sustained indefinitely because ``there would be a large and rapid climate change if it were terminated suddenly,'' the report said.

Hazy skies could alter weather patterns and agriculture, replacing one source of climate change with another.

Years of study are required to calculate the environmental impacts, but the bigger questions are political.

Who would decide where and when to conduct experiments, and where to set the global thermostat? What would happen if a country acted on its own without an international agreement? Would it discourage efforts to reduce reliance on fossil fuels and reduce carbon emissions?

Notions of manipulating the climate to impede global warming have been on the fringe of scientific discussion for some time, but is moving increasingly toward the mainstream.

In the United States, a group of 18 U.S. experts from the sciences, social sciences and national security unveiled a report in October urging the federal government to begin research on the feasibility and potential effectiveness of geoengineering.

``The United States needs to be able to judge whether particular climate remediation techniques could offer a meaningful response to the risks of climate change,'' said that report sponsored by the Bipartisan Policy Center.

Shepherd said the 65-page Thursday's report was intended to start the conversation.

``No government asked us to do this. The U.N. didn't ask us,'' he said.

``I hope it can be continued in a more formal and mandated framework, because eventually somebody will have to take some decisions.''

 

<한글기사>

'기후조작으로 수년내 지구냉각 가능'

인간이 대규모 기후 조작에 나서면 몇 년 만에  지구온난화를 되돌릴 수 있을 것으로 예측됐다.

그러나 인위적인 '기후 개입'은 큰 부작용을 초래할 수 있다는 우려도 함께  제 기됐다.

영국왕립학회, 미국 워싱턴 소재 환경보호기금(EDF), 이탈리아 트리에스테 소재

개발도상국과학한림원(TWAS) 공동 연구진은 1일 이런 내용을 담은 지구공학(geoengi

neering) 보고서를 공개했다.

자연과학과 철학, 법학 등 관련 분야 전문가들이 참여한 이 보고서는 더반에서 열리고 있는 '제17차 유엔기후변화협약 당사국총회'에서 2일 논의된다.

유엔의 공식 견해에 따르면 기후변화에 따라 2100년까지 지구상의 평균온도는 약 6.4℃가 상승하며 이로 인해 해수면 상승 등 엄청난 환경재난이 일어날 것으로 우려된다.

지구공학이란 화학·물리적 방법을 동원해 기후변화를 차단하는 이론적  가능성 을 연구하는 분야를 가리킨다.

예를 들어 이산화황 수백만t을 대기권 상층부에 살포하거나 해수를 분무해 구름 의 색을 더 밝게 만들어 태양광의 반사율을 높여 지표면에 도달하는 에너지를  줄임 으로써 온도상승을 막을 수 있다는 것이다.

간단하게는 지붕을 모두 옅은 색으로 칠한다든지, 밝은 색 작물을 재배한다든지 하는 방법도 거론된다.

연구진의 시뮬레이션 결과 지구공학적 방법을 시행하면 단 몇 년 안에 산업혁명 이전 수준으로 지구온도를 떨어뜨리는 극적인 효과를 발휘할 수 있는 것으로 나타났 다.

이산화황 살포법은 단번에 평균온도를 0.5℃ 낮출 수 있다.

그러나 인위적인 '지구 냉각'은 인간에 의한 기후교란 등 큰 부작용을 초래할 수 있다고 연구진은 경고했다.

지구공학은 아직은 이론적 논의 단계지만, 실행 가능성에 대한 논의가 점차  활 발해지고 있다.

연구를 주도한 존 셰퍼드 사우샘프턴대 교수(해양학)는 "(온실가스 배출을 최소

화하는) 플랜A를 실천하는 데 최선을 다해야 한다"면서도 "지구공학이 저탄소  경제 로 이전하기까지 시간을 벌어줄 수 있다"고 주장했다.