VOA标准英语2011--Study: Reducing Soot is Fastest Way to S

Study: Reducing Soot¹ is Fastest Way to Slow Climate Change

A new study finds that reducing carbon-rich soot emissions² could be the fastest and most economical way to slow climate change and protect human health.
Those dust-like particles released in the exhaust of diesel³-powered vehicles and wood fires rank second only to carbon dioxide as a major cause of global warming.
Stanford University professor Mark Jacobson developed the first computer models to measure the presence of soot in the atmosphere. He calculates that soot accounts for between 15 and 20 percent of global warming.
His study, presented this week at the American Chemical Society meeting in Colorado, describes how black carbon - the main component⁴ in soot - heats up clouds when it mingles⁵ with the rain drops suspended within them.
“And it turned out that there is more heating when the black carbon was inside the drop than between the drops and there was more heating when the black carbon was between the drop than outside of the cloud. So the bottom line was you get this enhancement of the heating of the cloud by the black carbon presence in the cloud drops.”
Jacobson says climate models that ignore this cloud absorption phenomenon underestimate the effects of black carbon in the atmosphere. His research found that airborne soot quickly burns off cloud cover.
“If you look at satellite images over really polluted areas such as in China and India you can actually see an absence of clouds.”
While carbon dioxide can remain in the atmosphere for 40 or 50 years, carbon soot stays around only for a week or 10 days before settling out, and has no continuing warming effect.
“Soot is a solar absorber, whereas carbon dioxide is primarily a heat absorber. Now, per unit mass, black carbon is about a million times more powerful in warming the air than is carbon dioxide. But because soot, black carbon in soot, are so powerful and warming and because they are very short-lived, that is actually important for control strategies for global warming.”
Case in point: The Arctic is warming faster than anywhere on the planet. The white sea ice, which normally reflects sunlight and heat back into space, is giving way to darker areas of open water, which absorbs heat faster, and so accelerates the warming. The Arctic could be ice free within 30 years, according to recent studies.
Jacobson says reducing the amount of soot in the atmosphere can reverse this trend. “And you can slow down the loss of the Arctic ice. And so it may be the only way to prevent or slow down the elimination⁶ of the Arctic. And that has implications, of course, not only for climate feedbacks, but also for wildlife such as polar bears which rely on ice floes to survive.”
Jacobson says technology exists to address the problem. Wood burning cooking and heating devices - used widely in the developing world - can be upgraded to burn more cleanly. We can switch away from diesel fuels, or use more efficient, low-emission diesel engines.
And there are other measures that can help reduce the volume of soot released into the atmosphere. “You can certainly put on particle traps on vehicles, off road equipment, passenger vehicles and buses, trucks. But in terms of controlling CO2 and soot, which I think really we want to do, it is really changing the energy infrastructure⁷ and the vehicle infrastructure.”
That would mean a move to electric or hydrogen vehicles, powered by clean energy sources. Jacobson says that with concerted national and international efforts, soot levels in the atmosphere could be reduced by 90 percent in five to 10 years.

1 soot   

n.煤烟，烟尘；vt.熏以煤烟

参考例句：

• Soot is the product of the imperfect combustion of fuel.煤烟是燃料不完全燃烧的产物。
• The chimney was choked with soot.烟囱被煤灰堵塞了。

2 emissions   

排放物( emission的名词复数 )； 散发物（尤指气体）

参考例句：

• Most scientists accept that climate change is linked to carbon emissions. 大多数科学家都相信气候变化与排放的含碳气体有关。
• Dangerous emissions radiate from plutonium. 危险的辐射物从钚放散出来。

3 diesel   

n.柴油发动机，内燃机

参考例句：

• We experimented with diesel engines to drive the pumps.我们试着用柴油机来带动水泵。
• My tractor operates on diesel oil.我的那台拖拉机用柴油开动。

4 component   

n.组成部分，成分，元件；adj.组成的，合成的

参考例句：

• Each component is carefully checked before assembly.每个零件在装配前都经过仔细检查。
• Blade and handle are the component parts of a knife.刀身和刀柄是一把刀的组成部分。

5 mingles   

混合，混入( mingle的第三人称单数 )； 混进，与…交往[联系]

参考例句：

• He rarely mingles with persons of his own rank in society. 他几乎不与和他身份相同的人交往。
• The distant rumbling of the guns mingles with our marching song. 枪的深邃长声与我们行进歌混合。

6 elimination   

n.排除，消除，消灭

参考例句：

• Their elimination from the competition was a great surprise.他们在比赛中遭到淘汰是个很大的意外。
• I was eliminated from the 400 metres in the semi-finals.我在400米半决赛中被淘汰。

7 infrastructure   

n.下部构造，下部组织，基础结构，基础设施

参考例句：

• We should step up the development of infrastructure for research.加强科学基础设施建设。
• We should strengthen cultural infrastructure and boost various types of popular culture.加强文化基础设施建设，发展各类群众文化。