中英对照：污染减少意味着亚马逊雨林更多干旱

　　Declining aerosol pollution could make severe drought in the Amazon rainforest more common in the twenty-first century, report scientists in Nature today (8 May).

　　英国和巴西的科学家使用了数学模型来模拟气候变化对亚马逊地区降雨量变化的影响。他们把2005年亚马逊西部出现的严重干旱作为参考点，这是过去100年来最严重的干旱之一。

　　British and Brazilian researchers used mathematical models to simulate the effect of climate change on rainfall variation in the Amazon. They used the severe drought in the western Amazon in 2005 — one of the most severe in the last 100 years — as a reference point.

　　2005年的干旱（参见 亚马逊干旱“可能加剧气候变化”）与北大西洋海洋表面温度异常变暖有关，这种高于南大西洋的变暖导致了降雨量减少。

　　The 2005 drought (see Amazon drought 'could worsen climate change') was associated with sea surface temperatures in the North Atlantic being unusually warm compared with the South Atlantic, which led to decreased rainfall.

　　这组科学家模拟了预计的气候变化，包括了诸如二氧化碳浓度和大气气溶胶等因素，结果发现这样的大西洋温度梯度很可能变得更加常见。

　　The scientists' simulations of projected climate change, which included factors such as carbon dioxide concentrations and atmospheric aerosols, found that such Atlantic temperature gradients are likely to become more common.

　　这是由于北半球煤炭燃烧的减少已经减少了二氧化硫气溶胶的排放。这些二氧化硫对气候具有致冷效应，清除这种效应将使北大西洋相对于南大西洋的海洋表面温度增加。

　　This is because a decline in coal burning in the Northern Hemisphere has reduced emissions of sulphur dioxide aerosols. These have a cooling effect on the climate, and removing this effect will increase the sea surface temperature in the North Atlantic relative to the South Atlantic.

　　根据这个模型，2005年干旱时遇到的情况大约是20年1遇的事件，但是到2025年将变成2年1遇，到2060年变成10年9遇。

　　According to the model, the conditions surrounding the 2005 drought were approximately a 1-in-20-year event, but will become a 1-in-2-year event by 2025, and a 9-in-10-year event by 2060.

　　该研究的第一作者Peter Cox是英国埃克塞斯大学教授、英国气象局气候系统动力学主任。他告诉本网站说：“气溶胶污染可能导致酸雨，而低浓度的气溶胶颗粒通常对空气质量不利——也对人类健康不利。因此减少这类污染是正确的。”

　　Lead author Peter Cox holds the Met Office chair in Climate System Dynamics at the University of Exeter, UK. He told SciDev.Net, "Aerosol pollution can lead to acid rain, and low-level aerosol particles are generally bad for air quality — and therefore human-health. So reducing them is the right thing to do."

　　“然而，随着我们提高空气质量，我们面临着一个更大的挑战——也就是减缓和制止气候变化——因为硫酸盐气溶胶也可以抵消很大一部分由于温室气体而导致的全球变暖。”

　　"However, as we clean-up air quality, we face a bigger challenge — to slow-down and halt climate change — because sulphate aerosols have also offset a large-part of the global warming from greenhouse gases."

　　此前的研究表明气溶胶污染的降低将影响全球气候变化的速率。这项新的研究解释了为什么这尤其会对亚马逊雨林造成问题。

　　Previous studies have shown how falling aerosol pollution will affect the rate of global climate change. The new study explains why this is especially an issue for the Amazon rainforest.

　　论文的作者之一、巴西国立太空研究所的José Marengo补充说：“我们的研究证实了亚马逊地区的干旱可能变得更加频繁。重申需要减少二氧化碳的排放，这是非常重要的。”

　　"Our study confirms that Amazonian droughts can be more and more frequent. It's very important to reaffirm the need for reducing carbon dioxide emissions," adds co-author José Marengo, of the Brazilian National Institute for Space Studies.

　　本文由科学与发展网络(SciDev.Net)独家提供。