今日关注: 地理工程学(geoengineering和全球变暖

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 据美国《连线》杂志报道,本周部分科学家及政府官员将齐聚加利福尼亚州的阿西洛马,商讨地理工程学(geoengineering)在未来是否会对气候变化带来不利影响这一议题。然而,如今事实情况是,为了能够更好的生存,人类在过去已对地球做出了许多地理改造,并且负面效应也已出现。

据悉,人类的文明社会,当前社会的一切繁荣、富强、发展、进步都发生在全新世(Holocene)。全新世开始于1万年前,人类为了更好的生存,不断建设水利、开垦良田、建造城市,并且形成文明。在这个过程中,人类逐渐地对地球进行了各种地理工程改造。全新世对于人类具有十分重要的意义。

如今,人类改造地球会造成何种后果还不得而知,但科学家认为,目前全新世已不复存在,人类目前处于人类世(Anthropocene)。这是一个新的地质纪元,在这个纪元,人类的活动正威胁着地球的自我调节能力。此外,人类此前对地球所做地理工程学改造已出现弊端。

How to Cool the Planet: Geoengineering and the Audacious Quest to Fix Earth's Climate by Jeff Goodell

Only a couple of years ago, geoengineering seemed like science fiction. Some scientists talked about cooling the planet using massive shields to reflect sunlight back into space or by loading the atmosphere with aerosols, but few thought of these planetary-scale projects as real contenders for averting climate catastrophe. But — perhaps because the challenge of mitigation is not fully recognized — geoengineering has gone mainstream. Increasingly, scientists are turning their attention to it: last month at the Asilomar conference centre in Monterey, California, experts met for the first time to consider how the field can be regulated. Meanwhile, governments are holding parliamentary hearings on the subject and venture capitalists are looking to it as an investment opportunity.

“I don't especially want to work on geoengineering. But now that the genie is out of the bottle, I feel I have to,” says climate modeller Raymond Pierrehumbert of the University of Chicago in Eli Kintisch's “Hack the Planet”, one of the first books to cover this burgeoning subject for a popular audience. Though potentially capable of rapidly reducing temperatures, the numerous technologies that come under the geoengineering umbrella would probably have unintended — and potentially disastrous — consequences. Despite its promise and perils, however, geoengineering is a virtual unknown among the general public, so Kintisch's book and another, Jeff Goodell's “How to Cool the Planet”, both published this month, have come at a crucial time. These two fast-paced tours through the science of geoengineering will help inform growing debates about whether governments should fund large research projects into climatic cooling and about how the various methods might be tested.

Both Goodell and Kintisch make it clear that geoengineering is at best a complement to drastic cuts in carbon dioxide emissions. “We have to immediately launch a worldwide program to stop polluting our atmosphere with this surprisingly pernicious trace gas,” Kintisch argues. Most scientists feel much the same, viewing geoengineering strictly as a possible emergency backup plan that should be used only if things get really dire. And because of the risks involved, the idea of doing field trials, especially of technologies for so-called 'solar radiation management' — that is, blocking out sunlight in one way or another — is still contentious among scientists. But Goodell makes a strong argument in favour of at least some limited tests. He tells the tale of Charles Hatfield, a travelling rainmaker who won acclaim across the United States in the early 1900s. When Hatfield tried to bring rain to San Diego and torrential floods ensued, he was hounded out of the city, his reputation in tatters. With geoengineering, writes Goodell, “it might be smart to begin sorting good ideas from bad, lest we fall under the spell of another generation of Charles Hatfields”. That is, if we do the research, then perhaps we'll decide that some methods are best forgotten.