地球上哪些物種，有可能逃脫氣候災(zāi)難而存活下來？

“I don’t think it will be the humans. I think we’ll go quite early on,” says Julie Gray with a laugh. I’ve just asked Gray, a plant molecular biologist at the University of Sheffield, which species she thinks would be the last ones standing if we don’t take transformative action on climate change. Even with our extraordinary capacity for innovation and adaptability, humans, it turns out, probably won’t be among the survivors.

我問謝菲爾德大學(xué)的植物分子生物學(xué)家朱麗·格雷，如果人類不對氣候變化危機采取徹底行動，她認為地球上哪些物種將有可能逃脫氣候災(zāi)難而存活下來。她大笑著回答我，“我認為不會有人類在內(nèi)。我們?nèi)祟悤辉鐪缤觥?rdquo;即使人類有巧奪天工的非凡創(chuàng)造力和適應(yīng)力，但可能也無法成為幸存者。

This is partly because humans reproduce agonisingly slowly and generally just one or two at a time – as do some other favourite animals, like pandas. Organisms that can produce many offspring quickly may have a better shot at avoiding extinction.

部分原因是人類繁殖后代的速度實在太慢，通常人一生只能養(yǎng)育繁殖一兩個后代，類似一些特別受人類青睞的動物，比如熊貓。具備快速生殖大量后代能力的生物逃過滅絕的幾率較高。

It may seem like just a thought experiment. But discussing which species are more, or less, able to survive climate change is disturbingly concrete. As a blockbuster biodiversity report stated recently, one in every four species currently faces extinction. Much of this vulnerability is linked to climate change, which is bringing about higher temperatures, sea level rise, more variable conditions and more extreme weather, among other impacts.

這看來只是一個臆想實驗。但有關(guān)地球各物種逃過氣候變化而生存下來幾率大小的討論，卻是令人不安的。最近一份引起各方重視的的生物多樣性報告聲稱，目前地球上每四個物種中就有一個面臨滅絕之災(zāi)。地球生物今天如此之脆弱，很大程度與當(dāng)今的氣候變化有關(guān)。氣候巨變造成氣溫升高、海平面上升，而且出現(xiàn)更多極端反常的天氣。

Some caveats are in order. While the seriousness of climate change is undeniable, it’s impossible to know exactly how those effects will play out for species vulnerability, especially far into the future. Methods of forecasting vulnerability are ever evolving, while limited and inconsistent data, plus the complex interactions of policies, land-use changes, and ecological effects, mean that projections aren’t set in stone. Climate change vulnerability assessments have had biases and blind spots (just as humans do more generally).Moreover, the indirect effects that are responsible for many climate change impacts on populations, such as in the food chain, are more complex to model than direct effects.

必須發(fā)出一些警告。雖然無人否認氣候變化會帶來嚴重后果，但也無人能精確認識氣候變化將如何影響物種的脆弱性，尤其是在遙遠的未來。預(yù)測哪些物種難以經(jīng)受氣候變化沖擊的方法在不斷進展，不過預(yù)測獲得的數(shù)據(jù)卻很有限，而且有矛盾之處。加上政策、土地使用變更和生態(tài)影響之間復(fù)雜的交互作用，意味著預(yù)測并非很準確，并非不需修改。就像人類通常的行為一樣，人類對易受氣候變化沖擊物種的評估也存在偏見和盲點。此外，還有一些引起不少氣候變化的間接因素，也對物種數(shù)量產(chǎn)生影響，例如生物食物鏈方面的影響，這比氣候的直接影響更難以建立預(yù)測模式。

Another source of uncertainty has to do with life forms’ capacity to adapt. Take ectotherms (cold-blooded animals like reptiles and amphibians), which have historically been slower to adapt to climatic change than endotherms. For one thing, they are less able to adjust their body temperatures. But there are exceptions, like the American bullfrog, which may actually find more habitable environments as a consequence of warming.

另一個不確定性因素與物種的生命適應(yīng)能力有關(guān)。以爬行動物和兩棲動物所屬的變溫動物或冷血動物為例，這些變溫動物在演化歷史上不如恒溫動物那樣能很快適應(yīng)氣候的變化。原因之一是，變溫動物無法調(diào)整自己的體溫。不過也有例外，比如美洲牛蛙，可能更適應(yīng)氣候變暖的棲息地。

And, of course, there is an alternative: we humans could get our acts together and stop the climate crisis from continuing to snowball by adopting policies and lifestyles that reduce greenhouse gases. But for the purposes of these projections, we’re assuming that’s not going to happen.

當(dāng)然，地球物種的命運也有另一種選擇，但這要取決于人類。如果我們?nèi)祟惾f眾一心，采取措施，改變生活方式，減少溫室氣體的排放，就可以阻止氣候危機像滾雪球一樣地急速下滑加劇。但我們在預(yù)測不同物種受氣候暖化沖擊的回應(yīng)和結(jié)局時，是假設(shè)這沒有發(fā)生。