除了其他的答案…这条曲线不是一个好比较地球的“自然”状态,因为它在1880年开始。(工业革命)[1]已经全面展开了一段时间,而这一点是由于煤炭大约一个世纪。每个工厂由煤,每个房子由煤或煤气加热,和每一个光用煤气。即使这样,地球的温度和海平面图没有显著改变。到了二十世纪中期,气候模型安装在过去的数据(被推断一个微型冰河世纪)[2]。没什么大不了的——这样的气候循环,(历史气候记录所示)[3]。除了气候没有表现。而不是自然循环后,观察到数百年来,温度升级图所示。所以气候科学家不得不提高他们的模型覆盖戏剧性的行为“正常”气候的差异,造型气候事件通常只会出现在一场灾难(如大规模火山喷发)[4]。 The result is that [with all this work, they can predict][5] a lot of the causes and effects of rising global temperatures due to fossil fuel usage (amongst other things). Your friend needs to not just look at the graph of what the Earth is currently doing, but also consider what climate scientists even as far as the 1970s who looked at the historical record were expecting the Earth to do, which assumed not burning stuff. Even then, the Earth will survive. The idea of "saving the Earth" is nonsense - the Earth will survive. Many species will go extinct, but that's happened a lot in the past too. Many major cities (and some entire countries) will be lost too, which is more of an issue for humans. The question is whether your friend is prepared to accept humans having control over whether this happens or not. [1]: https://en.wikipedia.org/wiki/Industrial_Revolution [2]: https://en.wikipedia.org/wiki/Global_cooling [3]: https://en.wikipedia.org/wiki/Milankovitch_cycles [4]: https://www.skepticalscience.com/volcanoes-and-global-warming.htm [5]: https://en.wikipedia.org/wiki/History_of_climate_change_science