经济学人下载:IPCC土地使用报告(1)

After 29 hours of uninterrupted negotiations the latest report from the Intergovernmental Panel on Climate Change (IPCC),
29个小时的无间断谈判后，8月7日下午，政府间气候变化专门委员会（IPCC）关于

on how alterations in land use are contributing to such change, was gavelled through in Geneva on the afternoon of August 7th.
土地使用的改变如何促成这种变化的最新报道在日内瓦通过。

When, minutes later, your correspondent asked to speak with some of the researchers, she was informed they had "gone to bed".
几分钟后，当记者要求采访研究人员时，她被告知他们已经“上床睡觉了”。

The report these exhausted delegates produced—all 1,300 pages of it—
这些精疲力尽的代表们的这份报告—共1300页—

fires another warning shot about the state of the planet and the way people are transforming virtually every corner of every continent.
对地球现状以及人们改变几乎每个大陆每个角落的方式发出了另一个警告。

Human activities affect roughly three-quarters of Earth's ice-free land, with huge consequences for the climate.
人类活动对影响到了地球约四分之三的非冰覆陆地，对气候也产生了巨大影响。

Land masses are natural carbon sinks, absorbing greenhouse gases by a variety of processes, including photosynthesis.
大陆块是天然的碳汇，通过各种方式吸收温室气体，包括光合作用。

They also produce such gases—for instance, when vegetation decomposes or burns.
它们也产生气体—如植物分解或燃烧的时候。

By conserving some ecosystems and destroying others to make way for pastures and fields,
通过保护一些生态体系以及破坏其他生态体系为牧草和农田让步

or chopping down trees for timber, human activities on the land add an extra layer of complexity to already complex natural cycles.
或是砍伐树木，陆地上的人类活动为本就复杂的自然循环增加了一层额外的复杂性。

The report found that between 2007 and 2016 such activities produced emissions equivalent to 9bn-15bn tonnes of carbon dioxide each year,
该报告发现在2007年到2016年间，这样的活动每年产生的排放量相当于90亿至150亿公吨二氧化碳，

or roughly 23% of all manmade greenhouse-gas emissions. During that time, land surfaces soaked up 8.6bn-13.8bn tonnes of carbon dioxide.
或是约占所有人为温室气体排放的23%。在此期间，陆地表面吸收了86亿至138亿吨二氧化碳。

At the moment, then, these sinks and sources are roughly in balance.
目前，这些碳汇和碳源大致处于平衡状态。

But climate change, deforestation and agriculture mean the CO2-soaking-up ability of the continents is being depleted.
但气候变化、采伐森林和农耕意味着陆地吸收二氧化碳的能力正在枯竭。

The accelerating destruction of the Amazon forest, which researchers fear may be approaching a point of no return, is of particular concern.
研究人员担心，亚马逊丛林的加速破坏可能将临近不可逆转的地步，这一点让人尤为担忧。

And across the world, depending on the type of husbandry practised,
在世界各地，根据实施畜牧业方式的不同，

farming is eroding soil at a rate between ten times and more than 100 times faster than new soil forms.
农业侵蚀土地的速度是新土壤形成速度的10倍到100多倍。

Climate change, moreover, creates a vicious feedback loop. Higher temperatures promote the degradation of land through drought,
此外，气候变化创造出了一个恶性反馈循环。更高的温度促使土地因干旱、

desertification and rising seas, and the promotion of wildfires like the ones currently blazing in Alaska, Siberia and Greenland.
沙漠化和海平面上升以及像目前在阿拉斯加、西伯利亚和格陵兰那样燃烧的野火而退化。