< p >我最近读< em >气候政策影响的非线性下降的北极土地永久冻土和其他冰冻圈元素< / em > < / p > < p > < a href = " https://www.nature.com/articles/s41467 - 019 - 09863 - x”rel = " nofollow noreferrer " > https://www.nature.com/articles/s41467 - 019 - 09863 - x < / > < / p > < p >研究冻土的潜在成本估计碳反馈(PCF)和地表反照率反馈(SAF)不同的排放情况,同时考虑到这些反馈的非线性性质。< / p > < p >结论很简单,但我有点困惑这个数字:< / p > < p > < a href = " https://i.stack.imgur.com/2BGn6.png " rel = " nofollow noreferrer " > < img src = " https://i.stack.imgur.com/2BGn6.png " alt = "在这里输入图像描述" > < / > < / p > < p >这是什么让我迷惑:“非线性SAF由海冰的减少和土地雪组件(图2),导致更少的变暖和负面公司变化相比常数遗留SAF(图4 b)。国防委员会,国防委员会部分和鲍起静场景有最大的最大温度增加和减少土地雪和海冰SAF组件,从而给公司最大的负差异。鲍起静的差异是最高几乎无冰的海洋和无雪的土地2200年之后,即使在冬天。零排放,1.5°C, 2.0°C和2.5°C的场景,有小幅度增长,公司对整个时期由于海冰和土地的小山峰雪SAF组件在这个温度范围内(图2)。总的来说,不断遗留SAF为低排放场景似乎合理,但高估了公司对高排放场景根据目前的气候模型(CMIP5),没有明显的临界点(补充图。4)。< / p > < p >非线性SAF可以部分弥补PCF(图4 C)。高排放NDC, NDC部分和鲍起静场景,降低变暖由于非线性响应SAF部分抵消气候变暖由于PCF。鲍起静的效果是最强的场景,从遗产公司价值的变化从正到负开关信号。SAF稍微放大了PCF的低排放场景不断SAF迫使假设仍然有效(零排放,1.5°C, 2.0°C和2.5°C)。这意味着艾玛不包括PCF和假设一个常数C SAF将低估公司在0.1和0.2之间除了最高的排放情况。这些发现源于非线性色散和SAF一直被忽视在气候政策研究到目前为止(补充注5)41、42、43、44岁。" a lead author explains it more simply: "These two components are set to peak for global temperatures within the range covered by the Paris Agreement, but if the climate warms further, the summer and spring sea ice and land snow covers will retreat further north and the albedo feedback will actually weaken. [...] High emissions scenarios, such as the current business as usual trajectory (BaU) -- expected to lead to around 4°C of warming by 2100 and cause by far the highest impacts on ecosystems and societies -- are also included. Under these, the strength of the PCF reaches its peak and does not increase further, while the continued weakening of the SAF gradually cancels the warming effect of the PCF."
https://www.sciencedaily.com/releases/2019/04/190423114027.htm
can someone explain the logic behind this - why does albedo feedback weaken under a high emissions scenario?