High-latitude warming initiated the onset of the last deglaciation in the tropics
High-latitude warming initiated the onset of the last deglaciation in the tropics
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DOI：
10.1126/sciadv.aaw2610
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发表时间：
2019-12-01
期刊：
影响因子：
13.6
通讯作者：
Zimmerman, Susan R. H.
中科院分区：
文献类型：
--
作者：
Jackson, Margaret S.;Kelly, Meredith A.;Zimmerman, Susan R. H.
大气温室气体浓度被认为在更新世冰期-间冰期周期期间使全球温度同步，但它们相对于高纬度日照和冰盖范围变化的影响仍然受到很少的限制。在这里，我们使用热带冰川波动来评估相对于全球气候强迫的低纬温度变化的时间。我们报道了热带东非和南美洲的BE-10年龄段的冰川，并表明冰川在全球末次冰盛期达到最大值的时间类似于29~20ka。热带冰川退缩发生在20ka之前，二氧化碳迅速上升的速度接近18.2ka。这种“早期”的热带气候变暖是受两个极地地区高纬度日照上升和一致的冰盖退缩的影响，这降低了经向温度梯度，减少了热带热量向高纬度的输出。
Atmospheric greenhouse gas concentrations are thought to have synchronized global temperatures during Pleistocene glacial-interglacial cycles, yet their impact relative to changes in high-latitude insolation and ice-sheet extent remains poorly constrained. Here, we use tropical glacial fluctuations to assess the timing of low-latitude temperature changes relative to global climate forcings. We report Be-10 ages of moraines in tropical East Africa and South America and show that glaciers reached their maxima at similar to 29 to 20 ka, during the global Last Glacial Maximum. Tropical glacial recession was underway by 20 ka, before the rapid CO2 rise at similar to 18.2 ka. This "early" tropical warming was influenced by rising high-latitude insolation and coincident ice-sheet recession in both polar regions, which lowered the meridional thermal gradient and reduced tropical heat export to the high latitudes.