Nature, 7 December 2022
Ancient DNA frozen in permafrost from northern Greenland reveals that this region was covered in a thriving forest ecosystem around 2 million years ago, a period during which local air temperatures were only several degrees warmer than current conditions. Prior to these findings, it was nearly impossible to reconstruct such ecosystems, since it is rare to find fossils more than one million years old. This study relied on a new technique to reconstruct DNA fragments from frozen permafrost sediments, allowing researchers to uncover samples of life millions of years older than previously possible. The study therefore opens a window into Greenland during the Late Pliocene and Early Pleistocene (3.5-1 million years ago). Rather than the vast ice sheet we see today, Greenland contained a boreal forest filled with trees, shrubs and smaller plants. It provided a home for many animals, including mastodons, reindeer, hares and geese. Notably, these frozen soils show a unique ecosystem of Arctic and warmer-climate species mixed together, with no modern analog. Late Pliocene air temperatures were around 11°C warmer than present, which resembles Greenland temperatures forecast under high warming scenarios unless emissions are reduced. These sediments underscore the importance of reducing emissions to curb rising temperatures, slow Greenland ice loss and preserve modern ecosystem stability.
https://www.nature.com/articles/s41586-022-05453-y
作者：科学写作实习生 海莉·兰德里根, 全球外展主任 艾, 以及 ICCI 主任 帕姆·皮尔森.
Published 12 月. 16, 2022 Updated 12 月. 16, 2022 7:01 下午