Imagine not a white, but a green Arctic, with woody shrubs as far north as the Canadian coast of the Arctic Ocean. This is what the northernmost region of North America looked like about 125,000 years ago, during the last interglacial period, finds new research from CU Boulder led by Sarah Crump. Researchers analyzed plant DNA more than 100,000 years old retrieved from lake sediment in the Arctic and found evidence of a past ecosystem. As the Arctic warms much faster than everywhere else on the planet in response to climate change, the findings, published this week in the Proceedings of the National Academy of Sciences, may not only be a glimpse of the past but a snapshot of our potential future.