Áslaug Geirsdóttir

Abstract Future changes in high latitude shrubification are expected to amplify warming. However, the elevational range and climate sensitivity of shrubification is poorly constrained, which hinders our ability to tune Earth system models. Using a sediment record from a high-elevation lake in Iceland (422 m asl), we leverage ancient birch DNA and mean summer air temperature reconstructed from bacterial lipids to constrain the climate sensitivity of highland shrubification.

[2] Proxy-based reconstructions show that Northern Hemisphere (NH) summer temperatures have generally decreased over the past 8 ka, reflecting the regular decline in summer insolation as Earth moved steadily farther from the Sun during NH summer [Wanner et al., 2011, and references therein].