In the 70s and 80s, scientists from around the world worked to reconstruct Last Glacial Maximum (19,000 to 23,000 years ago) sea surface temperatures across the globe under the auspices of the Climate: Long Range Investigation, Mapping and Prediction (CLIMAP) project. Since then, a number of new proxies and seafloor coring and drilling projects have produced a wealth of additional data. In a new paper online this week in Nature Geoscience (subscription required), the MARGO (Multiproxy Approach for the Reconstruction of the Glacial Ocean surface) team members have updated this reconstruction using all the newly available data.
The group compiled thousands of data points to create detailed maps of sea surface temperatures for the Last Glacial Maximum. Unlike the CLIMAP results, the MARGO reconstruction shows a 1 to 4º cooling in the tropics. But, despite this tropical chill, the team also found strong east to west gradients in the tropical oceans, as well as the North Atlantic Ocean. Interestingly, this gradient has never been shown in model simulations of the Last Glacial Maximum.
In addition to providing an important reconstruction of Earth’s oceans at the coldest point of the last glacial period, the data provides an important test for the general circulation models used to recreate past conditions. Overall, this new reconstruction provides an important resource for anyone hoping to investigate changes in climate over the past 23,000 years.
Alicia Newton is an associate editor with Nature Geoscience