8,000-year record of climate change

An international team of researchers has found that the Antarctic Ice Sheet plays a major role in regional and global climate variability - a discovery that may also help explain why sea ice in the Southern Hemisphere has been increasing despite the warming of the rest of the Earth. The Antarctic Ice Sheet has experienced much greater natural variability in the past than previously anticipated. Michael Weber Results of the study, co-authored by Michael Weber, a paleoclimatologist and visiting scientist at the University of Cambridge, along with colleagues from the USA, New Zealand and Germany, are published this week . Global climate models that look at the last several thousand years have failed to account for the amount of climate variability captured in the paleoclimate record, according to lead author Pepijn Bakker, a climate modeller from the MARUM Center for Marine Environmental Studies at the University of Bremen in Germany. The researchers first turned their attention to the Scotia Sea. 'Most icebergs calving off the Antarctic Ice Sheet travel through this region because of the atmospheric and oceanic circulation,' explained Weber. 'The icebergs contain gravel that drop into the sediment on the ocean floor - and analysis and dating of such deposits shows that for the last 8,000 years, there were centuries with more gravel and those with less.' The research team's hypothesis is that climate modellers have historically overlooked one crucial element in the overall climate system.