Greenhouse gas was part of the cause of warming even then, long before industrialisation increased the amount of gas clogging the atmosphere, he said. Now ancient Antarctic ice could help predict modern climate change, he said. It is the historical record which constrains our understanding of the climate system. AAD will re-examine a core covering an 80,000 years timespan drilled around 10 years ago at Law Dome, inland from Casey Station. The real question was what made rapid climate changes occur, Morgan said.
Nobody knows, despite the unlocking of some of the secrets of Antarctic ice.
Also, nobody definitely knows how Antarctic ice sheets are responding to global warming and changes in sea level, he said. The West Antarctic ice sheet contains enough ice to raise global sea levels by five to six metres. The entire Antarctic ice is about equivalent to 70 metres of sea level. But new snow was generally compensating for ice loss, leaving the Antarctic in approximate balance between accumulation and outflow of Antarctic ice, Morgan said. If anything, atmospheric warming should initially increase the Antarctic ice sheet through increased snowfall, with the rate of outfall taking thousands of years to react to temperature change, he said.