Spanish Cave Indicates Glacier Melt Likely to Be Sudden and Quick
15.02.2010 - Atmosphere & Space, Water & Oceans, Ice & Snow, Bi-polar
We are currently living in an ice age that began some 2.6 million years ago. Although this ice age has witnessed some 20 cycles of glacial and interglacial periods over 100,000-year time scales, scientists are still guessing at what triggers the switch in and out of ice ages. However a new study published in Science shows that these changes happen much faster than initially thought. During a visit to a coastal cave on the Spanish island of Mallorca, a team found various layers of calcite, which have been deposited over time as glacial periods have come and gone.
After dating the calcite, the team was then able to conclude that over the course of the last 81,000 years, sea levels had decreased by 1 metre to reach current levels. This would suggest that global temperatures were probably higher than they are today, even there was less CO2 in the atmosphere. The study also shows that the sea levels were changing rapidly in accordance with glacial build-up or retreat, suggesting very fast ice melt rate and build-up during periods when CO2 levels were below current levels. One hypothesis for this might be that the Earth was receiving more solar radiation because of a different axial tilt, which changes periodically.
Although the study refers to only one point of data - from which it is impossible to infer the entire geological story of the Earth - it shows that one of the biggest gaps in climate science is fully understanding the response of major ice sheets such as the ones currently in Greenland and Antarctica to global warming.
