Monday, April 11, 2011

Using Earth's past to predict future climate

Many scientists are convinced that Earth's past can provide us with many answers about Earth's future climate, and whether climate change will indeed be as huge threat as many scientists predict it will be.

The latest interesting research comes from the UCLA geoscientists who have studied fossilized mollusks from some 3.5 million years ago. The purpose of their research was to construct an ancient climate record and so gather the clues about the long-term effects of Earth's current levels of carbon dioxide (CO2) emissions, which are a main contributor to ongoing climate change phenomenon.

By studying these fossils scientists discovered that summertime Arctic temperatures 3.5 million to 4 million years ago were about 18 to 28 degrees Fahrenheit warmer compared to temperatures today.

This period in Earth's past had carbon dioxide levels very similar to today levels for thousands of years so this study is a pretty good indicator of how warm will our planet eventually become if CO2 levels are stabilized at the current value of around 400 parts per million.

The results of this study support the predictions that summertime sea ice in Arctic will likely totally disappear in the next 50 to 100 years.

The scientists also pointed out that Earth's poles are warming faster of any place on the planet, and especially the Arctic area. The poles are the most sensitive to increased temperatures because ice cover in polar regions reflects incoming solar radiation to cool Earth which makes poles incredibly sensitive to even the slight variations in climate.

Dr Aradhna Tripati, a UCLA assistant professor in the department of Earth and space sciences and the department of atmospheric and oceanic sciences, explained this by saying that "increase in Arctic temperatures would not only cause the ice sheets to melt but would also result in the exposed land and ocean absorbing significantly more incoming solar energy and further heating the planet."

How were scientists able to measure the temperatures that were present on earth 3,5 millions years ago? They've done this by measuring the isotopic content of oxygen in a combination of fossilized mollusk and plant samples. The mollusk fossils used in this study were collected at Beaver Pond, located in the Strathcona Fiord on Ellesmere Island, at northernmost point of Canada.