Rare mineral might tell us global warming's state over next two centuries

Washington, Dec 2 : The study of a rare mineral, which can be used to track ancient climates, will help scientists estimate what will be the condition of the world over the next century or two, as global warming begins to crank up the heat.

Binghamton University geologist Tim Lowenstein is doing the study.

Lowenstein and his colleague Robert Demicco at Binghamton University have discovered that nahcolite, a rare, yellowish-green or brown carbonate mineral, only forms on earth under environmental conditions marked by very high atmospheric CO2 levels.

That establishes it as both a marker and a benchmark that can be used by scientists as they consider the likely climatic implications of ever-increasing CO2 levels in our atmosphere today.

More specifically, nahcolite suggests that Eocene warming was concurrent with atmospheric CO2 levels of at least 1,125 parts per million (ppm), which is 3 times the current levels of 380 ppm, but not all that much higher than we can expect on earth in the next 100 years or so given generally accepted scientific projections based on fossil-fuel consumption.

Because CO2 is a forcing factor for climate change, increases in its levels can be directly tied to global warming.

A greenhouse gas, CO2 absorbs radiation that would normally be reflected out of the atmosphere, helping to ramp up temperatures, melt glaciers and significantly alter ocean currents and weather patterns.

As for steep, projected increases in CO2 levels over the next century, Lowenstein thinks that might not be our only cause for concern.

"Right now, we're on a predictable pace. But, there will likely be tipping points, unexpected events that could really change things, so all of a sudden, we may get changes in ocean circulation that we never would have predicted, or the tundra may melt," he said.

"Some unexpected event is going to occur that's going to be more dramatic than the progressive changes that occurred over the last 100 years," he added.

According to Lowenstein, although it is difficult to predict how global temperatures over the coming centuries will compare to the Eocene, the "hothouse" world 50 million years ago should serve as a reminder of what global changes are possible.

ANI