LONDON: Evidence from an 800,000-year-old ice core in the Antarctic shows unprecedented atmospheric change due to carbon dioxide and other greenhouse gases, according to scientists who participated in the 10-nation European Project for Ice Coring in Antarctica.
They say air from the oldest ice core has confirmed increase in greenhouse gas carbon dioxide in the atmosphere to levels not seen for hundreds of years.
The scientists had tested samples of these bubbles of air locked in this ice core after drilling it.
Dr Eric Wolff of the British Antarctic Survey and leader of the science team for the Antarctica project, said it is from air bubbles that "we know for sure that carbon dioxide has increased by about 35 per cent in the last 200 years. Before the last 200 years, which man has been influencing, it was pretty steady."
According to the scientists, the natural level of carbon dioxide over most of the past 800,000 years has been 180-300 parts per million by volume (ppmv) of air. But today it is at 380 ppmv.
The scientists participated in a public seminar, "The Antarctic Canary – the human impact on climate change," held as part of the BA Festival of Science in Norwich Monday and discussed the evidence for climate change and possible solutions.
Wolff said the scariest part of it all is that carbon dioxide today is not just out of the range of what happened in the last 650,000 years but already up 100 per cent out of the range. He said measurements of carbon isotopes showed the extra carbon dioxide came from a fossil source, due to increased human activity.
The ice core sample indicated that normally it took 1,000 years for CO2 to increase 30 ppmv. It has risen by that much in the last 17 years alone, Wolff said.
He added, "The rate of change is the most scary thing. We really are in a situation where something's happening that we don't have any analogue for in our records. It's an experiment we don't know the result of."
Wolff says there is nothing to suggest that earth can take care of such increased levels of carbon dioxide. On the contrary, the ice core suggests that the increase in carbon dioxide will definitely give the occupants of earth a climate change that will be dangerous.
The ice core is in a region of the White Continent known as Dome Concordia. It has been drilled out by the scientists working under the project. There are tiny pockets of ancient air locked in this ice core for several millennia and these give researchers an idea of the direct measure of past environmental conditions. They can see past concentrations of gases like carbon dioxide and methane and measure past temperatures by analyzing the presence of isotopes of hydrogen atom.
