"Somewhere, something incredible is waiting to be known" Carl Sagan
sábado, 29 de octubre de 2011
Climate Change - The last of the glaciers
A new analysis of climate change data and the effects of rising levels of the greenhouse gas carbon dioxides suggests that we are at the end of the period in Earth's history during which icy glaciers form. The study further suggests that the effects of rising CO2 levels is delayed by as much as fifty years but global average temperature might be as much as 5 degrees higher than it is today by the year 2100.
Writing in the International Journal of Global Warming, Wojciech Budzianowski of Wrocław University of Technology, in Poland, explains that the thermal response of the Earth's climate to atmospheric greenhouse gases lags behind the rise in concentration of those gases, including carbon dioxide.
The atmospheric concentration of is increasing at the alarming rate of about 2 parts per million by volume per year. At the beginning of the industrial revolution levels were 220 ppmv, today they are around 390 ppmv, the highest they have been in Earth's history for 15 million years. "It is likely that the increased content of carbon dioxide in the atmosphere is one of the major causes of the differences between mean annual temperatures in the late 1800s and those existing today, i.e. about 0.8 degrees," explains Budzianowski. He hopes to elucidate the fundamental mechanisms of global warming and to provide the necessary tools to usefully describe this complex phenomenon, something that is lacking in the current scientific literature.
From his analysis, Budzianowski points out that the self-oscillatory behaviour of past climates that see the periodic build-up and melting of large masses of glaciers in the Arctic and Antarctic regions is no longer valid. The obvious cause being the sudden rise in atmospheric greenhouse gas concentrations that are a much larger thermal trigger than the reflectivity, or albedo, and heat capacity of the Earth or any fluctuations in heat and light from the sun reaching the planet. As such, there will be no build up of ice cover and glaciers in the future, so the cycle is broken.
"Earth is a dynamical system and global warming is a complex dynamical phenomenon. The current paper proposes basic directions in dynamic modelling of global warming that might be useful in projections of future climate evolution," concludes Budzianowski.