Actu-environment, 02 / 05 / 05 by CS
A team of researchers led by James Hansen, director of space studies at NASA's Goddard Institute, the US Space Agency, has calculated that Earth retains 0,85 watt (+/- 0,15) more energy per square meter than it did not emit on a given period whereas this figure was only a few tenths of Watt before 1960. These results were published Thursday in Science Express.
According to James Hansen, author of the article, this imbalance of energy is the index showing that scientific estimates of the impact of human activity on climate are very accurate.
These calculations have been accomplished using oceanographic computer models and climatological stations installed on buoys on the oceans or in ground stations whose data are collected by satellites. According to his data, the ocean level has already increased by 3,2 centimeters since 1993 and although this variation seems minimal, it is actually twice as large as that recorded over the whole of the last century.
In addition, the oceans keep the heat longer than the ground and act as thermal accumulators with a phenomenon that occurs in the oceanic depths, and called "thermal inertia".
This means that if we stop anthropogenic greenhouse gas emissions completely we can expect a rise of 0,6 degrees Celsius.
In other words, the author makes it clear in his introduction that the reduction of GHG emissions must be undertaken promptly and that if the world decides to have more evidence of global warming before acting, the phenomenon of thermal inertia oceans suggests even greater climate change that will be exceedingly difficult or impossible to avoid.