Almost all of the Earth’s glaciers are retreating and areas that were covered in ice last century are now bare. This is the most visible effect linked to global warming.
This movement is caused by the dynamic structures of glaciers. Every summer, part of their ice disappears and every winter new ice forms. Depending on the assessment, the glacier is retreating (shrinking) or advancing (growing). The two phenomena depend directly on temperature and because of global warming, our planet’s glaciers have retreated by an average of almost 500 metres compared to the beginning of the industrial era. They are not only retreating but also becoming thinner. Over the past few years, glaciers have lost 230 billion tons of ice a year!
Two cases, Antarctica and Greenland, are particularly important because their icecaps contain 99% of the Earth’s ice. In the first case, with temperatures that go down to -70 °C in winter in the South Pole, the ice is not likely to disappear in the foreseeable future. But Antarctica is an immense continent with areas that are very different from each other. In some areas, for local reasons, snow cover is increasing slightly. In others, especially in the West (near Argentina and Chile), glaciers are indeed melting. But, for the moment, the continent has not shown marked changes due to global warming.
In Greenland, the situation is much more worrying. Just recently, researchers thought that it would only suffer the effects of global warming moderately. This does not seem to be the case. Over the past few years, Greenland’s ice has been melting much faster than predicted.
The fate of glaciers and icecaps depends on greenhouse gases that are sometimes produced millions of miles away in Paris, Beijing or Los Angeles. Their evolution therefore shows the global nature of the phenomenon. This global nature creates a new form of planetary responsibility.