In the summer of 2007, the Arctic melted to a record extent. It then refroze at a record pace in late October and November. The top image shows the ice in mid-November 2007 after refreezing; the bottom in mid-September, at its record low.
Photo: NASA Earth Observatory
A big ice shelf, eight square miles in size, has broken away near Ellesmere Island in the Canadian Arctic. It is the biggest ice shelf to deteriorate since 2005, according to Reuters.
The collapse leaves a once-vast ice shelf at just 11% of its original size. Once 3,500 square miles, it is now 400, and stands as one of many symbols of global warming's impact on the Earth's poles.
But overall, the Arctic is faring better than in 2007, when a record melt left vast stretches of open water in the once-icy north. Earlier predictions that the North Pole would become ice-free this summer seem to have been overly pessimistic, though the degree of melting is still well more than the long-term average.
The seasonal melting of Arctic sea ice is watched closely, because the Arctic has demonstrated the clearest signals of climate change's early impacts. What happens in the Arctic is seen as a harbinger for the dramatic changes that could be in store for lower latitudes.
If all the push-and-pull of scientific observation, prediction and analysis gets confusing, don't fret. Remember the overriding message that scientists agree to: Greenhouse gas emissions from burning fossil fuels is a significant cause of global warming, and climate change is already beginning to have real and negative effects on life on Earth. The consequences of failing to reduce carbon dioxide pollution will be more dramatic weather- and climate-related changes.
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