New research shows that both Antarctica and the Arctic are getting less icy – and the best explanation is mankind’s emissions of greenhouse gases.
But will that convert anyone who doubts that global warming is caused by human activities, led by burning fossil fuels?
The scientists, writing in the journal Nature Geoscience, say that a study of temperature records from Antarctica (there aren’t many of them) shows a slight rising trend over recent decades that can be best explained by a build-up of greenhouse gases led by carbon dioxide.
Antarctica had until now been the only continent where a human fingerprint of warming had not been detected by scientists — that meant some sceptics said it might not be global at all.
Ice around the frozen continent has tended to expand in recent years — some climate experts have theories to explain that that could be a side-effect of warming linked to shifting ocean currents or changes in snow and rainfall.
But more ice obviously doesn’t sound a convincing argument for global warming when a runaway melt of the summer sea ice in the Arctic — to a record low in September 2007 – is often held up as Exhibit A in the evidence for climate change.
The U.N. Climate Panel said last year that it was at least 90 percent certain that most of the global warming in the past half century was caused by human activities. Ten percent is room for doubt, but it seems to be shrinking.