Global warming, uneven changes across planet

melting sea ice
With greater melting of the sea ice, polar bears (above, off northern Alaska in 2007) find hunting for prey hard. Photograph: Dan Crosbie/PA

March 7, 2016 — Less than 2°C of global warming for the Earth, the target agreed by leaders at the COP21 climate conference in Paris last November, doesn’t really sound too ambitious. In fact, many of us would welcome an extra couple of degrees warmth. So what is all the fuss about?

Unfortunately the warming would not occur evenly around the world. A study published recently in Nature shows what 2°C of warming – a rise, of this level, above the pre-industrial global mean surface temperature – might really feel like and which regions may be hit hardest.

Some of the regional hot spots cited are the Mediterranean countries, Brazil and the US, where 2°C of global warming could translate into local temperature increases of more than 3°C. But the region expected to suffer most is the Arctic, where night-time temperatures are predicted to soar by 6°C.

“Some countries are much more exposed than others,” says Rob Wilby, from Loughborough University.

The Earth has already warmed by an average of 1°C, and the uneven nature of this warming is becoming clear with Arctic regions already beyond the 2°C mark. Meanwhile, climate models suggest that the Mediterranean could pass the 2°C level once global temperatures have risen by 1.4°C.

Oceans, which cover 70% of the planet, warm much more slowly than land and are partly responsible for the uneven pattern of warming. Local factors, like loss of heat-reflecting snow in the Arctic, make a difference, too.

And it isn’t just temperature: changes in rainfall are also expected to be unequally distributed, with most land areas getting more of a dousing, according to the researchers. “Recent flooding episodes in the UK give us an insight into just how vulnerable we are,” says Wilby.

guardian_64  by Kate Ravilious | The Guardian