Tuesday, November 30, 2010

Where did the global warming go?

Despite the amazing snow we've been getting in Edinburgh, globally this year is currently tied in first place and is on track to be at least in the top three hottest years on record. More national highest temperatures have been set this year than any previous year. Indeed, ironically the impressive snow (by local standards) received in the UK this year and last year is linked to unusual wind patterns in the Arctic creating a phenomenon dubbed "WACCy weather" - Warm Arctic Cold Continents. Warmer temperatures in the Arctic and over Greenland block the prevailing westerly winds and instead lead to frigid air descending on the UK from the north and north-east.

The Arctic climate is warming faster than anywhere on earth so we might well see more of this pattern in future. This is why it is important to think in terms of climate change and not simply global warming (which is one, often misunderstood, feature of climate change).

Why does this matter? Because within my daughter's lifetime (if she manages to stay healthy), our current climate trajectory could well lead to a billion people losing their homes and three billion losing access to clean water. On our current path, we are headed well beyond a rise of 2ºC and to more than 4ºC by the end of this century, which is likely to mean droughts beyond anything in human memory covering large parts of the globe while other parts flood, millions of refugees, dire crop reductions and the social and political instability these would likely bring.

"In such a 4°C world, the limits for human adaptation are likely to be exceeded in many parts of the world, while the limits for adaptation for natural systems would largely be exceeded throughout the world."

- Rachel Warren, “The role of interactions in a world implementing adaptation and mitigation solutions to climate change”, Phil Trans R Soc A 13 January 2011 vol. 369 no. 1934 217-241.

It doesn't have to be this way.


byron smith said...

4ºC and what it means, from here:
"Rachel Warren, at the University of East Anglia, described a 4C world in her research paper: “Drought and desertification would be widespread … There would be a need to shift agricultural cropping to new areas, impinging on [wild] ecosystems. Large-scale adaptation to sea-level rise would be necessary. Human and natural systems would be subject to increasing levels of agricultural pests and diseases, and increases in the frequency and intensity of extreme weather events.”

"Warren added: “This world would also rapidly be losing its ecosystem services, owing to large losses in biodiversity, forests, coastal wetlands, mangroves and saltmarshes [and] an acidified and potentially dysfunctional marine ecosystem. In such a 4C world, the limits for human adaptation are likely to be exceeded in many parts of the world.”

"Another Met Office study analyses how a 4C rise would differ from a 2C rise, concluding that threats to water supplies are far worse, in particular in southern Europe and north Africa, where regional temperatures would rise 6-8C. The 4C world would also see enhanced warming over most of the US, Canada and northern Asia.

"In sub-Saharan Africa (SSA), “the prognosis for agriculture and food security in a 4C world is bleak”, according Philip Thornton, of Kenya’s International Livestock Research Institute, who led another research team. He notes there will be an extra billion people populating Africa by 2050."

byron smith said...

32cm more snow in Edinburgh today.

byron smith said...

James Hansen on Europe's recent cold snap.

byron smith said...

Another good explanation of why it is so cold in Europe at the moment.

byron smith said...

A new study further explains the causes of this WACCy weather.

See also Monbiot's explanation here.

byron smith said...

And a more in-depth explanation here (with lots of photos and charts).

byron smith said...

And an excellent reply by Michael Northcott to Bob Ward on the Crisis Forum.

byron smith said...

And an explanation from NOAA.