Royal Society Paints Grim Picture of 4°C Temperature Rise


Drought and desertification could be widespread within 50 years. Photo: John Brawley/Creative Commons.

With no doubt intentional perfect timing as the COP16 climate talks open in Mexico, the Royal Society has released a special issue on the future impacts of climate change and, as you might imagine if you've been following the climate research to date, the outlook is entirely grim for many of the planetary systems upon which humans are utterly dependent. As The Guardian puts it, the Royal Society describes a "hellish vision of a world warmed 4C within a lifetime."
Many of the articles in the special issue are open access (at the link above), and TreeHugger has covered many of the topics before, but here's the gist of what failure to reduce emissions sufficiently to keep global average temperature rise means:

First of all, as one of the papers puts it, there's "little to no chance" of keeping the ongoing rise in global surface temperatures below 2°C doing things the way we have been and even the old target of 2°C is no longer considered enough to prevent "extremely dangerous climate change."

By perhaps as soon as 2060, and likely by 2070 at the latest, temperature rise will pass 4°C above pre-industrial levels. By that time,

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.

Though temperature increases will affect the whole world, with regional increases of up to 8°C possible over southern Europe and North Africa, in sub-Saharan Africa things could well be particularly bad (the emphasis in this quote is from Climate Progress, which has a typically thorough overview of the research),

The prognosis for agriculture and food security in SSA in a 4C+ world is bleak. Already today, the number of people at risk from hunger has never been higher: it increased from 300 million in 1990 to 700 million in 2007, and it is estimated that it may exceed 1 billion in 2010 . The cost of achieving the food security Millennium Development Goal in a +2C world is around $40-60 billion per year, and without this investment, serious damage from climate change will not be avoided. Currently, the prospects for such levels of sustained investment are not that bright. Croppers and livestock keepers in SSA have in the past shown themselves to be highly adaptable to short- and long-term variations in climate, but the kind of changes that would occur in a 4C+ world would be way beyond anything experienced in recent times. There are many options that could be effective in helping farmers adapt even to medium levels of warming, given substantial investments in technologies, institution building and infrastructural development, for example, but it is not difficult to envisage a situation where the adaptive capacity and resilience of hundreds of millions of people in SSA could simply be overwhelmed by events.

Though the picture of the world we are directly helping to create through lack of action on reducing greenhouse gas emissions is undeniably dark, let's remember that there is still much that can be done to, if not fully avoid some of the worst of climate change, reduce the impact through adaptation both technologically, socially, and culturally.

Here's the full collection of content from the Royal Society: Four degrees and beyond: the potential for a global temperature increase of four degrees and its implications
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More on Global Climate Change:
Copenhagen Accord Commitments Mean 4.2°C Temperature Rise & No More Coral Reefs by 2100
5.2°C Temperature Rise by 2100: New Business-As-Usual Climate Scenario Presented
Prepare For 4 Degree Celsius Rise in Temperature, Top UK Government Scientist Warns

Tags: Global Climate Change | Global Warming Effects | Global Warming Science