Climate change is not news to the scientific community, and it’s certainly not news to the UN, which published its fourth Global Environment Outlook report overnight (read the full document here).
What has focussed public attention, and has policymakers scrambling for solutions, is climate events consistent with what is expected under climate change: Europe’s heatwave, America’s hurricanes and fires, Australia’s drought.
Today’s UN Global Environment Outlook report drives home some of the key facts:
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- 11 of the 12 last years were the warmest since 1850;
- Global average temperatures are three quarters of a degree higher than over the past century, and further rise is already locked in;
- 2 degrees is widely seen as a threshold beyond which there is an unacceptable risk of major and irreversible changes in the earth system;
- More, and more intense heatwaves, storms, floods and droughts are expected, along with sea level rise and greater spread of tropical disease;
- The Earth’s surface is warming. This is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level;
- The per capita availability of freshwater is declining globally, and contaminated water remains the greatest single environmental cause of human sickness and death;
- Aquatic ecosystems continue to be heavily exploited, putting at risk sustainability of food supplies and biodiversity;
- The great majority of well-studied species are declining in distribution, abundance or both.
What to do? Put simply, adapt to impacts that are already inevitable, and reduce greenhouse gas emissions, to perhaps half by the middle of the century. For policy makers, the message is relatively easy to digest. What remains scarce is the political will to make it a reality.
For national leaders, adaptation means better housing, more water storage, improved flood protection, shifts in agriculture and higher food prices, more preventative health. Not such a big issue for us rich people – but a real problem for poor countries and poor people everywhere, who ironically contribute least to climate change. And adaptation cannot save species under climate threat, or natural icons like the Barrier Reef.
Reducing emissions is the really tough thing. Not that it’s impossible or even prohibitively expensive, though you wouldn’t know it if political debate in Australia was your only source of information on the matter. Technologies to curb CO2 and other greenhouse gases exist, along with ample opportunities to save energy. The cost of cutting global greenhouse gas emissions is estimated in the order of 1% or 2% of GDP – compared to underlying GDP growth of easily 200% or more by 2050.
The trouble is lack of cooperation between nations. One country acting alone makes little difference, everyone has an incentive to free-ride, and there is little consensus on equity. India argues that its per capita emissions are ten times lower than in rich countries, China demands headroom to build up its economy the carbon intensive way the industrialised world has, and rich countries point out that most emissions growth these days comes from the poorer cousins.
A growing sense of urgency could help on the rocky road toward a new climate treaty, with negotiations due to start in Bali in December. But it is difficult to see a quick turnaround in global greenhouse emissions. Emissions growth has accelerated in recent years, exceeding even the most pessimistic scenarios developed in the late 1990s. If there’s one thing to take from this report, it’s that we’re in for a lot worse before (hopefully) things gets better.