杏吧原创

Climate downgrade: Human emissions

If we stopped emitting CO2 tomorrow, we might be able to avoid climate disaster. In fact we are still increasing emissions

Building more coal or gas-fired power stations puts us on the road to decades of continued emissions
Building more coal or gas-fired power stations puts us on the road to decades of continued emissions
(Image: C. Friedrichs/Flickr/Getty)
No let up
No let up

Read more:Climate change: It鈥檚 even worse than we thought

If we stopped pumping more CO2 into the atmosphere now, we鈥檇 have a very good chance of avoiding a big hike in temperature. But there is no sign of that happening. Annual emissions fell only slightly after 2008 鈥 the biggest financial crisis since the Great Depression 鈥 and are now climbing more rapidly than ever (see diagram). So far they are . 鈥淥ur emissions are not slowing,鈥 says Paul Valdes of the University of Bristol, UK. 鈥淭hat鈥檚 the most scary aspect of our future.鈥

The only international agreement to limit greenhouse-gas emissions, the Kyoto protocol, excluded developing countries and involved only minor cuts. The US never signed up and Canada has withdrawn. Hopes for a more effective and inclusive agreement have faded.

Meanwhile China, now the world鈥檚 biggest CO2 emitter, is investing heavily in renewable energy, but its rapid growth means its emissions will still soar. Some smaller countries have unilaterally promised big cuts, but few are investing to deliver them. On the contrary, most continue to subsidise fossil fuels and to build coal or gas-fired power stations, committing themselves to decades of continued emissions. The move away from nuclear power after the meltdowns at Fukushima has made matters worse: even Germany, which was leading the way on expansion of renewable energy, is now planning to build more coal-fired power plants. 鈥淲e are going to do virtually nothing,鈥 says of the Tyndall Centre for Climate Change Research in Manchester, UK. 鈥淓very year, it looks worse than previously.鈥

So we are on a path that the 2007 IPCC report concluded would most probably lead to a 4聽掳C rise in temperature by 2100 鈥 way above the 2聽掳C level it was declared we should avoid at all costs. But this worst-case scenario was not simulated with the most advanced models when the 2007 report was being prepared, because of limited time and computing power. , and the 鈥渂est estimates鈥 are now between 5聽掳C and 6聽掳C by 2100, with roughly a 10 per cent chance of a rise of 7聽掳C. This means many of us are likely to live long enough to experience severe global warming. We are on track for , or the 2060s if carbon feedbacks (see 鈥Climate downgrade: Planetary feedbacks鈥) are high. Far from being alarmist, says Anderson, most scientists have underplayed the significance of the emissions story to make their message politically more acceptable.

鈥淢any of us are likely to live long enough to experience severe global warming鈥

Topics: Climate change / Energy and fuels