CLIMATE scientists can be a gloomy lot, but the professional pessimism of some is in danger of seriously misleading politicians.
Ahead of the crucial UN summit in France, more than 150 countries have submitted pledges for climate-change mitigation after 2020. An assessment of these suggests that global annual emissions of greenhouse gases in 2030 will equate to between 55 and 60 billion tonnes of carbon dioxide.
This has led some climate scientists to declare that staying below the 2 掳C warming limit, and hence avoiding dangerous climate change, is impossible. But the evidence indicates that it is achievable, even without large-scale negative-emissions projects, such as bioenergy with carbon capture and storage.
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The , published by the UN Environment Programme, analysed scenarios outlined in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. It found that resulted in a 50 to 66 per cent chance of avoiding warming beyond 2 掳C, all with no need for negative emissions and assuming moderate mitigation efforts began in 2010 and are not delayed until after 2020.
These require annual emissions to drop from the current 50 to 53 billion tonnes to a median of 37 billion tonnes by 2020, 36 billion by 2030, 27 billion by 2050, and 14 billion by 2100. This is technically plausible, even if it needs more action than is planned.
Governments recognise the gap between present commitments and an emissions pathway that avoids dangerous climate change. It is likely that the Paris agreement will initiate a process through which countries will ramp up the scale of cuts, acknowledging that what is on the table now should be a floor, not a ceiling, for reductions.
快猫短视频s must shelve cynicism about the political will to tackle climate change. Instead they must help governments, the public and businesses understand what must be done to have a reasonable chance of staying below 2 掳C.
鈥溈烀ǘ淌悠祍 must shelve cynicism about the political will to tackle climate change鈥�
Otherwise there is a danger that politicians may get the mistaken impression that evidence shows this is impossible, and will stop trying to meet this crucial goal.
This article appeared in print under the headline 鈥淜eeping our cool鈥�
