2-degree warming unstoppable

The country climate action plans submitted in advance of the upcoming UN climate change talks in Paris are not enough to limit temperature rise to 2 degrees Celsius by 2100, finds the UN in a new report.

Published on Friday, the report assesses the collective impact of over 140 national climate action plans, known as Intended Nationally Determined Contributions or INDCs. The INDCs will form the basis of the agreement that many hope will be reached at COP21 in Paris starting at the end of November.

According to a UN news release on the launch of the report, this “unprecedented worldwide effort” to combat climate changes builds “confidence that nations can cost effectively meet their stated objective of keeping global temperature rise to under 2 degrees Celsius” by making a significant dent in the growth of greenhouse gas emissions.

However, a closer look at the figures in the UN report shows that those efforts are simply not enough to limit global warming to 2 degrees. Even if all countries implement their INDCs, it will still result in a forecast temperature rise of around 2.7 degrees Celsius by 2100 – something that even Christiana Figueres, UNFCC Executive Secretary, admits is “by no means enough”.

An article in the New Scientist digs deeper into UN report and states that according to the UN’s own analysis, the world will have emitted enough carbon dioxide by around 2036 to warm the planet by 2 degrees Celsius:

“It has been calculated that to have a 66 per cent chance of limiting warming to 2 °C, cumulative emissions from 2011 must be limited to 1000 GtCO2. The UN report, however, says we’ll have burned through 75 per cent of this carbon budget by 2030. That means we could only emit another 250 GtCO2 after 2030 – which means we’ll bust the budget in around 2036 assuming emissions stay above 40 GtCO2 per year.”

As that article explains, the 2-degree limit is based on the assumption that the world will resort to geo-engineering to remove vast quantities of CO2 from the atmosphere. But many scientists remain extremely sceptical that geo-engineering on such a scale is even feasible, let alone safe.

It is far more likely that full implementation of the INDCs could limit temperature rise to between 2.7 and 3.5 degrees Celsius by 2100, but that depends on what countries do beyond 2030 – a period not covered by the INDCs.

 

Photo credit: UN Photo/Evan Schneider

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