Commitments made after Copenhagen are far from sufficient to keep global warming below 2°C. Without further measures 3°C is more likely, and 5°C a possible scenario.
The Copenhagen climate summit last December failed to reach a binding agreement for the period after 2012, when the Kyoto protocol expires. To avoid complete failure, 114 states came up with a non-binding agreement, the Copenhagen Accord, on the very last night of the meeting. Another ten countries have signed later.
The Copenhagen Accord stated an aim of keeping global warming below 2°C, and reviewing a 1.5°C goal by 2015. However, no global or national emission targets were included. Signatory states were urged to fill in national pledges for emissions reduction targets for 2020 later. By mid-April, 76 countries, accounting for about 80 per cent of global industrial emissions, had done so. A group of scientists, most of them at the Potsdam Institute for Climate Impact Research, has investigated to what extent these commitments are sufficient to meet the 2°C target. The result, recently published in Nature, is alarming.
Projected global temperature increase in a pessimistic scenario, where nations meet only their lowest stated ambitions for 2020 under the Copenhagen Accord, while using all surplus allowances and land-use credits. The blue graph shows the same scenartio, but with halved emissions (compared to 1990 levels) from 2020 to 2050.
The scientists find the national pledges made under the Copenhagen Accord amazingly meager and gives a few examples:
- The EU target of 20 per cent cuts will mean smaller annual reductions from now to 2020 than have been accomplished on average over the last 20 years.
- The United States provided a 2020 target of 17 per cent below 2005 levels, which is equal to no more than 3 per cent below 1990 levels. Canada has followed suit, which means that it is the only country effectively arguing for an increase of 2020 emission allowances above its current Kyoto protocol target: 3 per cent above instead of 6 per cent below 1990 levels.
- The less ambitious end of China’s target (reducing CO2 emissions relative to economic growth by 40–45 per cent compared to 2005 levels) merely corresponds to business-as-usual development.
Only two developed countries have made sufficient pledges under the Copenhagen Accord. Japan´s target is 25 per cent below 1990 levels, and Norway aims at 30–40 per cent.
If all nations meet the ambitious end of their targets, annual emissions from developed countries in 2020 would be 15.7 Gt CO2-eq, which is 15 per cent below 1990 levels. Recalling that the latest IPCC assessment called for a 25–40 per cent reduction, the shortcoming of the Copenhagen Accord becomes obvious.
Furthermore, due to weaknesses in the system there are reasons to consider even more pessimistic scenarios. The most significant loophole is the possibility under the Kyoto protocol for nations to sell surplus emission allowances or to “bank” them for use after 2012. Some countries with weak Kyoto target are likely to generate large amounts of surplus allowances even without further efforts to reduce emissions. In the Nature article, it is estimated that they may add up to 11 Gt CO2-eq annually. If all nations hit their lowest stated ambitions while taking full advantage of the loopholes, the annual emissions of developed countries by 2020 will be 6.5 per cent above 1990 levels. This actually exceeds business-as-usual projections.
In the worst-case scenario outlined above, total global emissions (including those from developing countries, deforestation, aviation and shipping) are estimated at 53.6 Gt CO2-eq by 2020, while the best-case scenario stops at 47.9. This means that global emissions in 2020 would be 10–20 per cent higher than today.
Based on model simulations, the scientists conclude that even the optimistic scenario – 48 Gt emissions by 2020 – is far from being on track if global warming is to be kept below 2°C. On the contrary, it would require unprecedented emission cuts after 2020. “It is equivalent to racing towards a cliff and hoping to stop just before it,” the authors state. Even if emissions are halved between 2020 and 2050, there is at best a toss-of-the coin chance of keeping warming under 2°C. The few pledges for 2050 made under the Copenhagen Accord so far rather suggest a 50 per cent chance that warming will exceed 3°C by 2100.
Roger Olsson