How to avoid critical levels of climate change?

The Conference of the Parties to the UN Framework Convention on Climate Change will hopefully have this month adopted the 2°C target from the Copenhagen Accord in a legal text. After many years of negotiation, a target has finally been formulated which the world believes needs to be met to avoid dangerous climate change and fulfil the objective of the Convention. This is a very big step forward!

But the year's climate science suggests that dangerous anthropogenic interference with the climate system cannot be ruled out at 1.5°C, and that various tipping points initiating severe damage may be triggered with between 0.5°C and 2°C of global warming. Examples are sea level rises threatening the existence of small island states; damage to communities and agricultural production in many countries; and threats to the survival of several global ecosystems due to climate change.

Today more than 100 countries support a 1.5°C target, and it must also be agreed to as a goal of the Climate Convention. Various scientific institutions, governments and NGOs are researching and developing new strategies on how to reach this goal. According to this research, climate policies in the next one to four years will be very important if the 1.5 or 2°C target is to be reached.

The research suggests that global greenhouse gas (GHG) emissions must peak in coming years and at the latest by 2015, and be reduced drastically thereafter at rates of at least three per cent annually, if the world is to have a chance of reaching the 2°C goal. During 2010, global GHG emissions increased by three per cent.

What probability of success or chance of failure should the world accept when setting policies designed to reach these targets? The EU's latest scientific climate report (see article) is based on a 66 per cent probability of reaching the 2°C degrees target. This is an unacceptable large risk, given that it threatens any possibility of reaching a 1.5°C target. Instead, a probability of success of more than 90 per cent should be applied, given the high costs of failure.

Cumulative emissions of GHGs are the most important factor, and long-lived carbon dioxide (CO2) emissions are responsible for 80 per cent of the greenhouse effect. Scientists have calculated what the remaining CO2 emissions budget is which would allow temperatures to stay below 2 degrees. The results are frightening and show a very large gap between the commitments presented in the Copenhagen Accord and the reductions needed. Annually, the world is currently emitting around 30 gigatonnes (Gt) of CO2 (2008 figures). The remaining budget of CO2 emissions, if we are to have more than 90 per cent chance of reaching the 2°C target, is around 600 Gt of CO2. This amount of CO2 will be used up by the world in 20 years if the present level of emissions continues, and much faster if annual emissions continue to increase.

To address this very large gap between the necessary targets and present commitments, the science calls for much more immediate action to be taken by the world's governments. They should immediately develop a global emergency action programme for drastic reductions of all greenhouse gases over the next 20 to 30 years, and an assistance programme for developing countries of several hundred billion euros annually.

This action programme should be developed by agreeing to principles of fair allocation of the available carbon space and an appropriate effort sharing formula. The time for these decisions is many years overdue, and must now be taken at the last minute before the window to reach a 1. 5 or 2°C target is closed!

Reinhold Pape

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