How do we stay below a global temperature increase of 2°C ?
In the margin of the UN climate change summit in Cancún (Mexico), the EU presented a new scientific reference document. It shows that the pledges of the Copenhagen Accord are not satisfactory to limit global warming to 2°C.
The aim of the Copenhagen Accord is to limit global warming of the climate to maximum 2°C to prevent "dangerous anthropogenic interference" with the climate system. It called on all parties to make emission reduction pledges for 2020 to achieve the 2°C target.
The ‘Scientific perspectives after Copenhagen’ report discusses a number of important scientific and technical aspects of international efforts to achieve the 2°C target. It also assesses the pledges the different countries in Copenhagen made to reduce their total emission.
Conditions for 2°C target
A number of scientists in the EU made an assessment of the most relevant studies, including the IPCC Fourth Assessment Report (Intergovernmental Panel on Climate Change), and laid down three conditions that could ensure a likely chance of achieving the 2°C target:
- A peak in emissions is required by approximately 2015. The later the peak occurs, the steeper the decline in emissions would need to be in the subsequent decades. Feasibility may be exceeded and the costs of reduction measures will raise substantially.
- A decrease in emissions of 50-70% relative to 1990 levels is necessary by 2050. This assumes further emission reductions after 2050.
- Reductions of long-lived greenhouse gases, such as CO2 are essential. In addition, reductions of the short-lived greenhouse gases, black carbon aerosol, tropospheric ozone, and aviation-induced cloudiness could also make an important contribution.
Pledges fall short
Even the most optimistic interpretation of the current pledges shows they are not enough to ensure the 2°C target is feasible. Without additional pledges, the reduction percentages after 2020 may be unfeasible.
The achievement of these emission reductions highly depends on credible, efficient and fair policy instruments, which target as many emissions sources as possible.
Ambitious agreement required
The new reference document underlines the proof provided by the IPCC Fourth Assessment Report (Intergovernmental Panel on Climate Change): if we can limit warming to less than 2°C above pre-industrial temperatures, the risk of accelerated and irreversible changes in the climate system (and the large-scale negative consequences) are a lot smaller.
Scientific results clearly suggest that an ambitious political agreement is needed, as the time to act and to prevent a dangerous climate change, is almost over.
More information
Download the entire reference document ‘Scientific perspectives after Copenhagen’. The EU Climate Change Expert Group ‘Science’ (EGSci), which represents the member states, started the report under the Spanish EU-presidency and completed it during the Belgian presidency.
