Connie Hedegaard, EU Commissioner for Climate Action, said: ''The report is clear: there really is no plan B for climate change. There is only plan A: collective action to reduce emissions now. And since we need first movers to set a plan into motion, we in Europe will adopt an ambitious 2030 target later this year. Now the question is: when will YOU, the big emitters, do the same? The more you wait, the more it will cost. The more you wait, the more difficult it will be.''
The report by IPCC Working Group III on mitigation of climate change, which was published yesterday, is the third of four reports that together will form the IPCC's Fifth Assessment Report.
Research since the IPCC's Fourth Assessment report in 2007 has led to a better understanding of the action needed to keep warming below 2°C, the threshold beyond which scientists believe there is a much higher risk that dangerous and possibly catastrophic changes in the global environment will occur.
Key action-oriented conclusions in the latest report include the following:
- To be effective, actions to tackle climate change require global-scale cooperation in reducing greenhouse gas emissions. Effective mitigation will not be achieved if individual agents advance their own interests independently.
- The deep cuts in greenhouse gas emissions needed to limit warming to 2°C compared to pre-industrial levels are possible. They will mean changes throughout the economy as well as challenging changes in technology, institutions and behaviour. Full decarbonisation of energy supply is needed in the long term.
- To have a greater than 66% chance of limiting warming to 2°C, global emissions must be cut substantially to between 40% and 70% below the 2010 level by the middle of this century and to near zero or below by 2100. This will entail large-scale change in energy systems, a rapid increase in energy efficiency, and a three- to four-fold increase in the share of zero/low-carbon energy supply. Other options would include bioenergy with carbon capture and storage.
- The longer we delay action, the more expensive and difficult it will be. Delaying would increase the costs, necessitate more rapid reductions in the future and result in an increased reliance on technologies to remove carbon dioxide from the atmosphere.
- The economic costs of mitigation are significant but will have only a small impact on economic growth over the course of this century. Globally, consumption is projected to grow by 1.6% to 3% per year under a business as usual scenario. It is estimated that mitigation action to limit warming to 2°C will reduce this growth by 0.06 percentage points per year, bearing in mind the limitations and uncertainties of long-term economic modelling. These estimates do not factor in the considerable co-benefits of climate mitigation for health and energy security.
- Estimated emissions in 2020 based on the voluntary emission pledges made by governments at the Cancún climate conference in 2010 are not consistent with cost-effective long-term reduction trajectories that have at least a 50% chance of limiting warming to 2°C, but they do not preclude the possibility of meeting that goal.
In terms of current trends, the report finds that:
- Despite a growing number of climate change mitigation policies, man-made greenhouse gas emissions grew more rapidly from 2000 to 2010 than in each of the previous three decades. The global economic crisis in 2007/2008 only temporarily reduced emissions.
- Total emissions from 2000 to 2010 were the highest in human history. In 2010, total GHG emissions were around 49 gigatonnes of CO2-equivalent (around 7 tonnes of CO2-equivalent for every person on the planet).
- About half of the total carbon dioxide emissions emitted between 1750 and 2010 occurred over the last 40 years.