The chances of keeping the global temperature increase below 2C will “swiftly diminish” unless the world takes immediate action to escalate cuts in carbon emissions, the United Nations has warned.
The UN Environment Program said that even if nations meet their current emissions reduction pledges, carbon emissions in 2020 will be eight to 12 gigatonnes above the level required to avoid a costly nosedive in greenhouse gas output.
The Emissions Gap Report 2013, which was compiled by 44 scientific groups in 17 countries, warns that if the greenhouse “gap” isn’t “closed or significantly narrowed” by 2020, the pathway to limiting the global temperature rise to 1.5C will be closed.
At UN talks in 2010, the international community agreed to limit the rise in average global temperatures to 2C by 2100, based on pre-industrial levels.
Scientists at the recent IPCC gathering warned that the world could emit enough carbon to surpass the 2C limit within 30 years, and this latest UN analysis heightens concerns that the world could be heading for a temperature rise of 4C or even 6C, triggering damaging sea level rises, extreme weather events and food insecurity.
The Emissions Gap Report, released ahead of the UN climate talks in Warsaw, found that although the 2C target could be achieved with higher emissions by 2020, failure to significantly reduce CO2 levels will “exacerbate mitigation challenges” after this time.
“This will mean much higher rates of global emission reductions in the medium term; greater lock-in of carbon-intensive infrastructure; greater dependence on often unproven technologies in the medium term; greater costs of mitigation in the medium and long term; and greater risks of failing to meet the 2C target,” the UN Environment Program stated.
In order to avoid this scenario, the report recommends that emissions should reach a maximum of 44 gigatonnes of CO2 by 2020, falling to 40 gigatonnes by 2025 and further to 22 gigatonnes by 2050.
However, given that the 2C target was set based on the assumption that action would start in 2010, the report warns it will become “increasingly difficult” to meet this goal. Global greenhouse gas emissions for 2010, the latest year for which data is available, stood at 50.1 gigatonnes.
Although the report states the window for action is “narrowing”, the 2C target could still be achieved by implementing ambitious emissions reduction promises, tightening the rules of existing pledges and international co-operation on areas such as energy efficiency, renewables and fossil fuel subsidies.