The amount of greenhouse gases (GHGs) in the atmosphere reached record levels in 2011 confirm scientists, as the World Bank warns global temperatures could rise by a 'cataclysmic' 4°C
The latest figures from the World Meteorological Organization (WMO) reveal that atmospheric concentrations of GHGs including carbon dioxide, methane and nitrous oxide, reached new highs in 2011.
Levels of CO2 hit 390.9 parts per million (ppm), up from 389ppm in 2010 and continuing the trend of a steady increase over the last decade. Meanwhile, methane levels rose for the fifth year in a row, having previously stabilised between1999 and 2006.
According to the WMO, the increase between 1990 and 2011 in GHGs in the atmosphere resulted in a 30% rise in the effect of global warming. And, it warns that we can no longer rely on carbon sinks to continue to absorb CO2 at current rates.
"Billions of tonnes of additional carbon dioxide in our atmosphere will remain there for centuries, causing our planet to warm further and impacting on all aspects of life on earth," said WMO secretary-general Michel Jarraud. "Future emissions will only compound the situation."
"Until now, carbon sinks have absorbed nearly half of the carbon dioxide humans emitted in the atmosphere, but this will not necessarily continue in the future. We have already seen that the oceans are becoming more acidic as a result of the CO2 uptake, with potential repercussions for the underwater food chain and coral reefs."
At the same time, a new report commissioned by the World Bank warns that without tougher international targets to cut GHG emissions, temperatures are likely to rise by at least 3°C by 2100, and if countries fail to meet their current climate change commitments temperatures could rise by 4°C as early as the 2060s.
Such temperatures will, according to the 106-page report, result in devastating heat waves across vast areas of the globe, at least a 0.5m rise in sea-levels and an irreversible loss of biodiversity and ecosystems services.
The report, entitled Turn down the heat, outlines in detail the "cataclysmic" impacts that a 4°C temperature rise would have, particularly in developing economies. Predicted damage includes severe reductions in agricultural output, increasing risks of flood and droughts, and the decimation of species, such as coral reefs.
The report concludes, however, that global warming could be halted at 2°C if organisations and policymakers ramp up their efforts to cut GHGs, arguing that there are "technically and economically feasible" ways to do so.
"A 4°C warmer world can, and must be, avoided," said Jim Yong Kim, president of the World Bank. "Lack of action on climate change threatens to make the world our children inherit a completely different world than we are living in today.
"The world must tackle the problem of climate change more aggressively. Greater adaptation and mitigation efforts are essential and solutions exist. We need a global response equal to the scale of the climate problem, a response that puts us on a new path of climate smart development and shared prosperity. But time is very short."
