Concentrations of greenhouse gases in our atmosphere, driven by man-made carbon emissions, reached a record high in 2011, according to the World Meteorological Organisation (WMO).Carbon dioxide levels rose to 390.9 parts per million (ppm) in 2011, a 40% increase on levels in 1750. Other greenhouse gases such as methane and nitrous oxide also reached record levels. Michel Jarrud, secretary-general of the WMO warned that billions of tonnes of additional carbon dioxide would remain in the atmosphere for centuries: "…causing our planet to warm further and impacting on all aspects of life on earth."
While nearly half of the carbon dioxide emitted by humans has been absorbed by natural carbon sinks such as our oceans, this may not be the case for future emissions.
"We have already seen that the oceans are becoming more acidic as a result of the carbon dioxide uptake, with potential repercussions for the underwater food chain and coral reefs. There are many additional interactions between greenhouse gases, Earth’s biosphere and oceans, and we need to boost our monitoring capability and scientific knowledge in order to better understand these," says Jarraud.
Understanding the role of carbon sinks is key to understanding how increasing levels of greenhouse gases in our atmosphere will contribute to rising global temperatures.
The bulletin by WMO follows another report released by the World Bank on Sunday, warning that the world is on track for a 4oC rise in temperatures this century - bringing with it extreme heat waves and a life-threatening sea level rise.
"A 4oC warmer world can, and must be, avoided – we need to hold warming below 2oC," says World Bank group president Jim Yong Kim.
"Lack of action on climate change threatens to make the world our children inherit a completely different world than we are living in today. Climate change is one of the single biggest challenges facing development, and we need to assume the moral responsibility to take action on behalf of future generations, especially the poorest."