Dangerous 3-6°C temperature rise likely by 2100
With greenhouse-gas (GHG) emissions reaching record levels, global temperatures will rise at least 3°C by the end of the century unless dramatic changes are made to policy and behavior, warn researchers
A series of independent research reports concluded that if global GHG emissions continue to follow current trends the world will be 3-6°C warmer by 2100.
A study carried out for the World Bank, concluded that temperatures could rise by 4°C as early as the 2060s if governments fail to meet existing commitments to cut GHGs, and that without tougher targets a 3°C increase is to be expected by 2100.
Such increases in temperatures will, according to the World Bank, result in devastating heat waves across, at least a 0.5m rise in sea-levels and an irreversible loss of biodiversity and ecosystems services.
Meanwhile PwC concluded in its fourth low-carbon economy index that temperature rises would be even higher. “Even doubling our current annual rates of decarbonisation globally every year to 2050, would still lead to a 6°C increase, making governments’ ambitions to limit warming to 2°C appear highly unrealistic,” said Jonathan Grant, director, sustainability and climate change at PwC.
Initial data from the Global Carbon Project on 2012 emissions, estimate at that output of CO2 around the world grew by 2.6%, despite cuts from Europe and the US, to levels that are 58% higher than in 1990. And the latest figures from the World Meteorological Organisation (WMO) confirm that atmospheric concentrations of GHGs including carbon dioxide, methane and nitrous oxide, were 30% higher in 2011 than in 1990.
“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 said WMO secretary-general Michel Jarraud. “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.”
Jarruad’s warning came as the European Environment Agency (EEA) published a report confirming that the impacts of climate change were already being felt across the bloc, with 2002–2011 revealed to be the warmest decade on record. European land temperatures were 1.3°C warmer than the pre-industrial average, reveals the EEA, and could be 2.5–4°C warmer than 1990 levels by the end of the century.
The agency’s report also confirms that over the last decade heat waves have increased in frequency and length, causing tens of thousands of deaths; incidences of both drought and floods have occurred; and that the melting of the Greenland ice sheet has doubled since the 1990s.
Melting icecaps in Greenland and the Arctic are thought to be the main cause of rising sea levels, according to the Intergovernmental Panel on Climate Change (IPCC). The IPCC’s latest research has revealed that over the last 20 years the oceans have risen by 3.2mm – 60% above existing estimates.
“Climate change is a reality around the world, and the extent and speed of change is becoming ever more evident,” commented Jacqueline McGlade, EEA executive director. “This means that every part of the economy needs to adapt as well as reduce emissions.”
Corinne Le Quéré, director of the Tyndall centre for climate change research and a professor at University of East Anglia, said: “If carbon emissions continue the way they are, they are leading to climate change of 4°C or above.
“These are really, really big changes in the way the world operates. It is very difficult to say what such a world would look like and impossible to guarantee that it would be safe for population of seven billion people.”