50% emission reductions needed by 2050 to reach climate change targets, studies warn
Two new studies from the UK and Germany have shown that if worldwide industrial development continues at its present pace, it will be impossible to keep the rise in global temperature under its current target levels. The findings, published in two articles in the journal Nature, are based on new computer simulations of climate response to greenhouse gas emissions. The results of one of the studies came out of the Ensemble ('ENSEMBLE-based Predictions of Climate Changes and their Impacts') project, which was funded with EUR 15 million under the EU's Sixth Framework Programme (FP6). Current EU climate change policy aims to keep the global rise in mean surface temperatures to no more than 2°C above pre-industrial levels. However, the new studies warn that global warming targets will not be effective unless they are placed in the context of a cumulative carbon budget. Dr Myles Allen and his colleagues from the University of Oxford in the UK simulated the average global warming that would result from a given cumulative carbon emission. Their findings revealed that 1 trillion tonnes of carbon emissions (which would produce about 3.7 trillion tonnes of CO2) produce a 'most likely' warming of 2°C. 'Mother Nature doesn't care about dates,' said Dr Allen. 'To avoid dangerous climate change we will have to limit the total amount of carbon we inject into the atmosphere, not just the emission rate in any given year. Climate policy needs an exit strategy: as well as reducing carbon emissions now, we need a plan for phasing out net emissions entirely.' Dr Malte Meinshausen and his colleagues from the Potsdam Institute in Germany tackled the scenario differently by modelling global warming probabilities across a range of greenhouse gas emissions. They found that the probable global emissions between 2000 and 2050 will be about 1,400 gigatonnes of CO2. Should this occur, it would definitely mean a rise higher than the 2°C warming target by the end of the present century. Dr Meinshausen said of the figures: 'These cumulative budgets imply that substantial reductions in global emissions need to begin soon, before 2020. If we wait any longer, the required phase-out of carbon emissions will involve tremendous economic costs and technological challenges - far beyond what can be considered politically feasible today.' He further warned: 'If we continue to burn fossil fuels as we do today, we will have exhausted the carbon budget in merely 20 years, and global warming will go well beyond [the] 2-degree [target]. Only a fast switch away from fossil fuels will give us a reasonable chance to avoid considerable warming. We shouldn't forget that a 2°C global mean warming would take us far beyond the natural temperature variations that life on Earth has experienced since we humans have been around.'
Countries
Germany, United Kingdom