Halfway to climate change catastrophe
About 50bn tonnes of CO2 is emitted globally a year, with the average global citizen producing 7 tonnes of carbon dioxide, compared to about 10 tonnes in the UK. Scientists estimate global emissions need to come down to about 20bn tonnes a year if the world is to have a fair chance of limiting global warming to 2C. Professor Allen stressed that with so much still unknown about climate change, the findings in his research and, by extension, the IPPC report, deal in probabilities rather than certainties. However, the vast majority of scientists agree that the fundamental trends are clear.
Next week’s IPCC report is expected to make clear that scientists have never been more certain that humans are causing climate change. According to a sentence in a draft of the report, which could still change: “It is extremely likely that human influence on climate caused more than half of the observed increase in global average surface temperature from 1951 to 2010.”