Where is climate change being felt most acutely?
CLIMATE CATASTROPHES have come thick and fast in recent months. In June an unprecedented heatwave blasted the Pacific northwest, creating the conditions for devastating wildfires. In July extreme floods in central China killed more than 30 people. In August deadly fires have been blazing across Turkey and Greece. Against this backdrop the Intergovernmental Panel on Climate Change (IPCC)the UN-backed body that assesses scientific opinion on the issuereleased its latest report on Monday. Published eight years after its predecessor, it is the most comprehensive recent examination of the physical science on climate change. One of the most remarkable things about the report is the volume of concrete evidence. When the IPCC compiled its last big report in 2013, it referred to just three studies linking extreme weather events to rising temperatures. For the latest report the experts were able to assess hundreds of such event-attribution studies. The expansion of observational information in the past eight years almost amounts to a new scientific discipline, and allows empirical evidence to be incorporated into research alongside theories and models. This strengthens the understanding of the fundamental processes, and thus should improve predictions made for the years ahead. It also shows how the world is already being remade. Of the 45 regions into which the IPCC divides the world (represented in the chart by hexagons), 41 have suffered from more cases of extremely high temperatures since the 1950s. In two areas, central and eastern North America, there was no overwhelming signal and the scientists could not agree on quite what was going on. In two others (the southern cone of South America and central Africa) the evidence wasnt reliable or extensive enough to support any firm conclusion. For more than half of the regions that warmed, scientists now have high confidence that humans contributed to the warmingthat is, that it would not have occurred without greenhouse gases being pumped into the atmosphere, largely by burning fossil fuels. The report concludes, for the first time, that it is unequivocal that human influence has warmed the atmosphere, ocean and land. That is a marked progression from the IPCCs second report, published in 1995, which only tentatively opined that the balance of evidence suggests a discernible human influence on global climate. Many parts of the world have also experienced much more heavy precipitation (particularly in central and eastern North America and most of Europe and Asia, as well as southern Africa); more droughts have been observed elsewhere. Although the impact of human activity is not as clear-cut as with high temperatures, human influence has probably made compound eventssuch as heatwaves seen in conjunction with droughts, or flooding caused by both rain and sea-level risemore common. The IPCCs findings should have several consequences. Government representatives from 195 countries signed on to them, making it harder for decision-makers to ignore. The stark data on the effects of climate change should be an alarm call for rich countries to help poor ones to better adapt to the heating planet. Everyone must do more to mitigate against further warming. And the reports firm conclusion that human activity has already changed the planet reinforces the idea that humans can help to shape its future. The UN climate summit being held in Glasgow this November has its agenda.