It has been an alarming time for climate scientists. One by one, the grim scenarios they had outlined for the near future have been overtaken by events: extreme storms, droughts, floods and ice-sheet collapseswhose sudden appearances have outstripped researchers’ worst predictions. Catastrophic climate change is happening more rapidly and with greater intensity than their grimmest warnings, it transpires.
Examples include this summer’s record high temperature of 40.3C in the UK, a massive jump of 1.6C on the previous hottest day; torrential rains that triggered the most severe flooding in Pakistan’s recent history; and last year’s Hurricane Ida, one of the most destructive storms to have struck the US.
It is not that global temperatures have risen faster than expected. The problem is that the effect of this rise has been unexpectedly extreme.
“Many of the impacts of climate change such as increased weather extremes are now playing out faster than predicted, even though the warming itself is very much in line with model projections,” said the American climatologist Michael E Mann, of Pennsylvania University.
This point was backed by Johan Rockström, director of the Potsdam Institute for Climate Impact Research in Germany.
“Without doubt, extreme weather events, amplified by global warming, are coming faster than predicted and are more severe than predicted. The impacts are there to see: the disastrous floods in Pakistan; the failure of the rainy season in Somalia for the past four years; and highly destructive wildfires in California,” he said.
These unanticipated events are occurring in a world that is currently 1.2C hotter than it was in pre-industrial times and temperatures are likely to continue to rise considerably despite nations pledging at recent IPCC summits to do everything to hold increases to 1.5C.
This figure could be breached in a decade, say scientists. The result will be even worse droughts, heatwaves, floods and disease patterns than those now being experienced.
But that is not all, says Rockström. He and his colleagues have recently published research that indicates that by the time a global temperature rise of 1.5C is reached there would be a significant risk to four major systems. “These systems include the Greenland ice sheet and the West Antarctic ice sheet, which will start to disintegrate,” added Rockström. “The end result will be sea level rises of several metres though that could take many, many decades.”
In addition, the permafrost systems of Canada and Russia would start to thaw and release their vast stores of methane, a greenhouse gas many times more potent and dangerous than carbon dioxide. Finally, at temperature rises of about 1.5C, all of the planet’s tropical coral reef systems would start to collapse, the group found.It would mean that we would be handing over to our children and to all future generations, a planet that will be sliding irreversibly towards possessing fewer and fewer places to live,” Rockström said.