A new report from the U.N.’s Intergovernmental Panel on Climate Change predicts that future warming will accelerate the frequency and intensity of heat extremes — such as heat waves and heat waves that can’t be explained by natural variability.
“At high confidence, the range of projected temperature increases for the global mean during the 21st century is greater than 4 degrees Celsius [7.2 degrees Fahrenheit],” the IPCC’s Special Report on the Climate Change 2014 Science Edition says. “This is equivalent to the warming of the last century. It is highly likely, at around 45 per cent, that they exceed this threshold.”
The Intergovernmental Panel on Climate Change was established by the United Nations General Assembly in 1988 to provide scientists with a consensus on the issue of climate change. This is the panel’s 26th assessment of the science in 20 years, as the scope of climate change has become increasingly complex.
But the new report, released Wednesday, isn’t the first dire scientific warning that extreme heat is on the horizon.
A 2017 report from the National Climate Assessment cited more than 200 scientific studies that found that extreme heat would be another hazard requiring the same level of adaptation — or more — as climate change itself.
In most regions of the country, the combination of extreme heat, increased precipitation, and atmospheric moisture will worsen existing health risks to heat-sensitive populations, the report said. It is now clear, the report said, that the heat will begin showing up in a more severe and widespread way around the world as early as summer 2019.
Over the past century, the study found, people in the United States have already adapted to harmful effects of heat such as heat stroke, dehydration, and heat exhaustion, because of improvements in air conditioning, public health and education. But the commission expects that adaptation will be undermined by a rapid increase in extreme heat in coming decades.
The report is one of the most ambitious efforts to date by any body to forecast the physical effects of climate change on Earth. It reviews the changing climate from all different angles and adds some fresh analysis, such as climatologists’ expectation that much of the future warming will be driven by ocean heat.