The combination of the northern hemisphere summer, a developing El Niño, and rising greenhouse gases made July the hottest month since records began. That’s no surprise, but the size of the jump has disturbed climate scientists.
It will take a little while for all the data to be verified, but a preliminary estimate by the European Union’s Copernicus Climate Change Service estimates global average temperatures for the month will be 0.32°C (0.58°F) hotter than the previous record month, June 2019. That may not sound like much, but the record it broke was set by just 0.04°C (0.07°F) over July 2016, which is much more the sort of increment we usually see. There’s never been a jump like this since global records began.
The figures quoted here come from the European Centre for Medium-Range Weather Forecasts (ECMWF) and don’t include the last week of the month. Other instruments and analyses produce slightly different numbers, but all agree that July was far beyond anything we have seen before. Nor are there any signs the end of July changed the overall picture.
“Record-breaking temperatures are part of the trend of drastic increases in global temperatures. Anthropogenic emissions are ultimately the main driver of these rising temperatures,” said ECMWF’s Dr Carlo Buontempo in a statement. “July’s record is unlikely to remain isolated this year, C3S’ seasonal forecasts indicate that over land areas temperatures are likely to be well above average, exceeding the 80th percentile of climatology for the time of year”.
“The extreme weather which has affected many millions of people in July is unfortunately the harsh reality of climate change and a foretaste of the future,” agreed the World Meteorological Organization’s Secretary-General Professor Petteri Taalas. “The need to reduce greenhouse gas emissions is more urgent than ever before. Climate action is not a luxury but a must.”
Before last month, the world had not had a single day averaging more than 17° C (62.6° F) since records began. In July there were 26 according to the (also preliminary) estimate made by the Climate Reanalyzer site at the University of Maine.
A global record meant too many local and regional ones to count. Prominent examples include China’s hottest-ever maximum of 52.2°C (126°F) on July 16, a candidate for the highest midnight reading ever recorded (48.9° C, 120° F) and possibly the hottest ocean temperature measurement taken off Florida.
“We know that this global heat record would have been virtually impossible without the effect of humanity's greenhouse gas emissions,” said Dr Andrew King of the University of Melbourne.