Politicians, media, and environmentalists all over America are pointing to the record-breaking heat wave in America’s northwest and Canada’s southwest as proof of human-induced global warming. Unfortunately, localized weather and global climate aren’t the same. (The affected region, very roughly 1.5 million square miles, is under 1 percent of Earth’s total surface.) One cannot infer the latter from the former. As Science and Environmental Policy Project President Ken Haapala wrote in last week’s The Week that Was:
As mentioned in last week’s TWTW, the heatwave in the US Northwest and Canada’s Southwest came primarily from a high-pressure dome that settled over the area. The system was “stalled” by a north-south flow of the jet stream guided by Rossby Waves. Rossby Waves are planetary waves naturally occurring in rotating fluids such as the Earth’s oceans and atmosphere. First identified by Carl-Gustaf Rossby in 1939, in the atmosphere these waves can stall the normal flow of weather systems over a particular area of the earth’s land surface. In the summer, they are linked with a number of extreme “heatwaves” over Europe, Asia, and North America.
Unfortunately, many in the media, including climate scientists, claimed this localized extreme heatwave was “proof” of carbon dioxide-caused global warming / climate change. It is not. A significant part of central United States, the breadbasket of the country, was cooler than normal. Further, part of the Southern Hemisphere has been colder than normal.
Roy Spencer reports that for June 2021, global lower atmosphere temperatures were slightly below the thirty-year average. These are the most comprehensive temperature trends existing, independently verified by weather balloon data taken with different instruments. They refute the claims that the extreme heat is the result of global warming. Spencer wrote:
The Version 6.0 global average lower tropospheric temperature (LT) anomaly for June 2021 was -0.01 deg. C, down from the May 2021 value of +0.08 deg. C. … The linear warming trend since January 1979 remains at +0.14 C/decade (+0.12 C/decade over the global-averaged oceans, and +0.18 C/decade over global-averaged land). Despite the near-normal global average temperatures, the USA Lower 48 temperature anomaly of +1.44 deg. C was the warmest in the 43-year satellite record, ahead of +1.15 deg. C in 1988. In contrast, the Antarctic region (poleward of 60 S latitude) experienced its 2nd coldest June (-1.25 deg. C below the 30-year baseline), behind -1.34 deg. C in June 2017.