Guest essay by Eric Worrall
When record breaking cold occurs it is just weather, but according to Slate, climate attribution, the science of retrofitting explanations to unusual weather events after they happened, can demonstrate that a single unusual heatwave is evidence of climate change.
The First Undeniable Climate Change Deaths
In 2018 in Japan, more than 1,000 people died during an unprecedented heat wave. In 2019, scientists proved it would have been impossible without global warming.
By DANIEL MERINO JULY 23, 20205:45 AM
uly 23, 2018, was a day unlike any seen before in Japan. It was the peak of a weekslong heat wave that smashed previous temperature records across the historically temperate nation. The heat started on July 9, on farms and in cities that only days earlier were fighting deadly rains, mudslides, and floods. As the waters receded, temperatures climbed. By July 15, 200 of the 927 weather stations in Japan recorded temperatures of 35 degrees Celsius, about 95 degrees Fahrenheit, or higher. Food and electricity prices hit multiyear highs as the power grid and water resources were pushed to their limits. Tens of thousands of people were hospitalized due to heat exhaustion and heatstroke. On Monday, July 23, the heat wave reached its zenith. The large Tokyo suburb of Kumagaya was the epicenter, and around 3 p.m., the Kumagaya Meteorological Observatory measured a temperature of 41.1 degrees Celsius, or 106 F. It was the hottest temperature ever recorded in Japan, but the record was more than a statistic. It was a tragedy: Over the course of those few weeks, more than a thousand people died from heat-related illnesses.
On July 24, the day after the peak of the heat wave, the Japan Meteorological Agency declared it a natural disaster. A disaster it was. But a natural one? Not so much.
In early 2019, researchers at the Japan Meteorological Agency started looking into the circumstances that had caused the unprecedented, deadly heat wave. They wanted to consider it through a relatively new lens—through the young branch of meteorology called attribution science, which allows researchers to directly measure the impact of climate change on individual extreme weather events. Attribution science, at its most basic, calculates how likely an extreme weather event is in today’s climate-changed world and compares that with how likely a similar event would be in a world without anthropogenic warming. Any difference between those two probabilities can be attributed to climate change.
…Read more: https://slate.com/technology/2020/07/climate-change-deaths-japan-2018-heat-wave.html
The Slate article quotes Yukiko Imada of the Japan Meteorological Agency. The abstract of Yukiko Imada’s study;
The July 2018 High Temperature Event in Japan Could Not Have Happened without Human-Induced Global Warming
The high temperature event in July 2018 caused record-breaking human damage throughout Japan. Large-ensemble historical simulations with a high-resolution atmospheric general circulation model showed that the occurrence rate of this event under the condition of external forcings in July 2018 was approximately 20%. This high probability was a result of the high-pressure systems both in the upper and lower troposphere in July 2018. The event attribution approach based on the large-ensemble simulations with and without human-induced climate change indicated the following: (1) The event would never have happened without anthropogenic global warming. (2) The strength of the two-tiered high-pressure systems was also at an extreme level and at least doubled the level of event probability, which was independent of global warming. Moreover, a set of the large-ensemble dynamically downscaled outputs revealed that the mean annual occurrence of extremely hot days in Japan will be expected to increase by 1.8 times under a global warming level of 2°C above pre-industrial levels.Read more: https://www.jstage.jst.go.jp/article/sola/15A/0/15A_15A-002/_article/-char/ja/
Climate attribution science would be a little more believable if it could predict unusual events in advance, say give a year or two warning that Japan was about to suffer an extreme heatwave. Providing explanations of events which have already happened does not demonstrate skill.