The entire northern hemisphere across parts of the western contiguous U.S., Europe, north-central Russia and southeastern China had its hottest summer on record this year, the World Meteorological Organization (WMO) said.
The heat is contributing to a record-breaking destructive 2020 fire season on the west coast during the warmest August on record, it confirmed citing the US National Oceanic and Atmospheric Administration (NOAA).
The WMO’s global dissemination of NOAA findings comes just a day after President Donald Trump dismissed hotter climate as a cause of the fierce blazes raging across California, Oregon and Washington state. Joe Biden called Trump a “climate arsonist”.
WMO is a discreet agency that sticks studiously to its science-based technical knitting. But it has global reach with a membership of 193 governments and provides leadership for raising public awareness about climate issues.
Trump’s recent suggestions in Sacramento that hotter climate may not underlie the worsening wildfires year after year have raised eyebrows in the international community.
He thinks poor forest management is the main cause of raging fires. Fallen trees become very dry after about 18 months and act like matchsticks. “They just explode,” Trump said.
While this is true, meteorological experts also underline the role of rising heat because of climate change. This is indicated by the ferocity and frequency of wildfires.
Entire neighborhoods have been razed to the ground along the west coast, causing dozens of casualties and forcing the evacuation of thousands of people. Air quality has worsened for millions and turned skies orange. Clouds of smoke have billowed over the western Pacific and traveled more than 1,300 miles, as seen by satellites.
The latest US Fourth National Climate Assessment finds that climate change led to twice as much land being burned from 1984 to 2015, than if climate change had not occurred. This season, wildfires burned about 2,510,743 acres in the United States with California at the top of the unfortunate list.
Climate change has also led to more intense droughts, which combined with increased temperatures have desiccated forests, turning them into tinder. Strong winds feeding off the heat and low humidity fan the flames.
Wildfires can start with a lightning strike or human activity. The US National Interagency Fire Center estimates that 36,383 fires were caused by humans, out of 41,599 fires so far this year.
Such figures give some credence to Trump’s argument about better forest management but do not explain the high temperatures and drought conditions that feed the ferocity of multiple wildfires raging at the same time.
Drought conditions increased by 7 percent in August and covered 40% of the US. Worse, more than 14,000 lightning strikes occurred along the west coast between August 15-31.
Evidence for the negative effects of climate change on forest fires is mounting. This year saw six of the top 20 largest wildfires in California history, according to Cal Fire. Seven of the top ten most destructive wildfires have occurred since 2015 and eight of the top ten occurred in the last ten years.
The Northern Hemisphere had its warmest June-August period on record at 1.17°C above average, surpassing the second warmest such period in 2016 and again in 2019. The five warmest June-August periods for the Northern Hemisphere have occurred since 2015.
At global level, August was the second warmest on record, at 0.94°C above the 20th-century average of 5.6°C. It was also the 44th consecutive August and the 428th consecutive month with temperatures nominally above the 20th-century average.
The 10 warmest Augusts have occurred since 1998 and the five warmest Augusts have occurred since 2015. Those years also saw worsening wildfires, hurricanes and other adverse climate change impacts.
Wildfires are not a bad thing but too many can permanently alter the ecosystem. Otherwise, they are part of the natural cycle of life. As a fire blazes, it heralds fresh forest growth by killing pests and germinating new seedlings.