Fire. One degree above global average temperature increases area burned by 222%, study says – Executive Digest

California in the United States saw an average of 361 km² burned per year between 1971 and 1995. Since 1996, the area burned annually has increased fivefold to 1,710 km² per year. Climate change has played an essential role in this increase: according to a study published in the scientific journal PNAS, each degree on the thermometer increases the area burned.

Almost everywhere on the planet, the rate of evaporation, or desiccation — the amount of moisture soil loses — is increasing, and scientists have taken measurements in northern California and the Sierra Nevada. Scientific work has linked the number of hectares burned between 1971 and 2021 to a series of factors: some climate or weather, such as temperature or precipitation. Others are environmental or astronomical, such as emissions from volcanic eruptions or radiation variations due to the solar cycle. But the creation of greenhouse gases is included in the equation.

“Anthropogenic emissions are known, so remove them from the simulations to find out what the natural evolution looks like,” said Marco Turco, an Italian researcher at the University of Murcia and co-author of the work published in ‘PNAS.’ he said. According to the study, nearly 98% of the variation in burned areas can be attributed to climate factors. Since 1971, the average temperature has risen by 0.8º and the burned area has increased nearly fivefold each year.

“The fire-time relationship is exponential and we found a 222% increase in burned area with a one-degree increase in maximum monthly temperature,” he added.

According to the results of the study, if the temperature continues to rise, the burned area will continue to grow: “The model, to say the most promising, gives a 40% increase in the burned area relative to the current climate. At two degrees this increase will be 60% and at three degrees it will be 97%”, said the expert.

“The same factors that support wildfires in California’s forests apply to many other countries with Mediterranean climates,” said John Apatzoglob, head of the University of California’s Climatic Laboratory and co-author of the paper.