The frequency of large wildfires has doubled over the past 20 years Forests

The frequency and size of large wildfires may have doubled over the past two decades, and these extreme weather events have intensified since 2017. These are the main conclusions of a study published Monday in the scientific journal Nature ecology and evolution.

“I was expecting to see some growth, but this rate of increase bothered me. Effects of… Climate change They were nothing from the future. “We are now seeing the emergence of a dry, hot climate,” first author Callum Cunningham, a researcher at the University of Tasmania, in Australia, tells PÚBLICO.

Scientists used 21 years of satellite data to not only identify active fires, but also calculate the overall intensity of these extreme events on the planet. Callum Cunningham acknowledges that in the light of climate science, about two decades of data is “not a very long time”, but states that this makes “the extremes doubling results even more important”.

The scientist says that the MODIS satellites of the North American Space Agency (NASA) pass over our heads four times a day, and monitor fires over the entire surface of the Earth. These devices have been operating since the beginning of this century and provide scientists with a tool to assess how fire changes the planet’s surface.

“It is important to highlight that satellites measure the energy released by fires. Instead of looking at all fires the same way, we looked at how active extreme events (those that release huge amounts of energy and cause serious damage to ecosystems, communities and the environment) are climate) changed in frequency and intensity. “These are undoubtedly the most important fires to focus on,” says Callum Cunningham.

Pedrojao tragedy in 2017

Portugal represents in this long inventory various fires in green areas, including the tragedy of Pedrogao Grande, in June 2017. Portugal has recorded several unusually intense fires in recent years. The Mediterranean climate region, in general, was one of the main foci of these severe fires. e-mail.

The study shows that the Arctic (a region that includes North America and Greenland) and Australasia (Australia, New Guinea, New Zealand and some islands in Indonesia) were the regions most affected by extreme events. The increase in these same events was primarily driven by heavy fires in coniferous and boreal forests, in both North America and Russia.

As average temperatures on Earth rise, landscapes tend to become drier, and therefore more flammable. For this reason, the climate crisis is leading to an increase not only in the frequency of large wildfires, but also in the severity of large wildfires. There have always been fires in green areas, but these phenomena now occur more violently and regularly.

Severe forest fires are associated with severe environmental, social and economic consequences, including the emission of large amounts of smoke and gases. Global Warming Which threatens to further accelerate global warming [da Terra]”, is reading study The nature of the environment and evolution.

“The scientific literature has shown for some time that climate is increasing fires and this trend is expected to increase. By focusing on extremes (rather than averages), this new work is important because it reveals what this change in fire climate looks like.” It shows that Climate change is not a distant phenomenon,” explains the first author of PÚBLICO.

What can we do?

Knowing that severe fires are on the rise, what can we do? Callum Cunningham It states that we must respond with a “multifaceted approach,” that is, fighting simultaneously on several fronts. On the one hand, we cannot fail to significantly reduce carbon dioxide emissions Greenhouse gasesOn the other hand, we have to invest in adaptation strategies. One of them involves, for example, mitigating fires through forest fuel management techniques.

“For example, Australian indigenous people managed ecosystems for thousands of years through the frequent use of cold fire, which may have prevented large catastrophic fires,” explains Calum Cunningham. A cold fire consists of a type of low-intensity burning, generally lit deliberately on a mild day.

Without the systematic use of these and other strategies, the consequences can be devastating. The study says that during Australia’s so-called Black Summer in 2019 and 2020, when fires released unusual amounts of smoke and emissions, nearly 2.8 billion vertebrates died. These extreme events also destroyed the geographical area previously occupied by 116 native plant species.