Monday , January 25 2021

Ten ways of climate change can exacerbate fires

PARIS: Deadly fires like those who roar in northern and southern California have become more common throughout the state and elsewhere in the world in recent years. The AFP has talked to scientists about how climatic changes can get worse.

Other factors also stimulated increased incidence and intensity of large-scale fires, including human burnout in forest areas and questionable forest management. "The patient was already sick," says David Bowman, a professor of environmental biology at the University of Tasmania and a fire expert.

"But climate change is accelerating."

Every firefighter can tell you a recipe for a "fire fire": hot, dry, and windy.

It is not surprising, therefore, that many tropical and moderate regions have been destroyed by the impact of forest fires envisaged in climatic models to see more temperatures and more droughts.

"In addition to bringing more dry and hot air, climate change – by increasing the rate of evaporation and precipitation of droughts – creates more flammable ecosystems," said Christopher Williams, Environmental Science Director at Clark University, Massachusetts.

In the last twenty years, California and southern Europe have seen a few droughts that have only happened for a century.

Dry weather means more dead trees, shrubs and grasses – and more fuel for fire.

"All of these extreme dry years create a huge amount of dried biomass," said Michel Vennetier, engineer of the French National Science and Technology Research Center for Environment and Agriculture (IRSTEA).

"It's an ideal fuel."

To make things worse, new types better tailored to semi-dry conditions grow in their place.

"Plants that love moisture have disappeared, replaced by more flammable plants that can withstand dry conditions, such as rosemary, wild lavender and thyme," Vennetier said.

"Change is happening very quickly."

With rising alive and fewer rainfall, trees and shrubs under water point deeper into the ground, drawing every drop of water that can feed leaves and needles.

This means that the humidity on Earth that has helped slow the fire that blows the forest or the garrison is no longer there.

In the temperate zone of the northern hemisphere, the fire season was historically short – July and August, in most places.

"Today the period subject to fires is extended from June to October," said IRSTEA Thomas Curt, referring to the Mediterranean swimming pool.

In California, which has just emerged from a five-year drought, some experts say there is no season at all – fires can occur throughout the year.

"The worse it is, the more lightning," said Mike Flannigan, a professor at the University of Alberta, Canada, and the director of the Western Partnership for Wildland Fire Science.

"Especially in the northern areas, it means more fire."

At the same time, he pointed out that 95 percent of world fires begin with people.

Normal time patterns across North America and Eurasia depend heavily on high-altitude air currents at high altitudes – resulting in contrast between polar and equatorial temperatures – known as the jet stream.

But global warming on the Arctic has raised temperatures twice as fast as the global average, weakening the current.

"We see more extreme weather conditions because of what we call blocked ridges, which is the high pressure system in which the air melts, gets warmer and gets dry on the road," Flannigan said.

"Firefighters have known for decades that it contributes to the activities of the fire."

Climate change not only increases the likelihood of fire but also their intensity.

"If the fire becomes too intense," as in California, and last year in Greece "there is no direct action you can take to stop it," Flannigan said.

"It's like spitting on a campfire."

With rising temperatures, the turtles moved north to the Canadian boreal forests, causing desolation and killing of trees – on the road.

"The turtle epidemic provokes a temporary increase in forest fire by increasing the amount of dead material, such as needles," Williams said.

Globally, forests account for about 45 percent of Earth's carbon and absorb a quarter of greenhouse gas emissions from the country.

But as the forests die and burn, part of the carbon is released back into the atmosphere, contributing to climate change in the vicious loop that scientists call "positive feedback".

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