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Tuesday, July 02, 2019

Will Forest Fires be our nemesis ?

In southern California, December is meant to bring the start of rainy season. Not in 2017. The Thomas fire, the worst of those that roiled the region that year, grew 50,000 acres in one day, eventually burning 440 sq miles and forcing the evacuations of more than 100,000 Californians. A week after it was sparked, it remained, in the ominous semi-clinical language of wildfires, merely “15% contained”.

Five of the 20 worst fires in California history hit the state in the autumn of 2017, a year in which more than 9,000 separate fires broke out, burning through almost 1.25 m acres – nearly 2,000 sq miles made soot. 

In the summer of 2018, the fires were fewer in number, totalling only 6,000. But just one, made up of a whole network of fires, together called the Mendocino Complex, burned almost half a million acres alone. 

In total, nearly 3,000 sq miles in California turned to flame, and smoke blanketed almost half the country. 

Things were worse to the north, in British Columbia, where more than 3 m acres burned, producing smoke that would travel across the Atlantic to Europe

Then, in November, came the Woolsey Fire, which forced the evacuation of 170,000, and the Camp Fire, which was somehow worse, burning through more than 200 square miles and incinerating an entire town so quickly that the evacuees, 50,000 of them, found themselves sprinting past exploding cars, their sneakers melting to the asphalt as they ran. It was the deadliest fire in Californian history.

When trees die – by natural processes, by fire, at the hands of humans – they release into the atmosphere the carbon stored within them, sometimes for as long as centuries. In this way, they are like coal. This is why the effect of wildfires on emissions is among the most feared climate feedback loops – that the world’s forests, which have typically been carbon sinks, would become carbon sources, unleashing all that stored gas. 

The impact can be especially dramatic when the fires ravage forests arising out of peat. Peatland fires in Indonesia in 1997, for instance, released up to 2.6gigatons (Gt) of carbon – 40% of the average annual global emissions level. 

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