More lightning, more wildfires and a warmer world. Welcome to the ‘doom loop’

Climate-induced lightning is becoming more frequent and powerful, triggering more wildfires, particularly in Siberia, Canada and Alaska, and releasing the carbon locked in permafrost
Hong Kong seems likely to escape the worst of it but any complacency would be rash

David Dodwell

Published: 7:30pm, 17 Nov 2023

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As Hong Kong’s typhoon season subsides and northeasterly typhoon winds gather strength at the start of our dry season, thoughts are turning from typhoon threats to wildfires.

Research released ahead of the COP28 UN climate summit in Dubai reflects rising concern over how a global surge in climate-induced lightning is set to aggravate wildfires and compound our problems in controlling global warming and curbing forest loss.

Using artificial intelligence to map wildfires, a research team led by Thomas Janssen from the University of Amsterdam found that even though wildfires have declined globally since 2001 (partly because of better control of human-started fires across Africa’s savannahs), there has been a sharp increase outside the tropics.

The wildfire increase is concentrated in the boreal forests of Siberia, Canada and Alaska encircling the Arctic – and is set to unleash the huge volumes of carbon locked in the Arctic permafrost for centuries. By 2030, wildfires are likely to increase by 14 per cent, according to the UN Environmental Programme (UNEP).

While most of these boreal forests are out of sight and mind for many people, they account for around 30 per cent of the world’s forests. They are underlain mostly by permafrost – and the trees and permafrost they are rooted in store between 30 and 40 per cent of all terrestrial carbon.

These findings coincide with research earlier this year that identified a lightning-wildfire “doom loop” – where rising global temperatures cause stronger storms, triggering more, and more powerful, “Promethean bolts” of lightning that are strikingly effective in sparking serious and sustained wildfires. Every 1 degree Celsius of warming could cause a 10 per cent increase in Promethian bolts.

These “hot lightning” bolts – scientifically described as “long continuing current lightning” and which can last for longer than 40 milliseconds each – are very good fire-starters. They could have caused up to 90 per cent of the 5,600 US wildfires analysed.

This comes as the wildfire threat in the US is set to attract mounting concern. A congressional joint economic committee said that wildfires fuelled by climate change cost the US economy between US$394 billion and US$893 billion a year – not just because of fire damage, but also because of lower property values, smoke damage affecting people’s health, income losses, and damage to regional watersheds – land that channels rainfall and snowmelt to creeks, streams and rivers.

For instance, California’s 20 most-destructive wildfires have destroyed 40,000 homes, businesses and pieces of infrastructure, according to UNEP.

In Australia, the concern is not just about fire damage but also for the impact on wildlife. The 2020 bush fires in southeast Australia wiped out an estimated 3 billion animals, including over 60,000 koala bears.

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The growing body of research has stirred rising concern at UNEP, whose report last year, “Spreading like Wildfire: The Rising Threat of Extraordinary Landscape Fires”, was already calling for a “fire ready formula” to reassign resources, shifting priorities away from firefighting to the prevention of wildfires.

As droughts, higher air temperatures, lower humidity, more frequent and powerful lightning, and stronger winds lead to hotter, drier and longer fire seasons, the “trends towards more dangerous fire-weather conditions are likely to increase”, said UNEP in another report called “Frontiers 2022: Noise, Blazes and Mismatches”.

Wildfires have been common natural phenomena for centuries, particularly in Africa’s savannahs. Humans have also augmented them throughout history as they sought to clear land for farming, and today account for most fires across Africa and in the tropics. Between 2003 and 2016, Africa’s savannahs accounted for 77 per cent of the 13 million fires recorded, averaging 423 million hectares burned globally every year.

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But it is the new patterns of wildfire generation, most of them far beyond the sight or influence of humans, that are the most recent cause of concern. Between 2002 and 2020, only 1.2 per cent of the global burned area was outside the tropics – yet this accounted for about 8.5 per cent of all carbon emissions from fires, according to the Dutch research.

Almost all such fires are caused by lightning, not humans. Across Siberia’s boreal forests (also known as “taiga”), a series of blazes in 2003 alone accounted for 22 million hectares of scorched land; across Russia, almost 56 million hectares have been consumed by wildfires since 2001, according to Global Forest Watch.

“Future increases in lightning ignitions threaten to destabilise vast carbon stores in extratropical forests, particularly as weather conditions become warmer, drier and overall more fire-prone in these regions,” said Dr Matthew Jones, one of the researchers on the team.

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The team predicts that the biggest increases in wildfire risk are concentrated in the western United States, southeast Australia, eastern Siberia and western Canada.

Europe will be particularly vulnerable around the Mediterranean, as has been clearly seen through the past summer’s wildfire season, among its worst.

Mercifully, Hong Kong seems likely to be spared the most acute wildfire threats, perhaps because our long rainy season keeps our forests moist for most of the year. But we would be rash to be complacent. Since 2001, we have lost 118 hectares of forest cover due to wildfire. In 2018 alone, our worst wildfire year, we lost 47 hectares. Few will have forgotten the horrendous Pat Sin Leng fire in 1996, which killed five and injured many more. With our dry season about to start, we will need to stay on our guard.

David Dodwell is CEO of the trade policy and international relations consultancy Strategic Access, focused on developments and challenges facing the Asia-Pacific over the past four decades