(Web Desk) - Climate change could bring more lightning to forests in northern reaches of the globe, increasing the risk of wildfires, a new study shows. Researchers found that lightning is the main cause of fires similar to those seen in parts of Canada this summer.
These forests limit climate change by trapping planet-heating carbon.
More lightning could spark a vicious cycle, as trees and soil set ablaze release warming CO2 - creating more storms and potentially more lightning.
While the overall number of fires has decreased around the world over the last two decades, they have increased markedly in heavily forested areas outside the tropics.
This year Canada experienced a fire season like no other - over 6,500 fires blazed, burning around 18 million hectares (45 million acres) of forest and land.
Smoke from those fires drifted into major cities in Canada and the US, even crossing the Atlantic to Spain and Portugal.
Unlike other years which saw fires confined to the western part of the country, 2023 was marked by conflagrations across the entire territory including in eastern regions like Quebec.
The majority of these fires in northern parts were started by lightning strikes according to experts.
This new study used machine learning tools to develop a new global map showing forest fires by their ignition sources.
The authors found that 77% of burned areas in these forests are related to lightning ignitions. This is very different from tropical regions where humans are the main cause.
In the remote forests where lightning is the main fire starter, these conflagrations can rapidly turn into mega-fires.
"When a thunderstorm passes through this landscape, there are thousands of lightning strikes, and some hundreds of them start little fires," said Prof Sander Veraverbeke from the Vrije Universiteit Amsterdam, one of the authors on the research paper.
"And these can grow together into mega-fire complexes that become the size of small countries. Once these fires are so big, it becomes very difficult to do anything about them."