Fires ignited by lightning have and will likely continue to increase across the Mediterranean and temperate regions in the Southern Hemisphere under a warmer climate, according to a new study co-led by a Portland State University researcher.
The study, published online in May in the journal Geophysical Research Letters, examined the observed and forecasted relationship between lightning-ignited fires, rising temperatures across the Southern Hemisphere and natural climate variability in three leading climate drivers that affect weather worldwide: El Niño-La Niña, the Indian Ocean Dipole and the Southern Annular Mode.
El Niño-La Niña, known as ENSO, is the periodic warming and cooling periods of the equatorial eastern and central Pacific Ocean that affects the world’s climate the most. The Indian Ocean Dipole, or IOD, is a similar ocean-atmospheric phenomenon characterized by changes in sea-surface temperatures between the eastern and western part of the Indian Ocean, while the Southern Annular Mode, or SAM, describes the north-south movement of the westerly wind belt that circles Antarctica and carries moisture to the southwest corners of all the Southern Hemisphere continents.
Heat, oxygen, fuel and an ignition source combine to start wildfires, but where and how quickly a fire moves depends on the terrain, the types and condition of vegetation present and the weather, said Andrés Holz, the study's co-lead author and a geography professor in PSU's College of Liberal Arts and Sciences.
Read more at Portland State University