Quantcast

How Climate Change Ignites Wildfires From California to South Africa

Climate
A wildfire near Santa Barbara, California. John Newman / U.S. Forest Service

The link between climate change and more frequent, severe wildfires is well-known, but two new studies published in Geophysical Research Letters this month provided more insight into exactly how warming temperatures are increasing fire risk around the world.

In fire-weary California, urbanization and global warming are increasing ground temperature along the southern coast, decreasing cloud cover and increasing the risk of wildfires.


Meanwhile, in the Mediterranean and temperate parts of the Southern Hemisphere, it's what comes out of the clouds that causes the problems: Lightning-ignited fires are on the rise and likely to keep rising with global temperatures.

The California study was published May 24 and reported by Columbia University in Phys.org Wednesday.

"Cloud cover is plummeting in southern coastal California," study co-author and Columbia University bioclimatologist Park Williams said. "And as clouds decrease, that increases the chance of bigger and more intense fires."

The researchers found low-lying summer clouds in the Los Angeles area had decreased by 25 to 50 percent since the 1970s. The decrease in cloud cover was mostly driven by urbanization, which increases the temperature of the ground, but overall global warming also contributed. Warmer ground drives away clouds, which leads the direct sunlight to heat the ground further, drying out vegetation and increasing the chance that it catches fire.

The study found that the total area burned by fires in Southern California had not increased, mostly because urbanization had also decreased the amount of burnable land and because firefighting techniques had improved.

"Even though the danger has increased, people in these areas are very good at putting out fires, so the area burned hasn't gone up," Williams said. "But the dice are now loaded, and in areas where clouds have decreased, the fires should be getting more intense and harder to contain. At some point, we'll see if people can continue to keep up."

Williams said that reduced cloud cover was likely not behind 2017's devastating fires, which were caused by wind, a dry fall and a surfeit of burnable vegetation that had grown in the record rains following California's record drought.

The lightning study was published May 15 and reported by Portland State University Thursday in Phys.org.

The study looked at the relationship between the frequency of lightning-started fires, warming temperatures overall and the impact of three regular climate-altering phenomenons: El Niño-La Niña, the Indian Ocean Dipole and the Southern Annular Mode.

The study found that warming temperatures increased the frequency of fires, and also increased the influence of all three climate phenomena on fires in the warmer early 21st century compared to the end of the 20th.

"We think that by having warmer oceans and warmer temperatures in general, we're going to see higher evaporation and heat transfer, and thus higher frequency of convective storms that in turn results in more lightning-ignited fires," study co-lead author and Portland State University geography professor Andrés Holz said.

Fires especially increased due to the activity of the Southern Annular Mode (SAM), the north-south movement of westerly winds that circle Antarctica and bring moisture to the southwest tip of continents in the Southern Hemisphere. This is because during the "positive phase" of SAM, when the westerly winds retreat to Antarctica, global warming and the hole in the ozone layer have combined with the climate driver to increase heat and decrease precipitation in Australia, South Africa and southern South America.

Worldwide, Holz said that, unless global rainfall patterns changed, global warming was likely to increase fires in wet regions that had previously been too humid for fires, but would decrease fires in historically dry regions.

EcoWatch Daily Newsletter

Wesley Martinez Da Costa / EyeEm / Getty Images

By David R. Montgomery

Would it sound too good to be true if I was to say that there was a simple, profitable and underused agricultural method to help feed everybody, cool the planet, and revitalize rural America? I used to think so, until I started visiting farmers who are restoring fertility to their land, stashing a lot of carbon in their soil, and returning healthy profitability to family farms. Now I've come to see how restoring soil health would prove as good for farmers and rural economies as it would for the environment.

Read More Show Less
skaman306 / Moment / Getty Images

By Jillian Kubala, MS, RD

Radish (Raphanus sativus) is a cruciferous vegetable that originated in Asia and Europe (1Trusted Source).

Read More Show Less
Sponsored
Tinnakorn Jorruang / iStock / Getty Images

By Dan Nosowitz

The budding research on cannabidiol, or CBD, attracts a great deal of interest in the agricultural field.

Read More Show Less
Oksana Khodakovskaia / iStock / Getty Images

By Jillian Kubala, MS, RD

The loquat (Eriobotrya japonica) is a tree native to China that's prized for its sweet, citrus-like fruit.

Read More Show Less

The Centers for Disease Control (CDC) released new numbers that show vaping-related lung illnesses are continuing to grow across the country, as the number of fatalities has climbed to 33 and hospitalizations have reached 1,479 cases, according to a CDC update.

Read More Show Less
Sponsored
During the summer, the Arctic tundra is usually a thriving habitat for mammals such as the Arctic fox. Education Images / Universal Images Group via Getty Images

Reports of extreme snowfall in the Arctic might seem encouraging, given that the region is rapidly warming due to human-driven climate change. According to a new study, however, the snow could actually pose a major threat to the normal reproductive cycles of Arctic wildlife.

Read More Show Less
Vegan rice and garbanzo beans meals. Ella Olsson / Pexels

By Alina Petre, MS, RD (CA)

One common concern about vegan diets is whether they provide your body with all the vitamins and minerals it needs.

Many claim that a whole-food, plant-based diet easily meets all the daily nutrient requirements.

Read More Show Less
A fracking well looms over a residential area of Liberty, Colorado on Aug. 19. WildEarth Guardians / Flickr

A new multiyear study found that people living or working within 2,000 feet, or nearly half a mile, of a hydraulic fracturing (fracking) drill site may be at a heightened risk of exposure to benzene and other toxic chemicals, according to research released Thursday by the Colorado Department of Public Health and Environment (CDPHE)

Read More Show Less