Wildfires affect soil and release more carbon and toxics, study finds

A recent study reveals wildfires alter soil composition, leading to increased carbon dioxide and toxic release.

Sharon Udasin reports for The Hill.


In short:

  • The study highlights how black carbon from wildfires does not sequester carbon dioxide as effectively as hoped, speeding up its conversion back to CO2.
  • Research shows wildfires double the soil levels of harmful polycyclic aromatic hydrocarbons, obstructing plant regrowth.
  • Findings suggest wildfires convert metals into toxic forms, contaminating water supplies and hindering ecological recovery.

Key quote:

"Carbon that’s gone through forest fires and becomes black carbon can actually turn more readily into carbon dioxide by microbes than previously thought."

— Scott Fendorf, professor, Stanford University’s Doerr School of Sustainability

Why this matters:

When wildfires rage through an area, the intense heat incinerates vegetation and organic matter that are crucial for healthy soil. This loss not only depletes the soil of nutrients but also reduces its ability to store carbon, leading to increased levels of carbon dioxide—a greenhouse gas that contributes to global warming—released back into the atmosphere. In addition, the structure of the soil changes, becoming more compact and less able to absorb water. This leads to greater runoff during rainfalls and can also cause harmful substances like heavy metals to be more easily washed into rivers and streams, affecting water quality and aquatic life.

Two images showing the same mountain range, one with adequate snow and one with less snow

As glaciers shrink, Central Asian states find way to share water

Five Central Asian nations once bickered over the water from regional glaciers. Now, with climate change looming, they appear set to share use.
a mountain range with light snow and a desert environment in the foreground

Warm temperatures hamper snowpack formation in Nevada

Snowpack in Nevada and the Eastern Sierra – a major source of water for the Truckee River in northern Nevada – are below normal at 74% of median for the time of year.

A pump jack with a maintenance worker on a platform next to it

‘Wrong side of history’: Report ties top polluters to countries blocking fossil fuel phaseout

Many state-owned fossil fuel firms that emitted the highest levels of pollution in 2024 went on to block a phaseout roadmap at COP30.
A row of oil drilling pump jacks against a sunset

US energy secretary calls for doubling global oil output in Davos

The world needs to more than double oil production, U.S. Energy Secretary Chris Wright said at Davos, while criticising the European Union and the state of California for wasting money on what he described as inefficient green energy.

an empty office with a desk and a book shelf

What happened after Trump cut funding to environmental justice and community groups

Across the country, communities that lost grants have responded in a variety of ways — suing the government, searching for other funds, or simply moving on.

A man wearing a hard hat standing in front of solar panels

The consequences of Trump's war on climate in 7 charts

Seven snapshots reveal how climate rollbacks altered the trajectory of U.S. energy, environmental protection, and economic security.
China renewable energy, wind and solar energy concept. Chinese flag superimposed with wind turbines and solar panels
Credit: Anton_Medvedev/ Big Stock Photo ID: 431444246

Economic interests drive Chinese climate leadership amid U.S. retreat

As the United States retreats from climate policy, China signaled its rising intent to lead a transition away from fossil fuels and toward Chinese-made renewable energy technologies in remarks to world leaders on Tuesday.

From our Newsroom
Multiple Houston-area oil and gas facilities that have violated pollution laws are seeking permit renewals

Multiple Houston-area oil and gas facilities that have violated pollution laws are seeking permit renewals

One facility has emitted cancer-causing chemicals into waterways at levels up to 520% higher than legal limits.

Regulators are underestimating health impacts from air pollution: Study

Regulators are underestimating health impacts from air pollution: Study

"The reality is, we are not exposed to one chemical at a time.”

Pennsylvania governor Josh Shapiro speaks with the state flag and American flag behind him.

Two years into his term, has Gov. Shapiro kept his promises to regulate Pennsylvania’s fracking industry?

A new report assesses the administration’s progress and makes new recommendations

silhouette of people holding hands by a lake at sunset

An open letter from EPA staff to the American public

“We cannot stand by and allow this to happen. We need to hold this administration accountable.”

wildfire retardants being sprayed by plane

New evidence links heavy metal pollution with wildfire retardants

“The chemical black box” that blankets wildfire-impacted areas is increasingly under scrutiny.

Stay informed: sign up for The Daily Climate newsletter
Top news on climate impacts, solutions, politics, drivers. Delivered to your inbox week days.