Wildfire is reshaping the forests of California's Sierra Nevada and affecting the water those forests supply to downstream users.
A paper published in Hydrology and Earth System Science reports that the effect of wildfire on potential runoff from the state's main water-supply watersheds has increased in the period 1985-2023, most markedly since 2019.
It's time to think bigger about mitigating climate change.
Measures such as recycling, turning off lights and reducing energy use are great, but making a real impact is going to take systemic change, said Leah Stokes, a political scientist, energy expert and climate communicator from UC Santa Barbara.
Temperatures in the 90s are nothing new to the northern San Joaquin Valley. But having them in March, as expected this week, is unusual and potentially dangerous.
An exceptionally strong ridge of high pressure will bring record-breaking heat to the entire region, the National Weather Service said. Temperatures in the San Joaquin Valley are likely to reach 90 degrees by Tuesday and 95 by Friday. That's 20 to 25 degrees above normal.
High-risk conditions for fires are increasingly happening across countries at the same time, making wildfires even more challenging to tackle, new research reveals.
Scientists from UC Merced and the University of East Anglia found this synchronized extreme fire weather — characterized by exceptionally warm, dry and often windy conditions — has increased strongly worldwide since 1979, becoming more widespread throughout regions, not just in single locations.
One of the biggest hurdles facing local farmers is the rising cost of doing business.
However, some innovative solutions are in the works, as highlighted at the Central Valley Rural Energy Systems Workshop at UC Merced in early December.
The global climate crisis was entirely predictable and impacts nearly every facet of life. But we still can slow its progress and mitigate the effects we already see.
That was the message delivered earlier this month by climate scientist Michael Mann, who spoke at the first in a series of presentations at UC Merced planned for the university community and the public.
Mann said he and colleagues published research in the 1990s that showed the Earth's warming and the impact of the Industrial Revolution on the climate.
Wildfires are growing more frequent and severe across the western United States, and California's Sierra Nevada is ground zero. Decades of fire suppression have left these forests overstocked and vulnerable to catastrophic fires, drought and pest outbreaks.
Beyond destroying homes and infrastructure, high-severity wildfires release massive amounts of carbon, degrade water quality, erode soils, reduce timber supply and fill the air with hazardous smoke that threatens public health.
Lightning from thunderstorms rolling through Central California on Sept. 2 ignited numerous wildfires, including several large fires in the Sierra Nevada foothills that had burned more than 19 square miles by Wednesday morning. The California Governor’s Office of Emergency Services recorded more than 9,000 lightning strikes in a single day.
Lightning is a major source of wildfire ignition in the western United States every summer.
Recently, more than 150 students at 10 high schools in Los Angeles, New York City and Washington, D.C. completed Climate Justice, a UC Merced course , through a unique partnership between the University of California and the National Education Equity Lab.
Pictures accompanying Professor John Abatzoglou's presentation on the 2025 fire season were blurry. That was intentional, he said, because so much about wildfire is unpredictable.
"There's a lot that we know, and a lot we don't know," he said.
