Category: Climate Change

Why the Ridge Keeps Coming Back: The Structural Shift Behind Western Heat Domes

~ Deirdre Des Jardins ~ Leave a comment

Part 2: The leading mode of North American winter circulation has changed, and March 2026 is what the new mode produces In Part 1, I described the diabatic engine behind March 2026's record-shattering western heat dome: upstream precipitation in the Pacific Northwest released latent heat that amplified an extraordinary ridge over the interior West. That … Continue reading Why the Ridge Keeps Coming Back: The Structural Shift Behind Western Heat Domes

The Diabatic Engine Behind March 2026’s Record-Shattering Western Heat Dome

~ Deirdre Des Jardins ~ Leave a comment

And why the same mechanism that built the 2021 Pacific Northwest heat dome is doing it again, in early spring As I write this in mid-March 2026, the western United States is in the grip of a heat wave that has no precedent in the cool-season observational record. Downtown Los Angeles hit 92°F last Thursday. … Continue reading The Diabatic Engine Behind March 2026’s Record-Shattering Western Heat Dome

Response to Jay Lund’s “Nine California Water Rites”

~ Deirdre Des Jardins ~ 2 Comments

Jay Lund published a clever satire of California water rhetoric today, and he's right that policy-based evidence-making occurs in our water debates. I worked with Jay and other Delta Independent Science Board members in 2021 to save the Delta Independent Science Board from defunding, and I value his truthtelling. But Jay's framing misses something critical … Continue reading Response to Jay Lund’s “Nine California Water Rites”

Comments to the NAS Panel on Review of the Long-Term Operations of the CVP and SWP

Observed vs modeled Tropical Pacific warming patterns
~ Deirdre Des Jardins ~ 2 Comments

Good afternoon, committee members. My name is Deirdre Des Jardins.  I’m a consultant to the Institute for Fisheries Resources and the Pacific Coast Federations of Fishermen’s Associations on climate change and modeling, as well as the Director of California Water Research. My research background is in nonlinear dynamics and complex systems theory. I did research … Continue reading Comments to the NAS Panel on Review of the Long-Term Operations of the CVP and SWP

Analysis: Proposed state investments inadequate to address increase in catastrophic flood risk

~ Deirdre Des Jardins ~ 1 Comment

The Governor Newsom's May Revise Budget provides an additional $115 million in investments in flood risk reduction, including: $75 million to support local flood control projects $40 million for the San Joaquin Floodplain restoration This is in addition to the $202 million proposed by the Governor in January to reduce flood risk in urban areas, … Continue reading Analysis: Proposed state investments inadequate to address increase in catastrophic flood risk

Water Board’s Decision 1641 adopted in wetter period

Tree in wet and dry landscape
~ Deirdre Des Jardins ~ 2 Comments

This blog post analyzes long term changes in the Sacramento Four River runoff using a 10 year and 30 year running mean. Sacramento River runoff was lower during the Dust Bowl era drought of 1928-34, and the current 30 year mean runoff is close to the mean for the historic record. However, the current 10 … Continue reading Water Board’s Decision 1641 adopted in wetter period

Climate adaptation: match crops to climate

~ Deirdre Des Jardins ~ 4 Comments

The problem is not growing water-intensive crops in California, but growing them in the driest areas in the state. The arid scrubland on the southern floor of the San Joaquin Valley gets about 7-8 inches of rain a year.

Delta tunnel — Inconvenient truths about sea level rise and salinity intrusion

Polar ice sheet melting
~ Deirdre Des Jardins ~ 2 Comments

The Delta tunnel Draft Environmental Impact Report (DEIR) has a new Sea Level Rise Study in Technical Appendix 5A-F. The study was done with Bay-Delta SCHISM, a 3-D hydrodynamic model of the San Francisco Bay and Delta. The new SCHISM study has limitations, in that it assumes that Delta levees are raised to keep up … Continue reading Delta tunnel — Inconvenient truths about sea level rise and salinity intrusion

The eye of the storm and the State Water Resources Control Board

~ Deirdre Des Jardins ~ 2 Comments

The State Water Resources Control Board’s Climate Change Mitigation Strategist, Max Gomberg, just retired, and sent an incendiary parting letter to his colleagues, stating, Witnessing the agency’s ability to tackle big challenges nearly eviscerated by this Administration has been gut wrenching. The way some of you have simply rolled over and accepted this has also … Continue reading The eye of the storm and the State Water Resources Control Board

Budget negotiations could determine the future of California’s Central Valley

~ Deirdre Des Jardins ~ Leave a comment

Modeling by the Department of Water Resources for the 2022 Central Valley Flood Protection Plan Update shows that peak flood flows on the San Joaquin River could more than double with climate change, and peak flows on the Sacramento could increase by 40%. In 2018, Daniel Swain, Baird Langenbrunner, and David Neelin found that there … Continue reading Budget negotiations could determine the future of California’s Central Valley