Ученые Калифорнии представили отчет о климатических угрозах для северо-западного побережья штата

A discussion of the North Coast Regional Report, released in October and part of California’s Fifth Climate Change Assessment, took place Thursday morning with researchers from Cal Poly Humboldt. The report covers Del Norte, Siskiyou, Humboldt, Trinity, Mendocino and Lake counties. Researchers described the region as one of the most geographically varied in the state, with low‑lying coastal plains, inland valleys and steep mountain ranges in the Klamath and Lassen areas. Cal Poly Humboldt faculty members Dr. Andrew Stubblefield and Dr. Rosemary Sherriff led the webinar. Stubblefield specializes in hydrology and watershed management; Sheriff’s background is in biogeography and forest ecology. “The community advisory board represented individuals from all of the counties, and their lived experiences contributed to the scope of the report, as well as the technical advisory board giving input all the way along, including reviewing final drafts,” said Sherriff. “We emphasize the need for collaborative approaches, and that traditional ecological knowledges or place-based knowledges built on observation, ceremony, and adaptive practices that not only enhance biodiversity but really have proven and shown climate resiliency.” Heat, drought and shifting seasons Temperatures across the region have climbed steadily over the past century, with sharper increases in the past two decades. Summers are projected to warm more quickly than winters, driving longer fire seasons and more frequent extreme heat events. “One of the things that really stands out about our region is the rural and remote nature. There’s unique challenges with respect to our climate impacts that might be different from a more central urban part of California, but also gives us real strengths and opportunities that we can play to,” said Stubblefield. “In our region, climate change impacts grow worse. Hotter, drier summers leading to wildfires and drought, intense rainfall and flooding, loss of forests and species, sea level rise, coastal erosion, and kelp bed die-offs.” Stubblefield said summers are projected to warm more quickly than winters, with more days over 100 degrees and longer heat waves. Seasonal rainfall patterns are also shifting. Winters are expected to bring heavier downpours, increasing the risk of flooding and landslides. Fall and spring will dry out, lengthening the fire season and raising drought risk. “Looking at rainfall, we see what’s been called seasonal sharpening. We’re getting an increase in precipitation during the winter months when we’re already seeing a lot of rainfall and flooding. So that will make flooding worse. And associated with that is landslides. Intense rainfall is often what triggers landslides, blocking roads and inundating houses,” said Stubblefield. “The other aspect of the seasonal sharpening is less rain in the fall and spring, and so what that means is a longer dry season … more chance of drought and worse wildfires.” Sinking coastline meets rising ocean Humboldt Bay’s North Spit is experiencing the fastest sea level rise rate in California. “The North Spit here in Humboldt has the highest sea level rise rates in California,” said Stubblefield. “We’ve already observed a foot of sea level rise.” Unlike Crescent City and Arena Cove, where geologic uplift offsets some sea-level rise, Humboldt Bay is sinking at the same rate as sea-level rise. Subduction beneath the region causes the land surface to drop as water levels rise, amplifying the apparent rate of change. One example is already visible. A freshwater marsh on Elk River Spit that sat 375 feet inland in 2018 had retreated to roughly 30 feet by 2023. “It’s now part of the bay. (It’s a) really dramatic warning of the type of changes that the rest of California will be seeing in coming decades as the shoreline responds to the higher sea level,” said Stubblefield. Researchers said shoreline retreat should be expected and planned for. They recommended expanding salt marshes, restoring coastal buffers and using nature‑based shoreline protection to absorb wave energy.” Rivers, lakes and aquatic resilience Higher air temperatures and longer dry seasons will warm rivers and lakes, reduce dissolved oxygen and stress aquatic species. Lower flows will intensify stratification in lakes, limiting oxygen circulation to deeper waters. “For rivers and lakes, we’ll see hotter temperatures leading to hotter water temperatures. We’ll see less water inputs because of the climatic water deficit to lower flows,” said Stubblefield. “Those low flows will reduce dissolved oxygen levels, placing stress on aquatic organisms and higher water temperatures from lower flows.” He outlined several water‑focused strategies, including protecting shaded headwater streams, expanding estuarine habitat for juvenile salmon, reducing diversions in small tributaries, creating off‑channel refuges during floods, restoring beavers to increase natural water storage, and managing dams to release cold water or remove barriers entirely. Erosion, kelp loss and marine habitat Coastal ecosystems face kelp bed die‑offs, erosion and habitat shifts driven by warming waters and rising seas. “We can protect our shaded headwater streams and larger spring-fed streams to help keep that water cool. We can create off-channel habitat where fish can have velocity refugia and can escape the high floodwaters,” said Stubblefield. “We can bring back beavers and increase streamside vegetation across the watersheds. We can manage our dams to release more cold water or remove dams to allow fish to access the mountains and the higher cold water refugia” Researchers described nature‑based coastal tools such as building berms to create salt marshes, breaching dikes to reclaim tidelands, reducing development‑driven habitat loss, buffering agricultural and urban runoff and supporting fisheries transitions and marine protected areas. “We can reduce other stressors such as habitat loss to development,” Stubblefield said. Tribal stewardship and cultural burning Forests across the North Coast face timber loss, tree mortality, habitat decline, invasive species, and pathogen spread. Drought and heat amplify these risks. The region’s vast landscapes are rich in biodiversity, endemic species, and carbon storage and serve as “ecological insurance.” “We have biodiversity and endemic species, productive and diverse ecosystems, and a lot of carbon being sequestered,” said Stubblefield. “We provide a model for adaptive management efforts; the Klamath Dam removal has gained international attention. We have sustainable livestock production, collaborative management, cultural burning, and Indigenous stewardship.” Rural infrastructure strained The North Coast’s infrastructure is highly vulnerable. The region relies on single‑corridor highways, single‑source power lines, and water systems without backups. “Our built infrastructure systems face really large cascading risks across the six counties that make up the North Coast region. Representing about 19,000 square miles,” said Sherriff. “This is larger than nine of our 50 states and around the size of West Virginia, but in our region we have single highway corridors, single-source power lines, and water systems commonly without secondary supplies. So this leads us to being susceptible, and we have seen cascading and compounding failures.” The report recommends reclassifying microgrids and local water partnerships as essential infrastructure to unlock public funding. Insurance frameworks, they said, should recognize climate‑resilient retrofits and nature‑based risk reduction. “We’ve seen in the North Coast and other areas successful examples of nature-based and integrated approaches, and so we need to expand the eligibility of those types of approaches throughout the North Coast region,” said Sherriff. “For example, furthering cultural burning that’s occurring in cultural landscape management using bio-engineered slopes, which is cheaper and less to maintain than constructed slopes and constructed wetlands, that for example increase important habitat but also help us deal with rising sea level rise.” Structural inequities A map presented during the webinar showed nearly the entire North Coast qualifies as disadvantaged under state screening tools. “Our region is very underserved in terms of resources, and another important component is that rural and tribal conditions, such as the North Coast region, differ from urban frameworks,” said Sherriff. “We have small governments, small staffing, low funding, and state programs often require matching funds that rural places such as the North Coast don’t have.” The report cites legacies of colonization, extractive economies, high poverty rates, limited staffing, and small local governments as barriers to adaptation. Sherriff emphasized strong tribal leadership, land return efforts, Indigenous‑led restoration, and expanding traditional ecological knowledge programs at Cal Poly Humboldt. “We have incredibly strong tribal leadership. Our tribes are leaders on all of these issues that we’re talking about. We have very important land return that’s occurred. That’s a model for other areas of the state and the nation,” said Sherriff. Region positioned to lead Researchers closed by noting that the North Coast’s landscapes, tribal stewardship, and restoration expertise position the region to lead statewide adaptation if funding, permitting, and insurance frameworks evolve to support rural communities. “For our region, we need to plan for cascading and compounding impacts. We need to protect climate refugia, aquatic and terrestrial, and as we plan for adaptation, we need to think of restoration and conservation as ecological insurance,” said Stubblefield. “The North Coast is historically under-resourced, but has strong community networks and tribal knowledge. Nature-based solutions provide multiple benefits as well as adaptation to impacts, and with funding, the North Coast can be a leader in climate adaptation.” Maranda Vargas can be reached at (707) 441-0504