Marine heatwaves across the world’s oceans can displace habitat for sea turtles, whales, and other marine life by 10s to thousands of kilometers. They dramatically shift these animals' preferred temperatures in a fraction of the time that climate change is expected to do the same, new research funded by NOAA's Climate Program Office shows.
To measure that temporary dislocation of ocean surface temperatures, which can in turn drive ecological changes, NOAA scientists have now introduced a new metric called “thermal displacement.” A research paper describing the changes and the means of measuring them was published in the journal Nature this week.
Research scientist Michael Jacox of NOAA Fisheries’ Southwest Fisheries Science Center called it a powerful new way of looking at marine heatwaves.
“When the environment changes, many species move,” Jacox said. “This research helps us understand and measure the degree of change they may be responding to.”
Scientists have typically characterized marine heatwaves based on how much they increase sea surface temperatures, and for how long. Such local warming particularly affects stationary organisms such as corals. In contrast, thermal displacement measures how far mobile species must move to track ocean surface temperatures.
The extent of thermal displacement caused by marine heatwaves may not necessarily correspond to their intensity.
Thermal displacement depends on the sea surface temperature gradient, the rate at which temperature changes across the ocean. If a heatwave warms an area of ocean, fish, turtles, whales, and other species may have to travel great distances if the temperature gradient is weak, but not if the gradient is strong.
“It may give us an idea how the ecosystem may change in the future,” said Michael Alexander, research meteorologist at NOAA’s Physical Sciences Laboratory and a coauthor of the new research. The changes may have implications for coastal communities if commercial fish species shift. Fishermen would have to travel hundreds of miles farther to reach them, he said.
Sea lion mothers struggled to feed their pups as a marine heatwave known as "The Blob" shifted their most favored prey north, far from rookeries in Southern California. Photo credit: Jim Milbury/NOAA Fisheries
For example, a 2012 marine heatwave in the northwest Atlantic pushed commercial species such as squid and flounder hundreds of miles northward. At the same time it contributed to a lobster boom that led to record landings and a collapse in price.
“Given the complex political geography of the United States’ Eastern Seaboard, this event highlighted management questions introduced by marine heatwave-driven shifts across state and national lines,” the scientists wrote.
“While these management issues are often discussed in the context of climate change, they are upon us now,” the scientists wrote. “Modern day marine heatwaves can induce thermal displacements comparable to those from century-scale warming trends, and while these temperature shifts do not solely dictate species distributions, they do convey the scale of potential habitat disruption.”
A 2014-2015 Pacific marine heatwave known as “the Blob,” shifted surface temperatures more than 700 kilometers, or more than 400 miles, along the West Coast of the United States and in the Gulf of Alaska. That moved the prey of California sea lions farther from their rookeries in the Channel Islands off Southern California. This left hundreds of starving sea lion pups to strand on beaches.
Across the world’s oceans, the average long-term temperature shift associated with ocean warming has been estimated at just over 20 kilometers, about 13 miles, per decade. By comparison, marine heatwaves have displaced temperatures an average of approximately 200 kilometers, roughly 120 miles, in a matter of months. In effect, marine heatwaves are shifting ocean temperatures at similar scales to what is anticipated with climate change—but in much shorter time frames.
The research was supported by funding from the NOAA Climate Program Office’s Coastal and Ocean Climate Applications program and Modeling, Analysis, Predictions, and Projections program and the NOAA Fisheries Office of Science and Technology.
MISSION: The Climate and Fisheries Adaptation Program (CAFA) is a partnership between the Office of Oceanic and Atmospheric Research (NOAA Research) Climate Program Office, and the National Marine Fisheries Service (NOAA Fisheries) Office of Science and Technology that supports targeted research to promote adaptation and resilience of the nation's valuable fisheries and fisheries-dependent communities in a changing climate. By bringing together NOAA scientists with many partners, CAFA addresses priority needs for information and tools identified in the NOAA Fisheries Climate Science Strategy, Regional Action Plans, and other sources.
ISSUE: Healthy fisheries are a significant component of the U.S. economy. Commercial and recreational marine fisheries generate over $200 billion in economic activity and support more than 1.8 million jobs annually (FEUS 2016). Fisheries also support working waterfronts and coastal communities, provide opportunities for commerce, are tied to rich cultures, and help meet the growing demand for seafood across the U.S. and the world.
Climate change is impacting fish stocks, fisheries, and fishing communities, and these impacts are expected to increase. Changing climate and ocean conditions (e.g. warming oceans, changing currents, coastal inundation, extreme events, etc.) can affect the abundance, distribution, and productivity of fish stocks that support economically important fisheries. Sustainable fisheries management requires an improved understanding of how climate, fishing, and other stressors interact to affect fish stocks (including their habitats and prey), fisheries and fishing-dependent communities.
PROGRAM HISTORY: The CAFA Program was established by the NOAA Research Climate Program Office and the NOAA Fisheries Office of Science and Technology in 2014 to advance understanding of climate‐related impacts on fish stocks, fisheries and fishing communities. The partnership originated through the former Coastal and Ocean Climate Applications (COCA) Program and in 2021 was renamed the Climate and Fisheries Adaptation (CAFA) Program as part of the Climate Program Office Adaptation Sciences Program.
SPONSORS: Funding for the CAFA Program comes from the OAR Climate Program Office and the NMFS Office of Science and Technology, the Office of Sustainable Fisheries, and the Northeast Fisheries Science Center.
NOAA ResearchClimate Program Office
P: (301) 734-1261
Office of Science and Technology
P: (301) 427-8134
Americans’ health, security and economic wellbeing are tied to climate and weather. Every day, we see communities grappling with environmental challenges due to unusual or extreme events related to climate and weather.
NOAA Privacy Statement|
Web Accessibility Statement|
Disclaimer for External Links|
U.S. Department of Commerce|