The endangered Hawksbill turtle in the Atlantic Ocean, off the Florida coast. Photo: Mark Conlin/VW Pics/UIG via Getty Images

EU - Climate change drives record North Atlantic marine heat wave

The historic heat waves that roasted the U.S. and Europe over the summer may have subsided. But a record marine heat wave is gripping large expanses of the North Atlantic and northern Pacific oceans.

The big picture: It has implications for marine species and extreme weather events, including hurricanes, as climate change exacerbates the problem. NOAA scientists warn it shows no signs of immediately abating.

Driving the news: "Climate change is making every marine heatwave warmer than the last," research scientist Dillon Amaya, who studies marine heat waves at NOAA's Physical Sciences Laboratory, tells Axios.

  • "Climate change increases the mean temperature of the ocean (i.e., global warming)," Amaya says. "Marine heatwaves ride that upward trend and are becoming warmer as a result."

By the numbers: "The North Atlantic is currently something like four degrees Celsius warmer than normal, or at least parts of it are. And you end up seeing similar numbers for the North Pacific as well, it's for about four degrees Celsius warmer than normal," Amaya says.

State of play: Heat wave conditions in both the North Pacific and the North Atlantic have lasted for some three months. "For these parts of the world, these temperatures are unprecedented," Amaya says.

  • Vincent Saba, a fishery biologist at NOAA's Northeast Fisheries Science Center, notes it's "warmed faster in the U.S. Northeast shelf than any other region across the country in the last 15 years."
  • Fish biomass was still relatively stable, but scientists had observed changes in marine species in the Northwest Atlantic, Saba said in a phone interview last week.
  • In the Pacific Ocean, there's a La Niña climate event for the third year in a row. This can lead to warmer than normal conditions in the Northeast Pacific, Amaya said.

Of note: Warming isn't the only impact of climate change.

  • "We're also talking about an increased concentration of carbon dioxide in the water, which makes the waters more acidic," Saba says.
  • "That can impact shelf species like lobster, highly valuable sea scallops. We're still unclear on what those impacts are."

Threat level: "With climate change some marine species will fair better than others," Saba says.

  • Research suggests warmer water species are staying in the U.S. Northeast for longer, while North Atlantic right whales are foraging in different waters as they follow their planktonprey, which have moved locations — raising concerns about ship collisions and entanglement with fishing gear.
  • It's unclear whether this is due to climate change or warming waters, per Saba.
  • "We've seen major changes in species distributions," he says. "Warmer water species moving north, and a lot of colder water species moving further north out of the system has kind of been the general trend."
  • Research that Saba and his colleagues have conducted found warmer waters were leading to almost all female sea turtles hatching — though projections indicate the biggest long-term threats will be in hatchling mortality as nests and beaches warm up and erosion from sea level rise destroys nests.

Zoom in: Bette Zirkelbach, manager of the Turtle Hospital in the Florida Keys, said along with the hatchlings issue, she's seen an increased prevalence of fibropapillomatosis (FP), a tumor-causing disease that primarily affects green sea turtles.

Read more.