Jan 10, 2019

Ocean heat is climbing 40% faster than thought

Expand chart
Trends in ocean heat from 4 different observational datasets, compared to the CMIP5 computer model mean, from 1955 through 2017. Data: Cheng et al. Science, 2019; Chart: Lazaro Gamio/Axios.

New, independent observations from ocean buoys and other data sources show Earth's oceans are warming at a rate that's about 40% faster than indicated in the 2013 U.N. Intergovernmental Panel on Climate Change (IPCC) report.

Why it matters: The study, published Thursday in the journal Science, resolves a key uncertainty in climate science by reconciling analyses from a variety of different scientific teams.

The oceans are absorbing about 93% of the extra heat going into the climate system. So far, most of that heat resides in the upper ocean, and is only slowly diffusing down into deeper waters. Faster warming is already resulting in tangible, harmful impacts, from coral bleaching across the Great Barrier Reef to rapidly intensifying hurricanes.

  • Scientists describe the ocean as having a "long memory," meaning that the heat going into the waters now will continue to be released long after humans cut greenhouse gas emissions (assuming we do take that course).

Be smart: The data from four different research groups now generally match the ocean heat content projections from the newest climate models, the study finds, which indicates that these models are accurately simulating the Earth's radiation budget.

  • “We can see the emergence of the signal of global warming much more clearly in ocean heat content,” says study co-author Zeke Hausfather, an energy systems analyst at the climate research group Berkeley Earth.
  • Hausfather says 2018 will be the warmest year on record for the Earth's oceans, beating the record set just last year.

How it works: Because the ocean's heat content doesn't vary as sharply as surface temperatures, it is considered a more reliable indicator of global warming.

The impact: Warmer oceans are already causing unprecedented back-to-back coral bleaching events, and are contributing to sea-level rise. They're also causing glaciers to melt from below in Greenland and Antarctica.

  • Warmer waters provide critical fuel for extreme storms, with studies showing ties between Hurricane Harvey's devastating deluge and warmer than average waters in the Gulf of Mexico, for example.

Why you'll hear about this again: The oceans are a main reason why climate change will not relent even if emissions were to cease today, since they will continue to release heat, and also greenhouse gases, over time. There are also implications for carbon removal technologies, which are getting more attention from scientists and investments from major oil companies.

Lost in much of the discussion on carbon removal, however, is the potential for the oceans to spoil the party.

“The climate system has a long memory," Hausfather says, “It doesn’t warm as quickly as it otherwise would and it’s a lot harder to cool it back down once it starts warming.”

  • The bottom line: "Just like the oceans buffer the rate of warming, they would also similarly buffer the rate of cooling in a world where we had net-negative emissions," Hausfather says.

He cited a 2016 study that showed it would take slightly more negative emissions to reduce warming than it takes positive emissions to increase temperatures.

Go deeper

Coronavirus dashboard

Illustration: Sarah Grillo/Axios

  1. Global: Total confirmed cases as of 9 p.m. ET: 857,487 — Total deaths: 42,107 — Total recoveries: 178,034.
  2. U.S.: Leads the world in confirmed cases. Total confirmed cases as of 9 p.m. ET: 188,172 — Total deaths: 3,873 — Total recoveries: 7,024.
  3. Business updates: Should you pay your rent or mortgage during the coronavirus pandemic? Find out if you are protected under the CARES Act.
  4. Public health updates: More than 400 long-term care facilities across the U.S. report patients with coronavirus — Older adults and people with underlying health conditions are more at risk, new data shows.
  5. Federal government latest: President Trump said the next two weeks would be "very painful," with projections indicating the virus could kill 100,000–240,000 Americans.
  6. U.S.S. Theodore Roosevelt: Captain of nuclear aircraft carrier docked in Guam pleaded with the U.S. Navy for more resources after more than 100 members of his crew tested positive.
  7. What should I do? Answers about the virus from Axios expertsWhat to know about social distancingQ&A: Minimizing your coronavirus risk.
  8. Other resources: CDC on how to avoid the virus, what to do if you get it.

Subscribe to Mike Allen's Axios AM to follow our coronavirus coverage each morning from your inbox.

World coronavirus updates: UN warns of recession with "no parallel" to recent past

Data: The Center for Systems Science and Engineering at Johns Hopkins, the CDC, and China's Health Ministry. Note: China numbers are for the mainland only and U.S. numbers include repatriated citizens and confirmed plus presumptive cases from the CDC

The novel coronavirus pandemic is the "greatest test" the world has faced together since the formation of the United Nations just after the Second World War ended in 1945, UN chief António Guterres said Tuesday.

The big picture: COVID-19 cases surged past 856,000 and the death toll exceeded 42,000 Tuesday, per Johns Hopkins data. Italy reported more than 12,000 deaths.

Go deeperArrowUpdated 2 hours ago - Health

White House projects 100,000 to 240,000 U.S. coronavirus deaths

President Trump said at a press briefing on Tuesday that the next two weeks in the U.S. will be "very painful" and that he wants "every American to be prepared for the days that lie ahead," before giving way to Deborah Birx to explain the models informing the White House's new guidance on the coronavirus.

Why it matters: It's a somber new tone from the president that comes after his medical advisers showed him data projecting that the virus could kill 100,000–240,000 Americans — even with strict social distancing guidelines in place.

Go deeperArrowUpdated 3 hours ago - Health