Nonprofit, nonpartisan journalism. Supported by readers.


New ocean data disprove any slowdown in the rate that our planet is warming

The measurements can be “noisy,” explains St. Thomas professor John Abraham, but the warming signal within them is clear.

The southern hemisphere is warming more slowly, and that is due to the fact that it’s almost all ocean.

Second of two parts.

Few things are more disappointing to a journalist than the interview so bad it produces no insight worth writing about — or more frustrating than the interview which produces more good material than can possibly be crammed into one piece.

Article continues after advertisement

The conversation I had earlier this week with John Abraham, an engineering professor at the University of St. Thomas, fit so squarely in that second category I simply had to write it up as a two-part post.

Yesterday’s article discussed the findings in a paper Abraham co-authored that recent warming of the oceans had been underestimated by as much as 13 percent, and that the rate of seawater’s rise in temperature is accelerating.

That’s a pretty big deal, because the oceans hold more than 90 percent of the excess heat that is warming the planet and driving climate change.

Today we turn to some related topics:

  • How the differential rates of ocean warming around the world might relate to on-land effects.
  • What the new analysis shows about the much-debated “pause” or “hiatus” that some think was apparent in air-temperature data through the previous decade.
  • How Abraham’s engineering background leads him to approach climate science somewhat differently, and informs a spirit of optimism about the fix we’re in.

One finding of the paper, published last week in the American Association for the Advancement of Science’s journal Science Advances, was that seawater is warming more rapidly in the southern hemisphere, and in the tropical/subtropical portions of both the Atlantic and Pacific Oceans. I wondered how that correlated with trends in air temperatures.

The southern hemisphere is warming more slowly, and that is due to the fact that it’s almost all ocean. Most of the land is in the northern hemisphere, and the land warms much faster than the ocean because the oceans can store that heat at such depths.

And that’s another reason why the ocean heat content should be seen as a better indicator of what’s going to happen with climate change than the air-temperature measurements.

No ‘hiatus’ after all

At several points the paper mentions the “global warming hiatus” or “so-called hiatus” but the references struck me as just a little opaque on how the new findings relate to that debate, so I asked Abraham if he could make this plainer.

The “so-called hiatus” is a supposed slowing down of global warming from 1998 to 2013. It turns out our research shows there was never a hiatus. The earth continued to warm at a more or less constant rate.

This is a signal-to-noise problem: People thought there was a hiatus because the temperatures measured in the atmosphere jump around a lot — they’re noisy. But if you look at the underlying warming rate, taking the ocean into consideration, the hiatus never existed. The ocean continued to warm. That’s the signal, and it’s clear.

But even apart from the ocean’s role, I wondered, wasn’t there considerable disagreement over whether the air temps themselves showed any real slowing?

Yes! There is debate about that! I had a paper out in 2015, and in it we showed that any slowing wasn’t statistically significant. Any apparent slowing was so small it could be seen as random chance.

Since then there have been four other studies that have asked the same question, of whether there was a slowdown. One of them took the temperature data and presented them as commodity prices — I think they said the commodity was bananas — and sent these to economists with a letter stating, “We’ve received a claim that banana prices have stopped rising — that there’s been a hiatus.” And the economists, to a person, said there was no justification for such a claim, there was no hiatus.

They were split, though, over whether the claim was maliciously deceptive.

The engineering view

Courtesy of John Abraham
Abraham in Uganda

I asked Abraham if he felt there were ways in which he approaches inquiry about climate questions differently, as an engineer, than collaborators from such disciplines as oceanography or atmospheric physics.

Yeah, there are.  How I got into this in the first place is, I’m a fluid mechanics and heat transfer expert. I was talking to an oceanographer and he was talking about these heat sensors they drop into the ocean and he said, they go down and come back up and we don’t really understand the fluid mechanics around the sensor, the drag they experience, and so forth, and so I got involved in improving the quality of the measurement.

I was approaching the problem on a small scale — the fluid flow and heat transfer in the near vicinity of these sensors. There aren’t many climate scientists or oceanographers that have that kind of expertise. And what I like to do is marry my expertise on local phenomena with climate scientists’ specialty in global phenomena.

That led naturally to wondering if Abraham also works on ways we might engineer our way out of the globe-warming mess we’ve created.

I sort of do. My climate work is all pro bono. My funded research is in biomedicine and energy. So I have worked on a number of products that develop power in a clean and sustainable way. I helped invent a wind turbine that can be attached to cell towers, off grid or in the developing world, to provide power to the electronics on a cell tower so you don’t need a grid connection.

I installed solar panels in a remote village in Uganda that had never had electricity. And right now I’m working on a product we’ll bring to Uganda at the end of this week that pasteurizes water using solar power. Pathogens are the number two killer of kids under 5, so we’re going to give them a way to boil water with solar power.

As scientists, we’re driven by wanting to understand things — we want to know why. And as engineers, we want to be able to do. We want to be able to solve problems. And I’m lucky enough that I’ve been able to work in both areas.

And optimism prevails

As I often do, I moved to end the interview by offering Abraham the opportunity to answer any questions I hadn’t thought to ask:

This paper is another piece of science that shows us what is happening, but we don’t answer the question of what we can do about it.

However, my own expertise in energy tells me that we can solve these problems with today’s technology in a way that improves our economy, our national security and diversifies our energy supply.

And I think that’s the lasting message: This is not an intractable problem, but a problem we can solve with American technology.

* * *

This paper, “Improved estimates of ocean heat content from 1960 to 2015,” can be read and downloaded here [PDF] without charge.