Science

What do Earth's magnetic fields tell us about warming oceans?

What do Earth's magnetic field...
Warmer oceans can spell trouble for the organisms that call them home
Warmer oceans can spell trouble for the organisms that call them home
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Warmer oceans can spell trouble for the organisms that call them home
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Warmer oceans can spell trouble for the organisms that call them home
Scientists are working on a technique to use satellite observations of magnetic fields to measure heat stored in the ocean
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Scientists are working on a technique to use satellite observations of magnetic fields to measure heat stored in the ocean

Originating in our planet's core and ballooning out into space, the Earth's magnetic field has long kept humans safe from charged particles and deadly radiation, and it turns out it might also know a thing or two about our future well being. By tracking deviations in the field as it passes through the ocean, scientists say it is possible to gauge the temperature changes in the sea, helping to fill in important detail about how our planet is responding to global warming.

Much of the warmth we are adding to the Earth system is absorbed by the ocean – as much as 90 percent according to Tim Boyer, a scientist at the National Oceanic and Atmospheric Administration's National Centers for Environmental Information. Rising temperatures in the sea can have all sorts of consequences for the life within, such as coral bleaching, but tracking how much we are cranking up the heat isn't all that straightforward.

Currently, scientists track ocean temperatures through ship measurements, a global network of drifting monitoring stations called Argo floats, and even tagged, free-roaming seals. Even so, the picture of temperature changes in this huge environment is far from complete.

"Even with the massive effort with the Argo floats, we still don't have as much coverage of the ocean as we would really like in order to lower the uncertainties," says Boyer. "If you're able to measure global ocean heat content directly and completely from satellites, that would be fantastic."

Such an approach may well be possible, thanks to a combination of geophysical features and some clever thinking on part of scientists at NASA's Goddard Space Flight Center.

Scientists are working on a technique to use satellite observations of magnetic fields to measure heat stored in the ocean
Scientists are working on a technique to use satellite observations of magnetic fields to measure heat stored in the ocean

The concept begins with the fact that seawater conducts electricity. This means that as it moves around the ocean, it actually sways the magnetic field lines running from the Earth's core out into space. And because the conductivity of the water is influenced by its temperature, scientists believe it is possible to use satellite data to monitor these fluctuations and pin down how much the ocean might be warming.

The scientists are presenting a proof-of-concept study at the American Geophysical Union in San Francisco this week, demonstrating that with some computer modeling, temperature measurements can be drawn from these shifting magnetic signals. The technique is still in its early stages, however, with the researchers keen to iron out some sizable kinks in the modeling, such as identifying fluctuations caused by other ocean movements like eddies. But with further refinement, the researchers hope that the technique can come to offer a way to track global ocean temperatures across all depths.

"Even with the massive effort with the Argo floats, we still don't have as much coverage of the ocean as we would really like in order to lower the uncertainties," Boyer said. "If you're able to measure global ocean heat content directly and completely from satellites, that would be fantastic."

The animation below offers a brief overview of the approach.

Ocean Tides and Magnetic Fields

Source: NASA / Video: NASA's Goddard Space Flight Center/Matthew Radcliff

5 comments
Bob
OK. While there may be some merit in this approach, I seriously doubt it will be accurate enough to prove anything but preconceived assumptions. The problem with most mathematical models is that they are only accepted if they agree with a preconceived belief. The second big problem is that models, like statistics, are useful tools but can be easily skewed to support any assumption or agenda. An thirdly, models never contain all the needed variables nor weight them correctly. Sadly, the only people who understand what I am saying are those who develop the models. Even perfect equations do not purify incorrect, biased or missing data.
DraganCake
I supposes these geniuses never took into consideration that the changes in our magnetic field (and there have been significant ones over the past few years) could be contributing to the oceans warming?
Some people can't see the forest for the trees and it would be nice if an agenda wasn't placed into all this "science" before any conclusions were drawn.
Brian M
Nice idea/concept but fraught with so many unknowns both in the model and measurement accuracy. Looking at magnetic models of the earth , the words anomalies is never too far away! But maybe at a global level they may average out?
Robert in Vancouver
I have lived 25 metres away from the Pacific Ocean for the last 48 years and swear on the Bible that there has been no change to the sea level. No change. But enviro-nuts and the media keep spreading lies that sea levels are rising and we are all doomed unless we pay a carbon tax. I'm sick of their BS.
MartinVoelker
@ Robo -- Sea levels in different places are influenced by a host of regional and local factors, as well as short- and long-term oceanographic trends. That's why we rely on a global network to measure sea level with different instruments, rather than on the claim (however anecdotally true) of a single oceanside Bible owner. Also, roughly half of the past century's rise in sea level is attributable to warmer oceans simply occupying more space, aka thermal expansion. And please don't insult Phd scientists who successfully defend their findings and methodology against their nitpicking peers as eco nuts.