Ocean Heat Record Broken ... Again
Despite La Nina's cooling effect ...
Happy New Year!
Updating my report from a few weeks back on the increasing heat energy being stored in our oceans. It’s the “smoking gun” for climate change.
A paper just published tells us that the amount of energy stored in the World’s Oceans - otherwise known as the Global Ocean Heat Content (OHC) - increased again last year, despite the otherwise cooling La Nina conditions that have prevailed for the last couple of years. The world ocean, in 2021, was the hottest ever recorded by humans, and the energy stored increased last year by about 15 Zetta joules (1 Zetta J = 10^21 J).
That’s 15,000,000,000,000,000,000,000 joules, or about 4,200,000,000,000,000 kilowatt hours. If I’d personally used that amount of electrical energy last year it would have cost me about NZ$1,000,000,000,000,000 (about a million billion kiwi dollars, or NZ$10^15).
C’mon Substack. When will your editing tools allow superscripts for scientific notation? I’m tired of using that ‘^’ symbol. It reminds me of the days of DOS.
Anyway, I think we can agree that it’s a LOT of energy.
The increased ocean heat content comes from the additional trapping of energy by greenhouse gases. Prior to the 1980s - when estimates first became available - the Ocean Heat Content (OHC) was at least 300 ZJ less. The upper panel in the graph below shows that inexorable increase.
The lower panel above compares shorter term changes in Ocean Heat Content (after the long term trend has been removed) with the El Nino Southern Oscillation Index (ONI). In this de-trended data, a negative index tends to be associated with periods of lower ocean heat content. But in the last couple of years the mean heat content was above average despite that index being negative.
The ocean heat content data come from thousands of submersible buoys that have been deployed over the oceans of the world.
The numbers are so big that they’re hard to comprehend. Had you ever heard of Zettajoule before this?
How do they compare with the total amount of energy mankind uses? Well, in 2018 (the most recent year for which I found data) we consumed about 170,000 TWhr, about 15 percent more than a decade before. So, in terms of joules (where 1 J = 3.6 x10^3 Whr), our energy use is about 6 x 10^20 Joules, or 0.6 ZJ. With that rate of use increase of 1.5 percent per year means that in 2021 we used 0.01 ZJ more than in 2020.
So the extra amount of energy being trapped per year in our oceans far exceeds our energy use! Something must be very inefficient.
By the way, here’s a plot from Hansen’s last update on temperature changes over land and ocean. Because of the La Nina, 2021 wasn’t a record. It was only 6th warmest ever (and the temperature in nearly all of the last ten years has exceeded the maximum prior to that decade).
No good news there I’m afraid. Temperature changes in the atmosphere are more than three time faster than in the oceans. A point I alluded to a few weeks back.
For what its worth, our temperatures here in New Zealand’s last year WERE the hottest on record (despite the La Nina). In fact, the whole of the Southern Hemisphere reached record temperatures last year.
Lets hope for better news next year …
Thanks for reading this. Previous posts on the intersection between Ozone, UV, Climate, and Health can be found at my UV & You area at Substack. Click below to subscribe for occasional free updates.