2017 Hottest Year On Record For Earth's Oceans; Past Five Years Five Hottest Years On Record
Where does most of the heat trapped by human fossil fuel and other greenhouse gas emissions ultimately end up? Given our fixation on global surface temperatures, many people would say ‘the atmosphere.’ But this answer is incorrect. The vast majority ends up in the world ocean.
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(Global change in ocean heat content through 2015. Image source: Skeptical Science and CMIP5.)
The world ocean system is the largest heat sink on our planet’s surface. This is due to the fact that liquid water contained in the oceans both has a far greater mass and overall heat capacity than the atmosphere. Just a fraction — less than 1/30th of the heat trapped by human-emitted greenhouse gasses ends up in the atmosphere. Similar portions end up getting soaked in by the land and by melting glaciers. The rest, about 90 percent, finds its way into the oceans.
The ocean is thus the best, most reliable global thermometer available. For good reason, most scientists wait for readings from this big, wet thermostat to get an idea where global temperatures are headed and how fast. And what some of the world’s top ocean researchers found this week was that during 2017 the top 6,000 feet of the world’s oceans experienced their hottest year ever recorded.
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(Ocean heat content change since 1958. Illustration: Cheng and Zhu (2018), Advances in Atmospheric Sciences.)
EDIT
It’s worth noting that ocean heat gain is presently both quite rapid and rather steady. All of the past five years were each one of the five hottest ocean years ever recorded. Global temperature gain thus hasn’t slowed. And though atmospheric temperature gain has accelerated during recent years, the ocean measure hints that overall heat gain per year has been pretty steady since the mid 1990s. At least for the top 6,000 feet of the world’s surface waters (though other measures provide some hints at acceleration [see image at top of this post]). An observation that would seem to reinforce the present decadal rate of temperature increase in the range of 0.15 to 0.20 C every ten years or about 30 to 50 times faster than the warming that ended the last ice age.
To be clear, the primary driver of what is a very rapid warming in the geological context is human fossil fuel burning and related carbon emissions in the range of 11 billion tons per year. Halting fossil fuel burning is therefore critical to slowing down and ultimately stopping the present rate of warming and dangerous related atmospheric and ocean carbon addition.
EDIT/END
https://robertscribbler.com/2018/01/26/not-even-the-briefest-of-pauses-for-human-forced-global-warming-oceans-during-2017-were-the-hottest-on-record/#comments
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