2018 Shaping Up As Hottest Year On Record, Thanks To Rapid Ocean Heating; 2017 Likely 2nd-Hottest
Climate change from human activities mainly results from the energy imbalance in Earth's climate system caused by rising concentrations of heat-trapping gases. About 93% of the energy imbalance accumulates in the ocean as increased ocean heat content (OHC). The ocean record of this imbalance is much less affected by internal variability and is thus better suited for detecting and attributing human influences (1) than more commonly used surface temperature records. Recent observation-based estimates show rapid warming of Earth's oceans over the past few decades (see the figure) (1, 2). This warming has contributed to increases in rainfall intensity, rising sea levels, the destruction of coral reefs, declining ocean oxygen levels, and declines in ice sheets; glaciers; and ice caps in the polar regions (3, 4). Recent estimates of observed warming resemble those seen in models, indicating that models reliably project changes in OHC.
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http://science.sciencemag.org/content/363/6423/128.summary
Last year was very likely the hottest year on record, according to the authors of a new study in the journal Science. The study examined “multiple lines of evidence from four independent groups” measuring ocean heat and concluded “ocean warming is accelerating.” Researchers found the rate of warming for the upper 2,000 meters of ocean has increased by more than 50 percent since 1991.
As a result, “2018 is shaping up to be the hottest for the oceans as a whole, and therefore for the Earth,” a press release accompanying the study explains.
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As co-author Kevin Trenberth, a distinguished senior scientist in the Climate Analysis Section at the National Center for Atmospheric Research, told ThinkProgress, “global warming is close to ocean warming and 2018 will be the warmest year on record, followed by 2017.” Trenberth, a leading expert on the connection between climate change and extreme weather, pointed out that “one of the warmest spots was where Hurricane Florence developed this past year [in the Atlantic] and where Hurricane Harvey developed the previous year [in the Gulf]. The warm water fuels the evaporation and moisture for storms.”
It is “too late to stop ocean warming in this century because ocean response” is so slow, warned Cheng. Water stores a lot a heat, so its temperature fluctuates much more gradually. But, she said, we can slow the rate of warming if we “act as soon as possible to reduce carbon emission.”
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https://thinkprogress.org/study-2018-is-shaping-up-to-be-the-hottest-year-on-record-as-ocean-warming-speeds-up-a08a85c8438a/
