Warming on Land is Only One-Tenth of the Climate Change Story
While a single degree Celsius of atmospheric warming over land has been enough to melt mountain glaciers, bake urban populations, and enflame wildfires that threaten rural communities, most of the extra heat being trapped on Earth by greenhouse gases is actually going to a destination that shore-bound humans too seldom consider: the world’s oceans.
Water covers two-thirds of the planet, and its greater thermal mass than air means more than 90% of the extra heat being captured inside the greenhouse blanket is in fact being absorbed by the oceans. Now Inside Climate News reports just how far, and how fast, the oceans are heating up as a result.
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“The excess energy amassed in the oceans since 1992 is roughly equivalent to 2,000 times U.S. electricity generation during the past decade,” InsideClimate notes, with heat penetrating ever more deeply into the water column. Over the last half-century, ocean temperatures have been rising about 0.12°C per decade.
“The higher temperatures are driving marine life toward the poles in search of liveable habitats, bleaching coral reefs, and causing severe impacts on fisheries and aquacultures,” ICN states. “They also contribute to more frequent and intense extreme weather events. In the three back-to-back deadly hurricanes of 2017—Harvey, Irma, and Maria—warmer waters played a role in worsening the storms.”
InsideClimate republishes four telling graphs drawn from a paper published last month in the American Geophysical Union journal Eos. Its seven authors, led by Lijing Chen of the Institute for Atmospheric Physics in Beijing, include Kevin Trenberth, head of climate analysis at the U.S. National Center for Atmospheric Research.
In the Arctic and Antarctic, Trenberth said, floating ice shelves that currently contain land-based ice sheets are “being undermined through warmer ocean underneath the ice, which is contributing to the thinning and weakening of the shelf.” That accelerates the release of water currently frozen in land-based ice sheets into the oceans.
But according to the researchers, that accounts for only half of the sea level rise taking place today, from New Orleans to Bangladesh. Thermal expansion of the existing water in the oceans contributes the rest.
“The accumulation of heat in the oceans,” ICN notes, provides “the strongest evidence of how fast Earth is warming due to heat-trapping gases released by the burning of fossil fuels.”