"So, just as a refresher, it’s always good to remember that we live on an ocean planet. Most of the Earth’s surface is salt water, studded with the large islands we call continents.
It’s worth recalling this small fact – which can slip our minds, since we humans congregate on the patches of dry ground – because new data shows just how profoundly we’re messing with those seven seas. The International Union for the Conservation of Nature has published an extensive study concluding that the runaway heating of the oceans is “the greatest hidden challenge of our generation”.
When we think about global warming, we usually fixate on the air temperature. Which is spiking sharply – July was the hottest month ever measured on our planet. But as the new study points out, 90% of the extra heat that our greenhouse gases trap is actually absorbed by the oceans. That means that the upper few meters of the sea have been steadily warming more than a tenth of a degree celsius per decade, a figure that’s accelerating. When you think of the volume of water that represents, and then try to imagine the energy necessary to raise its temperature, you get an idea of the blowtorch that our civilization has become."