The world’s oceans are warming at a faster rate than previously estimated, new research has found, raising fresh concerns over the rapid progress of climate change. Warming oceans take up more space, a process known as thermal expansion, which the study says is likely to raise sea levels by about 30cm by the end of the century, on top of the rise in sea levels from melting ice and glaciers. Warmer oceans are also a major factor in increasing the severity of storms, hurricanes and extreme rainfall.
Oceans store heat so effectively that it would take decades for them to cool down, even in the unlikely scenario that greenhouse gas emissions were halted urgently.
The report, published on Thursday in the journal Science, found that the warming of the oceans was accelerating and was matching the predictions of climate change models, which have shown global temperature rises are likely to lead to extreme weather across the world. Zeke Hausfather, co-author of the paper and a graduate student at the University of California, Berkeley, said: “While 2018 will be the fourth warmest year on record on the [earth’s] surface, it will most certainly be the warmest year on record in the oceans, as was 2017 and 2016 before that. The global warming signal is a lot easier to detect if it is changing in the oceans than on the surface.”
Oceans absorb more than nine-tenths of the excess energy trapped in the atmosphere by greenhouse gases, and play a key role in regulating the world’s climate. But the role of oceans in the global climate system was overlooked for many years, in part because of a lack of data and the difficulty of studying the marine environment. Only in recent years have scientists come to realise the full importance of oceans, which have effectively absorbed much of the impact of climate change in recent decades, but are now understood to be reaching their capacity as a buffer.