How Much Are the Oceans Warming?

A new research paper from China has demonstrated that although 2017 was only the second-hottest ever year in terms of land temperatures, it was by far the warmest year on record beneath the waves. The study, published in the journal Advances in Atmospheric Sciences, analysed data from the late 1950s to the present day and provides the clearest proof yet (if any was needed) that global warming is a very real and manmade phenomenon.

An upward trend

While there are many geological markers which signpost the onward march of climate change, these can be difficult to document. Rising sea levels are perhaps the biggest threat to mankind, and while making precise volume measurements is possible in a reservoir or other closed waterway, it’s much more difficult in the ocean. Land temperature gives us a vague idea as well, but as the ocean makes up over two-thirds of the Earth’s surface and stores almost 97% of its water, the majority of heat is trapped here, too.

For their study, the Chinese researchers borrowed figures supplied by the National Oceanic and Atmospheric Administration (NOAA) and the National Centres for Environmental Information (NCEI) stretching back as far as 1958. By mapping out the oceanic temperature for every year on a graph against the average temperature between 1981 and 2010, the researchers were able to demonstrate the true extent of oceanic warming – and the rate at which it is accelerating.

The last five years have been the hottest on record, with 2017 reaching 19.19x10²²J. If that sounds a little difficult to process, one fact can help to put it into context: annual electricity production in the whole of China is 600 times smaller than the rate at which the ocean is currently warming. Clearly, we’re dealing with a runaway phenomenon here that must command immediate attention.

Factors and outcomes

Of course, manmade activity isn’t the only factor affecting oceanic temperature. Natural occurrences such as volcanic eruptions, ocean currents and El Niño / La Niña all play their part in the fluctuating temperature of our seas and oceans, which is why a rise or decrease from one year to another (or even over several years) isn’t proof in itself of global warming. A concerted rise in temperature over several decades, on the other hand, certainly is.

One of the direct outcomes of this heat increase is a rise in sea levels, since water expands as it warms. Indeed, the authors of the Chinese report calculated that the record-breaking temperatures of 2017 probably caused a 2mm rise of sea levels around the world. Meanwhile, Arctic warming results in the emission of greenhouse gases (GHGs) and the melting of the polar ice caps, both of which exacerbate the situation. Meanwhile, the unabated progress of coral bleaching is another natural cause for concern.

All of this means that if the Earth’s oceans continue to warm at their current rate, it won’t be long before flora and fauna beneath the waves is irreversibly compromised by climate change… with those living on land at risk soon afterwards.