Warm 'Blob' of Hot Water Bigger Than Texas Heading Towards South America

A warm "blob" of hot water reported to have formed in the Pacific Ocean near New Zealand is making its way towards South America.

An image from Climate Reanalyzer (a website produced by the Climate Change Institute at the University of Maine) made headlines this week after its weather maps showed a patch of unusually warm water in the South Pacific on Monday.

According to a report in The Guardian, the patch is around one million square kilometres and approximately 1.5 times the size of Texas.

The conditions were brought on by a combination sunny skies, high pressures and gentle winds, James Renwick, a professor in physical geography and a weather and climate researcher at the Victoria University of Wellington, told the New Zealand Herald.

"Sea temperatures don't actually vary too much and a degree [Celsius], plus or minus, is quite a big deal and this area is probably four degrees or more than that above average and that's pretty huge," said Renwick.

The center could be more than 6 degrees Celsius hotter than average—making it "one of the warmest spots on the planet at the moment."

At the time of writing, Climate Reanalyzer shows the warm patch in the Pacific part way between New Zealand and southern Chile.

The warmest region (of 4 degrees Celsius or higher) is around 1 million square kilometers—which is bigger than the states of New York, California and Colorado combined. The ocean currents are gradually drifting the "blob" eastwards with the ocean currents.

Global See Temperature
Image from Climate Reanalyzer (https://ClimateReanalyzer.org), Climate Change Institute, University of Maine, USA. Climate Reanalyzer

New Zealand is in the southern hemisphere and, therefore, in the midst of summer, but marine heatwaves like these can just as easily occur in winter.

A marine heatwave is defined according to differences in expected temperatures—which will vary depending on geography and the time of year.

Climatologist Nick Bond from the University of Washington told NOAA Research they are in almost all cases unusual weather patterns "that either cause more heat than usual to go into the ocean, warming up the surface, or in some cases suppress the amount of heat coming out of the ocean."

Between 2014 and 2016, a patch of unusually warm water later nicknamed "the blob" struck the west coast.

These unusual weather patterns can affect the distribution and development of sea-dwelling creatures, and even the ecosystems themselves. According to MarineHeatWaves.org, a heat wave that hit Western Australia in 2011 resulted in higher levels of more tropical-like fish and a shift from kelp forests to seaweed turfs.

As with many lone incidents, it is hard to categorically attribute an extreme or unusual weather event to climate change. However, research suggests that just as land-based heatwaves are becoming more frequent and more intense on the back of global warming, marine-based heatwaves are doing the same.

A 2018 study published in Nature found that worldwide, the frequency and intensity of marine heatwaves increased by 34 percent and 17 percent between 1925 and 2016. The result was a 54 percent increase in the number of days with marine heatwaves.

As for New Zealand, this is not the first marine heatwave to strike in recent years. During the country's hottest summer on record (2017/18), some of the waters around New Zealand reached temperatures 6 to 7 degrees Celsius above average.

In May 2018, there were reports that an unusually warm spell brought tropical visitors from Australia. The Queensland groper (or giant groper) travelled over 1,800 miles to the Bay of Islands, north of Auckland, The Guardian reported at the time.

The article has been updated to include the size of the marine heatwave.