Increased energy use ‘hidden’ by deep oceans

New analysis, led by the National Centre for Atmospheric Research (NCAR), claims to show for the first time how ocean layers deeper than 1,000 feet are home to ‘missing’ heat from energy intensive industries around the globe.

Scientists behind the work claim global warming moves in periods which appear to slow or stop for up to a decade, before resuming.

The 2000s were, according to the team, the ‘warmest decade in more than a century’ in terms of weather records.

However, the single-year mark for warmest global temperature, which had been set in 1998, remained unmatched until 2010.

At the same time however, the team claims, emissions of greenhouse gases continued to climb during the 2000s and satellite measurements showed the discrepancy between incoming sunshine and outgoing radiation from the planet actually increased.

The team’s computer simulation showing the global average temperature rising by about 2.5 degrees Fahrenheit (1.4 degrees Celsius) between 2000 and 2100, but with two decade-long hiatus periods during the century.

During these periods simulations showed extra energy entered the oceans with deeper layers absorbing what scientists called a ‘disproportionate amount’ of heat due to changes in oceanic circulation.

Vast areas of ocean below about 1,000 feet will, according to the simulations warm by between 18% to 19% during so-called ‘hiatus periods’ rather than at other times.

In contrast, the shallower global ocean above 1,000 feet warmed by 60% less than during non-hiatus periods in the simulation.

NCAR’s lead author of the study, Gerald Meehl, said: “We will see global warming go through hiatus periods in the future.

“However, these periods would likely last only about a decade or so, and warming would then resume.

“This study illustrates one reason why global temperatures do not simply rise in a straight line.

“This study suggests the missing energy has indeed been buried in the ocean, the heat has not disappeared and so it cannot be ignored. It must have consequences.”

The research was published online in Nature Climate Change yesterday (September 18).

Luke Walsh