Environment

Earth's Oceans Heating Up Much Faster Than Scientists Expected

A new study provides the first real-world estimate of how quickly our seas are warming.

Climate researchers released a study on Sunday indicating that the Earth’s oceans are heating up at a pace far exceeding what they had expected. The study, published in the journal Nature Climate Change found that the surface layers of the planet’s oceans are warming between 24% and 55% faster than previous estimates.

The study is said to provide the first rough estimate of how much scientists have miscalculated in their previous attempts to measure the changing heat content in our oceans. It should help researchers better understand and model how the Earth’s climate system will respond to changes in greenhouse-gas levels. As the seas absorb 90% of the heat caused by human activity, oceanic heat content is crucially important to climate science.  

The researchers, who have been studying ocean temperatures in the Earth’s southern hemisphere since 1970, are recommending that the scientific community adjust its estimates accordingly. Paul Durack, the study’s lead author, said this is the first time scientists have been able to quantify how big the gap is between previous estimates and the reality of rising ocean temperatures.

This better estimate of ocean heat content also makes it easier for scientists to estimate how the seas will rise over time as glaciers melt and sea water warms and expands.

A critical consequence of ocean warming is acidification of sea water. The ocean chemistry is becoming more hostile to many animals fundamental to the marine food web. Last year, another study in Nature Climate Change showed that acidification is happening at a rate 10 times faster than ever before.

Ocean acidification occurs when pH levels—a measure of acidity—fall in the ocean. The lower the pH, the higher the acid. So falling pH levels in the ocean mean that acid is increasing, which has major effects on species that live in the sea, particularly those that build calcium-based shells.

The observed increase of carbon-dioxide concentrations in our oceans is considered unparalleled in the Earth's history over the past 20 million years. Scientists are uncertain of the extent to which marine fauna can adapt to it over an extended period of time.

“Studies have shown that a more acidic environment has a dramatic effect on some calcifying species, including oysters, clams, sea urchins, shallow water corals, deep sea corals, and calcareous plankton,” the National Oceanic and Atmospheric Administration states. "When shelled organisms are at risk, the entire food web may also be at risk. Today, more than a billion people worldwide rely on food from the ocean as their primary source of protein. Many jobs and economies in the U.S. and around the world depend on the fish and shellfish in our oceans.”

Cliff Weathers is a former senior editor at AlterNet and served as a deputy editor at Consumer Reports. Twitter @cliffweathers.

 

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