Parts of the Atlantic, Pacific, and Indian Oceans all hit the record books for warmth last month, according to the U.S. National Centers for Environmental Information. The high temperatures, particularly in the tropics, will help in forecasting the fierceness of the Atlantic hurricane season, and “the eruption of wildfires from the Amazon region to Australia, and whether the record heat and severe thunderstorms raking the southern U.S. will continue.” The entirety of the tropical ocean is overheated noted Michelle L’Heureux of the US Climate Prediction Center.
Overall, the five warmest years in the world’s seas, as measured by modern instruments, have occurred over just the last half-dozen or so years. It’s “definitely climate-change related,” said Jennifer Francis, a senior scientist at the Woods Hole Research Center in Massachusetts. “Oceans are absorbing about 90% of the heat trapped by extra greenhouse gases.”
Worldwide, sea temperatures were 1.49 degrees Fahrenheit above average in March. That’s the second-highest level recorded since 1880 for the month of March, according to U.S. data. In 2016, temperatures were 1.55 degrees above average.
The searing global temperatures this year can also be traced back to intense climate systems around the Arctic that bottled up much of that region’s cold, preventing it from spilling south into temperate regions. Combined with global warming, this was a one-two punch for sea temperatures that’s brought them to historic highs.
One of the best-known examples of how oceans drive global weather patterns is the development of the climate system known as El Nino. It occurs when unusually warm waters in the equatorial Pacific interact with the atmosphere to alter weather patterns worldwide. In the Atlantic, for instance, El Ninos can cause severe wind shear that can break up developing storms with the potential to become dangerous hurricanes.
This year, the chance of an El Nino developing is small, and scientists are theorizing one reason could be that climate change is warming all the world’s oceans. El Nino “depends on contrasts, as well as absolute values of sea-surface temperatures,” according to Kevin Trenberth, a scientist at the National Center for Atmospheric Research.