The world's oceans are heating up at an alarming pace, and scientists aren't sure what to do.
Climate scientists have warned for years that the effects of global warming may be delayed due to the ocean’s tendency to absorb the sun’s radiation, storing heat miles below the surface. According to a report from the Guardian, a recent study published in the journal Nature Climate Change reveals just how much heat has been absorbed by the ocean so far, and how long it will be before it becomes a huge problem.
Scientists found that the vast majority of additional absorbed heat in the ocean exists toward the bottom, 35 percent of which can be found deeper than 700 meters below the surface. Over the past 20 years, the solar radiation warming the ocean’s floor has increased by nearly 15 percent.
Ocean water can absorb a significantly larger amount of radiation than air, which is why average global air temperatures have not fluctuated a great deal in recent decades. It has the capacity to absorb over 90 percent of the excess heat and almost 30 percent of the carbon dioxide emitted by human activity, namely the combustion of fossil fuels.
The Southern Ocean, for example, was found to have absorbed 1.2 billion tons of carbon in 2011. This is nearly the same as the amount emitted by the entire European Union in a year. Whether it’s carbon dioxide or heat energy, the ocean acts as a great depository for the air’s contents.
Scientists working with the NOAA at the Lawrence Livermore National Library examined the changes in heat content across multiple depths throughout the world’s oceans and compared their findings with models that date as far back as 1865.
Ocean temperature data was collected starting in the 1870’s by the HMS Challenger expedition, and historical data shows that the heat content in the upper ocean (700 meters or less) has shot up by a factor of 32 since the dawn of the industrial revolution.
Today, temperature data is collected from a vast network of Argo floats that can measure heat at any depth. The study showed that the heat content in the deepest reaches of the ocean has risen by “several tenths of a degree.” While this is still less than the average 0.5 degrees C that the upper ocean has warmed by, scientists still warn that the increase in deep water has the potential to become a huge problem.
It remains unclear how the massive increase in heat energy in the deepest parts of the ocean will affect global fish stocks, weather patterns, and marine ecosystems, but the study confirms that the amount of heat in the ocean is increasing at a growing rate.
A press release describing a previous study that explains how the increasing heat in the deep ocean affects global warming can be found here.