Current global climate change is causing the oceans to heat up at an alarming rate according to the theories generally accepted today. However, new research shows that not all water in all oceans actually gets warmer.
One region is actually getting colder in the depths of the Pacific Ocean, new research suggests. This decrease in temperature in the depths of the ocean is also caused by climate change, but not the modern one with which we are so familiar. In fact, this cooling is caused by a small ice age that happened just hundreds of years ago.
The Little Ice Age began around 1500 and lasted until the mid-19th century. This cooling followed the so-called Medieval Warm Period, after which much of the planet became significantly colder. The cooling affected, among other things, the water on the surface of the Pacific Ocean, which, as scientists assume, as a result of convection began to sink to the bottom - where it is at the moment.
The Pacific Ocean is so large that it can take a long time for this cold water to sink - the process can take hundreds or even thousands of years. A group of researchers from Harvard discovered cold water from the Little Ice Age in the deep underwater area of the Pacific Ocean, where it still sinks and cools everything around.
“While the surface ocean has cooled throughout the second half of the past millennium, those parts of the ocean that are most isolated from modern warming continue to cool,” lead study author Jake Gebbie said in a press release.
More than a hundred years ago, a group of scientists went on an expedition to the Pacific Ocean to collect temperature data. From the wooden sailing ship HMS Challenger, 19th century scientists lowered thermometers into the ocean and collected about 5,000 water temperature measurements at various depths.
Since then, modern researchers have compiled even more detailed ocean temperature data, and by comparing current data with this historical Challenger data, researchers have been able to track the movement of this colder water from the Little Ice Age. This water is currently about one quarter of a mile from the surface.
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With this data, scientists can get a clearer picture of what the world was like during the Little Ice Age. But this study also illustrates the consequences of our own episode of climate change.
If parts of the oceans can remain cold for hundreds of years after a small ice age, then what will happen to the oceans when the planet warms up? How long will this warming last in the depths of the ocean? If the authors of the study came to the correct conclusions, then the consequences of the current global warming, our descendants will be recorded hundreds of years later.