In some regions of the planet, processes of global cooling are underway - and they began in the Middle Ages.

Total climate changes associated with global warming contribute to the gradual heating of the waters of the World Ocean. Recently, however, a group of researchers from Harvard discovered a unique region in the Pacific Ocean where the opposite process is in full swing.

According to scientists, the reason for the cooling of the water was the last Little Ice Age, which began around 1500 and lasted until the middle of the 19th century. For a long time, cold masses of water were on the surface, but gradually began to sink to a depth of about 2000 meters. Given the enormous size of the Pacific Ocean, this process can last for hundreds or even thousands of years.

The first oceanographic expedition took place in the second half of the 19th century, when a group of scientists went to the Pacific Ocean aboard the wooden sailing ship HMS Challenger, which took about 5, 000 water temperature measurements at various depths.

Already today, researchers, based on a comparison of the latest data with those obtained by the expedition to the HMS Challenger, were able to track the movement (sinking) of the cold oceanic masses of the Little Ice Age.

The information collected will help scientists better understand the dynamics of planetary climate change and their possible consequences.