The deepest parts of the ocean, with pitch black and nearly freezing waters, are warming. The zone is far from the hazardous human activity of burning fossil fuels, but it’s feeling the wrath nonetheless. Just imagine how much heat is necessary to warm so much water – and water at depths of thousands of feet below the surface!
A study of ten years of hourly measurements found that temperatures are rising quicker than thought. Stations in the Atlantic Ocean, off Uruguay’s coast, recorded temperatures at four different depths ranging from 1,360m (4,462ft) to 4,757m deep. The results reveal that between 2009 and 2019, the waters warmed by 0.02-0.04°C.
While that may not seem like much, it’s significant. Lead author of the study, Christopher Meinen, a US National Oceanic and Atmospheric Administration (NOAA) oceanographer, said:
If you think about how large the deep ocean is, it’s an enormous amount of heat.
The ocean surface and global land temperatures are warming much faster. They were 0.56C higher than the average in 2009 and 0.95C higher by 2019. Another study found that the Atlantic Ocean has reached its hottest point in the past 2,900 years this decade.
About 90% of the heat absorbed by the planet seeps into the oceans. According to climate models, the high levels of climate pollution will penetrate deeper into the sea by the end of the century. When that happens, it will threaten deep-sea creatures.
On the surface, rising temperatures are affecting coral reefs with unprecedented bleaching events. Yet another study found that ocean warming and acidification may eradicate coral reefs by the end of the century if left unchecked. The Great Barrier Reef off the coast of Australia has already lost half of its coral since 1995.
The heat also makes water molecules expand, causing the sea-level rise and intensified hurricanes.
Meinen, speaking for himself and not on behalf of NOAA, said:
We didn’t expect that you would see hour-to-hour and day-to-day variations down that deep. There are processes in the deep ocean that are making things change rapidly, and we don’t really know what those processes are yet.
The new findings are consistent with human-caused climate change. However, more research is needed to make definitive conclusions because there is not enough historical data on the deep ocean, which has not been studied as much as the Earth’s atmosphere.
The data used in this new NOAA study came from a set of instruments the scientists used to study ocean currents. They are pressure sensors with built-in temperature sensors. The scientists point out that to understand long-term trends, the deep ocean temperatures must be taken yearly.
The team hopes its research will inspire others to log temperature data as well if they have such instruments. The more information there is about the deep ocean, the better scientists can forecast seasonal weather patterns. Such knowledge would help farmers better select which crops to plant, among other things.
