The ocean currents that redistribute heat, cold and precipitation between the tropics and the northernmost parts of the Atlantic region are predicted to shut down around the year 2060. This is assuming the current greenhouse gas emissions persist.
What is of interest with the report is that the conclusion, which is based on new calculations, contradict the assessment from the Intergovernmental Panel on Climate Change (IPCC).
The new calculations come from the University of Copenhagen. The researchers predict the system of ocean currents will stop based on the use of statistical tools and ocean temperature data, drawn from the last 150 years.
Their analysis is of the Thermohaline Circulation or the Atlantic Meridional Overturning Circulation (AMOC). Here deep-ocean currents are driven by differences in the water’s density, which is controlled by temperature (thermo) and salinity (haline). The Thermohaline Circulation has operated in its present mode since the last ice age. The thermohaline circulation plays an important role in supplying heat to the polar regions, and thus in regulating the amount of sea ice in these regions.
The thermohaline circulation is critical for maintaining the relatively mild climate of the North Atlantic region.
The researchers state they are 95 percent certain that the collapse will occur between 2025 and 2095. The strongest predictor is in 34 years’ time (2057).
This creates two climate change issues. While much of the world is set to continue to heat up, Europe is likely to see more colling and precipitation. The shutdown will also exacerbate global heating, contributing to an increased warming of the tropics.
In contrast, the latest IPCC report, based on climate model simulations, considers an abrupt change in the thermohaline circulation very unlikely during this century.
To draw their conclusions, the researchers analysed sea surface temperatures in the North Atlantic from 1870 to present days. These sea surface temperatures are types of “fingerprints”, providing an indication of the strength of the thermohaline circulation.
Abrupt climate jumps between the present state of the thermohaline circulation and the collapsed state has been observed to happen 25 times in connection with ice age climate. These are the famed Dansgaard-Oeschger events.
The research is featured in the journal Nature Communications, tiled “Warning of a forthcoming collapse of the Atlantic meridional overturning circulation.”
