Mid-Pliocene Arctic Warmer than Today Due to Ocean Currents
10.02.2011 - Water & Oceans, Land & Geology, Arctic
Research published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology offers a new explanation for why the Arctic was warmer than today during the Mid-Pliocene (about 3 million years ago).
The climate in the mid-Pliocene is a reference point for climate conditions today, as it had a similar global average temperature and levels of carbon dioxide in the atmosphere. However the major difference between then and now is that the Arctic was much warmer. The research findings conducted by researchers from the US Geological Survey (USGS), the British Geological Survey (BGS) and several universities in the United Kingdom, suggest that the reason for this difference could be due to a group of underwater ridges and channels that extend from Greenland to Scotland known as the Greenland-Scotland Ridge.
The ridge is a geological hotspot where mantle comes up from the Earth. As the Earth’s crust on the ridge warms and cools, it expands and contracts, changing its height. Today, the ridge traps North Atlantic Ocean water as it sinks to lower depths, redirecting it back towards the equator. However during the mid-Pliocene, the ridge was about 300 metres lower, which allowed deep ocean currents to flow freely. This ultimately increased the flow of warm surface water, leading to the unusual warming in the North Atlantic and the Arctic.
While the research team still needs to run more accurate trials, this new discovery will greatly improve models of climate during the mid-Pliocene.
