After a major shift called Mid-Pleistocene Transition glacial periods became more intense, and formed ice-sheets to give Earth regular ice-age cycles which is still prevailing.
A million years ago, something big has happened in our planet which shifted the response of Earth’s climate system. This shift is known as Mid-Pleistocene Transition.
Glacial periods became so intense after this transition that they have formed ice sheets in the Northern Hemisphere which lasted for nearly 100,000 years.
Scientists were trying to find out the reason behind this and they have credited a phenomenon named Milankovitch cycles for it.
Milankovitch cycles are Earth’s orbit and orientation of the Sun and its way to affect the energy that Earth absorbs in a cyclical way from sun.
The scientists have agreed that this was the main cause for alternating warm and cold periods for millions of years. Though scientists have found out that Milankovitch cycles haven’t gone through any kind of big change, so there was something else at work too, which we will call Atlantic Meridional Overturning Circulation.
Atlantic Meridional Overturning Circulation is a system of ocean currents which helps in moving the heat of the ocean around the globe. In this system, the ocean current moves the heat to north through Atlantic Ocean is known as Atlantic Meridional Overturning Circulation.
The researchers have analysed the water of deep sea of south and north Atlantic where the water has left chemical clues.
Ice sheets of Northern Hemisphere started to stick to their bedrock more effectively and the glaciers became thicker which caused a greater global cooling than ever. This has disrupted the Atlantic heat conveyor belt.
The research has also proven that the gradual removal of slippery continental soils enabled the ice sheets to cling more tightly with one another. This change has contributed to shape the global climate before the weakening of the AMOC.