From the mid-1990s to the early 2000s, there was an odd occurrence in which it seemed like global warming just so happened to stop. One reason for that is the Atlantic Meridional Overturning Circulation, which is Earth’s natural air conditioning unit. It is pretty much the flow of hot and cold water in the ocean forcing warmer waters to flow north bringing more heat to places such as Europe. Without the Atlantic Meridional Overturning Circulation, Europe would almost be too cold to be inhabitable.
There are multiple theories being suggested saying that this could lead to a huge climate change where fresh water from melted ice glaciers might displace warmer water in the surrounding oceans forcing it further south. This will create a paradoxical effect creating a colder climate for all locations affected. Others argue that this will not happen with the extreme spike in greenhouse gases; our output of greenhouse gas could be too much for the AMOC to undo.
It can be shown that when the AMOC weakens, it can cause global spikes in temperature. It is shown that from 1975 to 1998, the AMOC was significantly weaker and this was first when global warming was noticed. In 1998 to 2004, the AMOC had significantly strengthened which is the reason why the temperature of the surface of the Earth had decreased at that time, but after 2004 the AMOC had weakened again which is why 9 out of the last 10 years have been the hottest on record.