It is believed if we stay below 2 degrees Celsius of global warming it seems unlikely that the Gulf Stream would tip and cause crisis, but if we hit 3 or 4 degrees of warming the chances for the tipping rise. Staying below 2 degrees Celsius (3.6 degrees Fahrenheit) is a goal of the Paris Agreement, which the U.S. just rejoined. If the tipping point is crossed and the AMOC halts, it is likely the Northern Hemisphere would cool due to a significant decrease in tropical heat being pushed northward. But beyond that, science does not yet know exactly what would happen. In 20 to 30 years it is likely to weaken further, and that will inevitably influence our weather, so we would see an increase in storms and heatwaves in Europe, and sea level rises on the east coast of the US" says Stefan Rahmstorf, of the Potsdam Institute for Climate Impact Research.