Step-by-step explanation:
A climatology lecturer of mine once told me that the cold water coming off the melting icecaps may shut down or slowdown the thermohaline circulation of the North Atlantic current. This could trigger localised cooling in the North Atlantic, particularly affecting countries such as Ireland, Britain and the Nordic countries that are warmed by the North Atlantic drift. The chances of this occurring are unclear; there is some scientific evidence for the stability of the Gulf Stream but also a weakening of the North Atlantic drift. However there is also evidence of warming in northern Europe and nearby oceans, rather than the reverse (which would be expected if this theory is correct). Once this was pointed out to him, he stated that the cold water may cause the current to ‘switch off’ rather than cool down slowly. Core samples have shown us that the last ice age caused the North Atlantic Drift to slow down, but it is thought that its path changed between then and now. However, the study of past climate shows that the Gulf Stream has stopped completely several times in the past, causing rapid climate change.