How do ocean currents affect climate and weather?

Ocean currents play an extremely important role in the climate. Solar radiation is the main source of the earth's heat, but its distribution in different dimensions is uneven, and ocean currents and atmospheric circulation assume the role of redistributing these heat. Without them, the tropics will be hotter and the frigid zones will be colder. This is for the global climate. Specific to a certain area, the circulation around it also has a great influence on the regional climate. For example, one of the reasons why Europe is warmer than many places in the same dimension is the heat brought by circulation.