Why can ocean currents regulate the climate on the earth?

The largest ocean current in the world is hundreds of kilometers wide in Qian Qian, 100 meter long and hundreds of meters deep. The current in the ocean is very large, and it doesn't all flow in the same direction. Open a hydrograph, and you will find that the earthworm-like curve above represents the general route of seawater flow. They are connected end to end and go back and forth. This is the circulation on the ocean surface, which we figuratively compare to "the blood of the ocean". It is precisely because of the movement of ocean currents, which are constantly flowing from south to north, and play an important role in the transportation and exchange of ocean thermal energy at high and low latitudes and the global heat balance. So as to regulate the climate on the earth.