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One such example of the ocean conveyor belt’s effect on climate is the Gulf Stream. The Gulf Stream flows through the Gulf of Mexico. From there, it travels up along Florida’s eastern coast. This wind-driven surface current pushes warm equatorial water up the eastern coast of the US. The Gulf Stream then moves out toward the north Atlantic, cooling as it travels northward. Once it reaches the north Atlantic, it has cooled enough so that it sinks. This region is called the North Atlantic Deep Water. This warm water from the Gulf Stream has a major impact on the weather and climate of Europe. 

In northern Europe, it would mean an increase in precipitation. Another problem would be if the polar ice caps and large continental glaciers like Greenland started to melt. This event would flood the North Atlantic with a large amount of fresh water. In theory, this action would divert the Gulf Stream. Warm waters coming from the Gulf of Mexico would not reach the British Isles and Europe. Without these currents, Europe’s climate would be seriously impacted. The area would experience cooler temperatures and an increase in rainfall.

Was the slowing of the thermohaline responsible for the Little Ice Age?

The Little Ice Age was a period of global cooling. It started in the fourteenth century and lasted until the nineteenth century. The Little Ice Age caused much distress to agriculture across the globe. This was due to a drop in average temperatures. While it was not a true ice age, it still created great hardship with centuries of cooler temperatures. Scientists are still speculating on its cause.

One theory is that the Medieval Warming Period was a cause of the Little Ice Age. This warming period may have caused Greenland’s glaciers to melt. This melting may have caused an increase in fresh water entering the North Atlantic Ocean. This infusion of fresh water could have altered the thermohaline circulation. If so, this would mean the warm waters from the Gulf Stream would not reach the shores of Europe.