The Global Conveyor Belt is a series of ocean currents that move water around the world! Currents are rivers of moving water that are caused by differences in density. Density is how close molecules are packed together in an object. The density of water is impacted by salinity (how much salt there is) and temperature. The more dense water sinks to the bottom and the less dense water goes to the surface of the ocean. This movement causes currents to move around the world. The Global Conveyor Belt is made up of even smaller currents that take water from the bottom to the top of the Earth. The Global Conveyor Belt takes over 1,000 years to fully cycle through. The Global Conveyor Belt’s circulation takes so long because the water in the currents moves at a slow pace, which means that it takes a long time for the water to get around the world.