One of these feedbacks involves ice which keeps the planet cold due to its bright white color by reflecting sunlight back into space. Another problem is CO2, because when it's cold, the oceans absorb more CO2, leaving less in the atmosphere to trap heat. When it gets warmer, the process reverses. In addition to this, ocean currents can also cause regional and global climate changes, as they act like a giant conveyor belt and spread heat around the Earth. El Nino phenomenon affecting regional temperatures and precipitation changes global average.