According to research by experts from the University of Colorado Boulder, more and more fresh water has been entering the Arctic Ocean over the past two decades. If this trend continues, the freshening of the North Atlantic could disrupt ocean currents, the authors of the study fear. During the last ice age, the Earth experienced the highest increase in CO2: 14 parts per million in just 55 years. Deep beneath the ice of Antarctica, a giant river system has been discovered that existed 40 million years ago.