Melting icebergs in the Antarctic are key to the process that leads to an ice age on Earth, scientists have said. It has long been known that ice age cycles are paced by periodic changes to the Earth’s orbit of the sun, which changes the amount of solar radiation that reaches the Earth’s surface. But until now, it has been a mystery as to how small variations in solar energy can trigger dramatic shifts in the climate on Earth. Scientists at Cardiff University now believe that when the orbit of the Earth around the sun is just right, Antarctic icebergs begin to melt further and further away from Antarctica.