Many climate scientists, such as Fred Singer, now a well-known contrarian, called for action to halt the cooling. US government advisers proposed putting giant mirrors into orbit to direct more sunlight onto Earth. Others suggested sprinkling Himalayan glaciers with soot to absorb heat and maintain the ice-melt that feeds the region's rivers. What prompted this panic? Three decades of evident, if mild, cooling had set the scene, but there was also genuine concern among climate scientists based on predictions of both natural and human-made climate change.