Grand Solar Minimum.... And Cooling.... Something that really struck me the other Day when posting Greenland Ice Cores was the rapid fall into cooling that happens cyclically every 1.2 thousand years. And each event is preceded by a warming trend spike just before a rapid decrease in global temperatures. Temperatures spiked and rise ended in 1998, according to balloon data sets used to certify satellite measurements. Our current spike will look like many others in the Holocene very soon as Grand Solar minimum happens every 1,200 years. Each of the cooling events following there warming spikes has resulted in a 0.5 deg C drop in temperature before then forming a new cooler base line.