During global cooling periods, there is less ocean evaporation, fewer clouds, lower albedo, which allows more TSI to hit the earth's surface, thus preventing snowball earth. (wattsupwiththat.com)
But the results of studying earth climate in the past, indicates we currently in an unusual cool period, and that human evolution coincided with global cooling period. (judithcurry.com)
The book proves that four months of activities at sea in autumn 1939 had been sufficient to generate the coldest winter in Europe since the Little Ice Age and that six years of global naval war were enough to contribute to the only global cooling period since the world got warmer since about 1850, which lasted from 1940 to the 1970th. (1ocean-1climate.com)