During the last few decades, average global temperatures and sea levels have risen and the ferocity of major storms and forest fires have increased. These changes deviate from climate trends over the last millenium or longer.
Glaciation in the Northern Hemisphere during the Wisconsin Ice Age about 20,000 years ago. Turquoise shading indicates the extent of the ice sheet about 3 km thick.
Bloom (2010) Global Climate Change: Convergence of Disciplines. Sinauer Associates.