Was the last ice age caused by global warming?

Answer 1

The last ice age is believed to have been triggered by the Milankovich cycles, which operate over the very long term and have great value as a theory to explain ice ages and long-term changes in the climate. Milankovich cycles can cause a very small reduction in average global temperatures over a period of centuries, but are considered too weak to be the only explanation of the ice ages. Scientists say that as the earth cooled slightly, as a result of a change in the Milankovich cycle, the level of atmospheric water vapour fell, resulting in a gradual further fall in temperatures. Eventually, carbon dioxide concentrations began to fall in tandem with falling water vapour levles, until an ice age was underway.

After a period of thousands of years, the cycle was self-correcting. Ice covered much of the seas, while the remainder of the ocean was too cold to absorb much carbon dioxide. Rising carbon dioxide levels began to warm the world once again, leading to higher water vapour levels and eventually a return to normal temperatures.

Milankovich cycles are considered unimportant for short term climate changes such as the present period of global warming.