Question

As recently at the 1970s, some scientists were saying an ice age was imminent. This seems to contradict the concern about global warming. Is an ice age coming, and, if so, will it counteract global warming?

Answer

Our global climate for the last two million years or so has typically had ice ages (glacial periods) lasting about 100,000 years. These are broken up by warm periods (interglacial periods) lasting between 10,000 and 30,000 years. This back-and-forth swing is basically caused by changes in the earth's orbit around the sun. We are about 10,000 years into an interglacial warm period, and in the next several thousand years, our planet will start to swing back into a glacial ice age. So we could say that in a geological time frame, a new ice age is "imminent."

Unfortunately, global warming is occurring at a much, much faster pace, and we can not rely on the still-distant next glacial period for relief of this potentially catastrophic problem.