by Stephanie Ho Lem, CHCA Director of Living Green
On my recent trip to Toronto, one of the hotel guests introduced an interesting topic, the Ice Age. “Yes, we will be looking ahead at an ice age. I don’t know when but it’s coming.” Well, the last time I heard those words was in high school, too many years ago to count. “What makes you think we’re heading into an ice age?”
He was visiting Toronto from “down under” and taking a break from work as a mining engineer, “there’s a lot of news around the world about the possibility of an ice age ahead.”
What do we know about the Ice Age, how often do ice ages happen, and when is the next freeze expected to begin?
Earth has undergone five big ice ages, some of which lasted for hundreds of millions of years.
There are many factors that cause an ice age. The main ones include variations in Earth’s orbit known as Milankovitch cycles. Scientist Milutin Milankovitch over a century ago, “hypothesized the long-term, collective effects of changes in Earth’s position relative to the Sun are a strong driver of Earth’s long-term climate and are responsible for triggering the beginning and end of glaciation periods (Ice Ages)”. When summer temperatures in the northern hemisphere fail to rise above freezing for years and winter snowfall doesn’t melt, but instead builds up, compresses, and over time starts to compact, or glaciate, into ice sheets, we are in an ice age.
During the last ice age, which finished about 12,000 years ago, enormous ice masses covered much of the land now inhabited by millions of people.
Since the 1800s, the amount of carbon dioxide (CO2) in the atmosphere has increased very quickly mainly by burning fossil fuels, which has then spurred warming. The source of this new carbon dioxide is not from natural sources like forest fires, volcanoes, or outgassing from the ocean. At the end of the last ice age, ecosystems had a good deal of time to adapt to the warming as it occurred. With increased CO2, warming is happening a lot faster. Many climate scientists agree that significant societal, economic, and ecological damage would result if the global average temperature rose by more than 2 °C (3.6 °F) in such a short time. At last count, global temperatures have reached 1.5 deg C.
Although scientists cannot say we have definitely prevented the next ice age, what is certain is that global warming is largely caused by human activities.
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Please note that the content provided is for informational purposes
Sources: ABC Science News, Live Science, Britannica, Climate Portal
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