If we condensed Earth’s 4.6-billion year history into one calendar year, humans evolved in the very last hour of December 31 – and the Industrial Revolution and modern age occurred the last two seconds of that year.
During those two short seconds we managed to affect Earth’s climate for tens of thousands of years. So much so that we essentially cancelled the next ice age, new research shows.
It means that we’ve not just altered today’s climate, but that we’re also changing the distant future of the Earth with potentially dire consequences. For the next 100,000 years, to be exact.
Why humans need another ice age
As humans, we usually have difficulty paying attention to anything that’s five or 10 years away – much less 50,000 or 100,000 years.
But those millennias matter. Without the last ice age, we wouldn’t have the beautiful landscapes, rivers and lakes found in our northern-most regions. Nor would we have the fertile soil that we rely on for agriculture.
Beyond aesthetics and food production, the major concern over a skipped ice age is that humans have now so profoundly altered the future of the Earth that we’re affecting the lives of thousands of generations ahead of us.
Andrey Ganopolski , the study’s lead author, called it “mind-boggling that humankind is able to interfere with a mechanism that shaped the world as we know it.”
How ice ages are usually formed
Ice ages often begin when there is less sunlight in the Northern Hemisphere during summer, causing less ice to melt and more ice to accumulate – which, in turn, causes more sunlight to be reflected, and so on.
These changes in sunlight depend on the shape of the Earth’s orbit around the sun, the angle of tilt of the Earth on its axis, and whether the tilt of the Earth is pointing toward or away from the sun – all of which vary on different timescales of tens of thousands of years.
When the conditions align in favor of a colder Northern Hemisphere summer, glaciers grow.
How we put the next ice age on hold
With the burning of fossil fuels over the last couple of centuries, however, we’ve added so much extra carbon dioxide to the atmosphere that the excess warming will outweigh the slight changes in sunlight that would have otherwise triggered the next ice age.
Humans have now so profoundly altered the future of the Earth, that we’re affecting the lives of thousands of generations ahead of us.
Although the next ice age isn’t due for another 50,000 years from now, a considerable amount of the carbon dioxide that we’ve emitted already, and will continue to emit, will still be in the atmosphere thousands of years from now.
The study published in Nature thus concludes it’s extremely unlikely that an ice age will form at all within the next 100,000 years.
Focus on today
It’s unclear what skipping an ice age will mean for our planet long-term. What we do know is that climate change is here and already causing irreversible damage.
But just like we have the power to interfere with an ice age, we can curb greenhouse gas emissions and gradually see them decline.
For the first time, there’s now a global consensus that action must be taken to limit the worst of climate change.
That’s where our focus is, and should be, today.
This story has been republished with permission from the Environmental Defense Fund.