Earth has gone through at least
five major ice ages in its history.
And you better start adapting now.
Because another ice age
is about to begin.
Hypothetically.
During all ice ages in Earth's history,
global temperatures
dropped well below
freezing across the planet.
And it wasn't just a few icy trips
around the Sun.
Earth can take
hundreds of millions of years
to thaw out.
The most recent ice age started
the Quartenary period
about 2.6 million years ago.
And technically, we’re still in it today.
Ice ages have
the power to radically change our planet.
They reshape landscapes.
They create new lakes and rivers.
Plants and animals cling to life,
either adapting or facing extinction.
So, if a new ice age began today,
how soon would our civilization collapse
into chilly chaos?
Our sixth major ice age
would be a few thousand years
in the making.
And it would begin with Earth’s
tilt on its axis
going through its cycle of changes.
An unstable
tilt plus a little wobble in our orbit
around the Sun,
and there would be less and less
solar radiation reaching the planet.
You’d see the first effects of this
on the Northern Hemisphere.
Each year, the once lovely
summer temperatures would start to drop.
Eventually, they’d fail
to rise above freezing.
And that’s when
snowfall would begin to build up.
Over time, that snow would compress
into ice sheets.
These glaciers would start in places
like the northernmost regions
of Canada, Scandinavia and Russia.
And they would spread from there.
The ice would mostly form on dry land.
That’s because the water surrounding
the ice would create a barrier
preventing it from expanding as easily.
Today, about 10% of Earth’s
land surface is covered by ice.
As our new ice age progresses,
you could see that go up to about 25%.
Ice would cover Eurasia
from the British Isles to Siberia.
Himalayan ice sheets would expand through Asia.
And while the Southern Hemisphere
wouldn’t be as icy,
an ice sheet would run from the southern
tip of Patagonia
well into the Andes Mountains.
But ice wouldn’t be the only change.
Sea levels could drop
around 120 m (394 ft)
lower than they are right now.
This could close off
the Mediterranean Sea
to the Atlantic Ocean.
Without anywhere else to go,
rainfall and glacial melting
would feed bodies of water in regions
that aren’t frozen over.
Some rivers would also change
their usual runoffs and form new lakes.
With all these changes
in sea levels around the world,
land bridges would re-emerge.
Russia would now be connected to Alaska,
and the islands of Indonesia would
connect to mainland Southeast Asia.
The borders would change
and bring many countries closer together.
Or it would result in whole new countries
being formed,
opening up new land
for you to migrate to.
And you’d need to.
Regions that you and hundreds
of millions of other people
used to call home
would now be essentially uninhabitable.
Surviving the cold
would mean moving away
from the iciest parts
of North America and Eurasia.
But the rest of the world wouldn't
be too welcoming either.
It would get really dry.
Deserts and tundras would expand,
so the remaining tropical forests
near the equator would be refuge
for much of the planet’s
plant and animal life.
But what about us?
Well, during the most recent ice age,
we actually developed as species.
The land bridges allowed us to spread out
across the globe.
And the climate forced us to adapt
with new tools and clothing.
And as Earth re-warmed,
we started farming.
It’s likely that we wouldn’t
fare as well with a new ice age.
Not right away, at least.
Almost all of our agricultural land
would be lost.
So intense overcrowding in hospitable
regions would create chaos and unrest.
You should get ready
for extreme competition
for life’s basic necessities.
But I do have good news
to ease your worries
about this frigid doomsday scenario.
"Come on, prove it!"
Well, sort of.
Based on current climate science
and the amount of carbon dioxide
in our atmosphere,
we may have postponed the next possible
ice age by about 500,000 years.
And if we keep pumping out
greenhouse gases,
it’s possible that we’ve
not only postponed it,
but we’ve made it impossible.
That just means we'll all overheat,
which I guess
is better than being frozen?
So Earth freezing over may
not need to be high on your worry list.
But maybe
all the world’s ice melting should.
Well, that’s a story for another WHAT IF.