IDIOT’S GUIDES: SCIENCE MYSTERIES EXPLAINED
What would happen if we desalinated the entire
All life on Earth depends on water, and all life on land depends on being able to drink
freshwater. But less than 1 percent of the Earth’s entire water supply is fresh and liquid.
We have the technology to desalinate seawater, so what would happen if we took all the
salt out of the ocean?
Desalinating the ocean even partially would be catastrophic for all sea life, which depends on the salt in the
water to survive. Life originally evolved in mineral-rich, salty water. Land-dwellers who depend on freshwa-
ter are the exception, not the rule ….
One of the great ironies of living on land is that you
need water to live … but most of the planet’s water is
undrinkable because of the salt and other mineral
content. Only 2 percent of the Earth’s water is salt-
free, and three quarters of that is locked up in the
polar ice caps.
That leaves just 0.5 percent of our total water in
liquid, drinkable form. The good news is, that still
represents many billions of gallons. The bad news
is that the global human population is now so huge,
real pressures are mounting on that water supply.
We do have the technology to desalinate
seawater. The process is surprisingly simple:
we pump water through a processing plant
that uses either membranes or dierences in
pressure to remove the salt and other minerals.
Saltwater goes in, freshwater comes out (and
the dry salt goes back in the ocean).
Today, we don’t have the technology to
desalinate the entire ocean and convert all the
planet’s water to fresh, but we certainly do have
the scientiﬁc knowledge to do it—it’s just a mat-
ter of building a lot of pumps. But changing the
salinity of the oceans could, ironically, kill us all.
Phytoplankton are the foundation of all
food webs on the planet, and these microscopic
plants also produce half of our oxygen. What’s
more, they’ve evolved to live in a very salty
ocean. The salt in the sea aects the way energy
and food can move in and out of their cells.
Single-celled phytoplankton feel this the most
strongly, but even large animals like ﬁsh are
sensitive to changes in salinity.
Sometimes the amount of salt in a particular part of the
ocean will drop, especially near the outﬂows of massive
rivers like the Amazon. If the salt level in seawater drops
too low, creatures in the area risk going into “osmotic
shock.” The chemistry of the water aects how water will
move in and out of their cells. Too little salt, and cells will
ﬁll up with water and even rupture. Phytoplankton can
literally explode if there’s not enough salt in the water.
Saltwater ﬁsh have evolved to absorb lots of water to
“ﬂush” salt from their bodies. In freshwater, they become
waterlogged, their internal membranes and organs are
damaged, and they die.
This is not to say we should stop using water desalina-
tion plants. In fact, desalination is probably essential to
the long-term survival of our civilization.
Throughout history, droughts and disruptions to fresh-
water supplies have emptied cities, destroyed nations, and
killed millions. Desalination can end our dependence on
fragile freshwater sources.
However, these desalination plants require quite a lot
of energy to run. This is usually supplied via electricity,
and critics of desalination say the system uses too much
power to be sustainable. But many desalination plants are
built in conjunction with wind farms or solar panel farms
to oset their electricity use.
Recent estimates suggest that converting to desalina-
tion plants away from freshwater dams would add only 10
percent to the electricity usage of a country like the Unit-
ed States. Split across the population, that’s about as much
power as running an extra refrigerator per person.
Distribution of Earth’s Water
Total Global Water
Total Global Freshwater
Saline ground water
Glaciers and ice caps
Swamps, rivers, soil,
air, plants, and animals
Ice and snow
IDIOT’S GUIDES: SCIENCE MYSTERIES EXPLAINED
What would happen if the ice caps completely
More than three quarters of the Earth’s freshwater is locked up in the ice caps. If all that
ice suddenly melted, the results would be catastrophic … but also unexpected.
The Antarctic ice would cause a huge rise in sea levels, but also massive earthquakes. And the melting of
Greenland’s ice could, strangely, freeze Europe ….
Climate change scientists have been warning the
world for some time now that one of the eects of
global warming will be a rise in sea levels. Cur-
rent models suggest melting glaciers and ice from
around the edge of the polar ice sheets could add as
much as 37 inches (94cm) to average sea level. That
could cause considerable damage in low-lying areas
and make many coastal cities more vulnerable to
storms and high tides.
If the whole of the northern ice sheet melted, it
wouldn’t make that much dierence to that ﬁgure.
That’s because there’s no land at the North Pole—
the ice is ﬂoating on water. And as we know, if we
let the ice in our drink melt, it doesn’t cause the
drink to overﬂow.
Antarctica is another matter entirely. The
southern ice sheet is much bigger—it’s 7,000
feet (2,133m) thick and contains 90 percent of
the world’s ice. It’s also sitting on top of an en-
tire continent. If that ice melts, it will add a bit
more than 37 inches (94cm) to the ocean. About
200 feet (60m) more.
Greenland has the next largest ice sheet,
enough to raise the oceans by a further 20 feet
(6m) should it melt entirely.
But there are other consequences of a mas-
sive melting event that go beyond sea level rise.
Antarctica is a very strange place geologi-
cally. The ice on the continent is so thick and
heavy, it’s pressed the surface of the Earth
inward, a little like a dent in a Ping-Pong ball.
If the ice melted and ﬂowed to the ocean, the
pressure on the land would be removed and
the crust would pop back out again. The whole
world could be wracked by massive earth-
quakes. There are also active volcanoes in
Antarctica that could erupt if seismic activity
If the ice caps are melting, that implies the ocean is
hotter overall. More heat in the ocean provides more en-
ergy for superstorms like hurricanes and cyclones. While
there might be fewer storms per season overall, the storms
that do form could be much more powerful than any we’ve
experienced so far. Typhoon Haiyan, which struck the
Philippines in 2013, may be just the ﬁrst of a new age of
It’s just one of the side eects that demonstrate how
complex the issues surrounding climate change really are.
It’s also why we use the term “climate change” rather than
“global warming”—yes, the whole system is getting hotter
overall, but local results might be the opposite, at least for
Ice has one more important role in our climate: its
shiny whiteness reﬂects a lot of sunlight. Reﬂectivity of a
planet is called its “albedo,” and if Earth maintains a high
albedo it stays colder as more sunlight is bounced o into
space. Less ice means lower albedo, which means more
sunlight absorbed, which means higher temperatures …
thus creating a “feedback loop.”
At this stage, it seems unlikely the ice sheets of Antarc-
tica or Greenland will melt in any time period shorter than
many thousands of years. Even so, over the next hundred
years the partial melting we’re already seeing will raise
sea levels and have damaging repercussions for our civ-
ilization. And also for the ecosystems that have adapted
to these huge expanses of ice at the top and bottom of our
The World if the Icecaps Melted
Current global water
Underwater if ice caps melt
New land formations after melt
IDIOT’S GUIDES: SCIENCE MYSTERIES EXPLAINED
Why does a hurricane have an eye, and why is it
The massive, spiral-shaped storms we know as hurricanes, cyclones, and typhoons are
among the most powerful forces on the planet. Yet in the middle of the strongest storms, a
circular region many miles across has blue skies and calm winds. Why?
For reasons not yet fully understood, when a hurricane gets powerful enough, air is forced down through
the center of the system, creating the calm eye. But this can be the most dangerous part of the storm ….
For all of our technological cleverness and dom-
inance of the biosphere, humans are still very
much at the mercy of nature’s most powerful
forces. Among these are hurricanes, cyclones, and
Despite decades of detailed study, the exact
reasons for why hurricanes form isn’t yet fully
understood. We do know that areas of low air
pressure—called depressions—can sometimes join
up and begin circling around a central point. As the
power of this system ramps up it creates a positive
feedback loop, making the storm stronger.
At some point in this process, a region in the
center called the “eye wall” becomes especially
powerful, with winds rotating faster than in the
rest of the storm.
While a hurricane resembles water spiral-
ing down a plug hole, it actually works in more
or less the opposite way: air is being sucked in
from the sides where pressure is higher, then
hurled into the upper atmosphere where it
spreads back out in a spiral pattern.
But, when the hurricane becomes powerful
enough, it starts sucking air down through the
center. Why this happens isn’t fully understood,
and there are hundreds of theories.
This downward force is enough to create a
region of incredibly low pressure, as much as 15
percent less than normal, and a circular area of
calm and blue skies.