Description:
Clouds cover about 70% of the planet at any moment. But what if — poof —
they all disappeared? While hurricane season would be over essentially forever,
we'd have huge problems on our hands, like a dwindling supply of fresh water
and a much, much hotter planet.
Transcription:
From thin and wispy to big and puffy, clouds cover about 70% of the planet
at any given moment. But what if, in the next minute, poof, they all disappeared?
That instant might shock onlooking astronauts on the space station. But someone
who is, say, hiking in the desert wouldn't know right away that things on Earth
were about to get really bad. Within a few days, though, the first warning sign
would show up: humidity. It'll be even worse if you live by the coast. Normally,
the sun's heat evaporates water, mostly from the ocean, and that water vapor
is condensed into clouds. But if clouds are cut out of the Earth's water cycle,
that water just hangs around in the air, creating close to 100% humidity.
If you were to get on a flight, you might experience more turbulence than usual.
Without the protective cover of clouds to bounce sunlight into space, the sun
will heat the Earth more, creating more rising, uneven hot air. But a bad flight
may be the least of our worries, because there'll be no more rain or snow
or even a light mist, and that means there won't be any way to replenish the
water sources we drink from, like lakes, streams, rivers, springs, and aquifers.
So once last winter's snow melts, we're stuck with whatever water we have
on hand. And the clock is ticking. If the world were to keep up its current
water-consumption rate, we would drain all of the freshwater lakes and rivers
in about 23 years. So to conserve our freshwater supply, humanity will have
to be strategic. Today, the average American uses about 80 to 100 gallons
of water every day. But saving ourselves is going to take more than just skipping
long showers and laundry. The water we use in our home and public places
accounts for only 21% of our water usage. The two biggest demands are
actually thermoelectric power to generate electricity and irrigation for farms.
Not only do power plants use tons of water, ones that run on nuclear fuel
could spell disaster if their water-cooling towers run dry. The 2011 Fukushima
nuclear disaster, for example, was set off when an earthquake knocked out
power to its water-cooling pumps. And farms are going to need even more
water without the help of a good rain. This permanent drought would kill tons
of wild vegetation and animals as the land dries up Within a few years, eroding
soil may kick up giant dust storms like the Dust Bowl in the 1930s. Meanwhile,
Earth's climate will be going haywire without clouds. It's hard to say when this
will all happen without some very expensive climate modeling, but cloud expert
Chris Fairall did offer some quick back-of-the-envelope calculations. Without
clouds, average surface temperatures would rise by as much as 22 degrees
Celsius. This extreme temperature spike would not only destroy the habitats
of most flora and fauna, killing off whatever survived the drought, it would also
melt the polar ice caps and cause massive flooding of coastal cities.
You might end up being part of the 40% of the world that would be forced
inland, and your new home might soon be in an endless desert as seawater
starts seeping into our fresh and precious groundwater. Sounds alarming,
but there are some silver linings to a world without clouds. No more devastating
hurricanes and tornadoes, or delayed flights because of stormy weather,
or cloudy skies to ruin your stargazing. As the water supply dwindles, we'll have
to make some hard choices, but, hey, humans are creative. We could invent
ways to desalinate ocean water or collect all that water vapor from the air.
And the sooner we do it, the better, because in reality, we're already losing
clouds. Unprecedented levels of CO2 and the warming oceans and atmosphere
are all causing clouds to thin out. So despite the silver linings, it might be best
to reduce our greenhouse gas emissions
Questions:
1. How many percent does clouds cover the planet?
2. How are clouds form?
3. Talk about the importance of the clouds.
What would happen when clouds disappear?