The villain in the atmosphere

The Villain In The Atmosphere

Isaac Asimov

The villain in the atmosphere is carbon dioxide.

It does not seem to be a villain. It is not very poisonous and it is present in the atmosphere in

so small a quantity that it does us no harm. For every 1,000,000 cubic feet of air there are only 340

cubic feet of carbon dioxide--only 0.034 percent.

What

’

s more,that small quantity of carbon dioxide in the air is essential to life. Plants absorb

carbon dioxide and convert it into their own tissues,which serve as the basic food supply for all of

animal life (including human beings,of course). In the process,they liberate oxygen,which is also

necessary for all animal life.

But here is what this apparently harmless and certainly essential gas is doing to us:

The sea level is rising very slowly from year to year. The high tides tend to be progressively

higher,even in quiet weather, and storms batter at breakwaters more and more effectively,erode the

beaches more savagely,batter houses farther inland.

In all likelihood,the sea level will continue to rise and do so at greater rate in the course of

next

hundred

years.

This

means

that

the

line

separating

ocean

from

land

will

retreat

inland

everywhere.

It

will

do

so

only

slightly

where

high

land

abuts

the

ocean.

In

those

places,however,where there are low- lying coastal areas(where a large fraction of humanity lives)

the water will advance steadily and inexorably and people will have to retreat inland.

Virtually all of Long Island will become part of the shallow offshore sea bottom,leaving only

a line of small islands running east to west,marking off what had been the island

’

s highest points.

Eventually the sea will reach a maximum of two hundred feet above the present water level,and

will

be

splashing

against

the

windows

along

the

twentieth

floors

of

Manhattan

’

s

skyscrapers.

Naturally the Manhattan streets will be deep under water, as will the New Jersey shoreline and all

of Delaware. Florida,too,will be gone,as will much of the British lows,the northwestern European

coast,the crowded Nile Valley. And the low-lying areas of China,India,and the Soviet Union.

It is not only that people will be forced to retreat by the millions and that many cities will be

drowned,but much of the most productive farming areas of the world will be lost. Although the

change will not be overnight,and though people will have time to leave and carry with them such

of their belongings as they can,there will not be room in the continental interiors for all of them.

As the food supply plummets with the ruin of farming areas,starvation will be rampant and the

structure of society may collapse under the unbearable pressures.

And all because of carbon dioxide. But how does that come about? What is the connection?

It begin with sunlight,to which the various gases of the atmosphere(including carbon dioxide)

are

transparent.

Sunlight,striking

the

top

of

the

atmosphere,

travels

right

through

miles

of

it

to

reach the Earth

’

s surface, where it is absorbed. In this way the Earth is warmed.

The Earth

’

s surface doesn

’

t get too hot,because at night the Earth

’

s heat radiates into space in

the form of infrared radiation. As the Earth gains heat by day and loses it by night, it maintains an

overall temperature to which Earthly life is well-adapted.

However,the atmosphere is not quite as transparent to infrared radiation as it is to visible light.

Carbon dioxide in particular tends to be opaque to that radiation. Less heat is lost at night,for that

reason, than would be lost if carbon dioxide were not present in the atmosphere. Without the small

quantity

of

that

gas

present,

the

Earth

would

be

distinctly

cooler

on

the

whole,perhaps

a

bit

uncomfortably cool.