A Cooling


In the early 1970s, a different kind

of climate worry took hold:

global cooling.

As more people became concerned about pollutants people were emitting into the atmosphere, some scientists theorized the pollution could block sunlight and cool

ice age?

In fact, Earth did cool somewhat between

1940-1970 due to a postwar boom in aerosol

pollutants which reflected sunlight away

from the planet.

The idea that sunlight-blocking pollutants could chill Earth caught on in the media, as in a 1974 Time magazine article titled “Another Ice Age?”

But as the brief cooling period ended

and temperatures resumed their

upward climb, warnings by a minority

of scientists that Earth was cooling

were dropped.

Part of the reasoning was that while smog could remain suspended in the air for weeks, CO2 could persist in the atmosphere for centuries.

CFC and


Scientists explore and discover more as they widen their scope on the cause of our planet heating up. As it turns out, chlorofluorocarbons (CFC) are in widespread use up until this time and is slowly killing our protective blanket that is the Ozone Layer.

People started to believe

that this was an issue worth

noting. Since the late 1970s,

the use of CFCs has been

heavily regulated because

of their destructive effects

on the ozone layer.


The very first Earth Day was on April 22, 1970. About 20 million people attended the event.

26 August 1987



By 1987, in response to a dramatic seasonal

depletion of the ozone layer over Antarctica,

diplomats in Montreal forged a treaty,

the Montreal Protocol, which called

for drastic reductions in the production

of CFCs.

On March 2,1989, twelve European Community nations agreed to ban the production of all CFCs by the end of the century. The image shows the CFC concentration in 1979 versus 2008.

In 1990, diplomats met in London and voted to significantly strengthen the Montreal Protocol by calling for a complete elimination of CFCs by the year 2000.

By the year 2010, CFCs should have been completely eliminated from developing countries as well.