is a Greenhouse
lot of people think that the atmosphere is just air. But it is more complex
than that. It is actually a mixture of gases that surrounds the Earth,
performing many functions and helping to support life on our planet.
Earth is a huge greenhouse?
As you know, greenhouses use glass to keep the heat in. And just as the
glass in a greenhouse holds the sun’s warmth inside, so the atmosphere
traps the sun’s heat near the Earth’s surface. This keeps
the Earth warm using what are called “greenhouse gases”. Without
these gases, the sun’s heat would escape and the average temperature
of the Earth would drop from 15oC – 18oC!
gases and climate change
For thousands of years, the Earth’s atmosphere has changed very
little. The temperature and the careful balance of greenhouse gases have
stayed just right for humans, animals and plants to survive. But today
we are having problems keeping this balance. Because we burn fossil fuels
to heat our homes, run our cars, produce electricity, and manufacture
all sorts of products, we are adding more greenhouse gases to the atmosphere.
These activities are changing the atmosphere at a greater rate than humans
have ever experienced.
could happen if the climate changes?
By increasing the amount of “heat-trapping” gases, we are
adding to the warming effect of the natural atmospheric greenhouse. This
could warm the planet and have a huge effect on all forms of life. The
global sea level could rise due to several factors including melting ice
and glaciers. Rising sea levels could damage coastal regions through flooding
and erosion. The climate of various regions could change too quickly for
many plant and animal species to adjust. Harsh weather conditions, such
as heat waves and droughts, could also happen more often and more severely.
are the Greenhouse Gases?
Did you know that water vapor is the most common greenhouse gas? But there
are others that are very important too. Some occur naturally and some
come from human activity. Check out the list below.
Carbon Dioxide or CO2 is the most significant greenhouse gas released
by human activities, mostly through the burning of fossil fuels. It is
the main contributor to climate change.
Methane is produced when vegetation is burned, digested or rotted with
no oxygen present. Garbage dumps, rice paddies, and grazing cows and other
livestock release lots of methane.
You can find nitrous oxide naturally in the environment but human activities
are increasing the amounts. Nitrous oxide is released when chemical Fertilizers
and manure are used in agriculture.
Halocarbons are a family of chemicals that include chlorofluorocarbons
(which also damage the ozone layer), and other human-made chemicals that
contain chlorine and fluorine.
the Earth getting warmer?
Yes! Scientists may not agree exactly how much global warming will occur,
or exactly how much the climate will change, but they do agree that some
global warming has already occurred and there will likely be much more.
The 12 warmest years in the past 140 years have all been since 1980, with
eight of them since 1990. The Inter-governmental Panel on Climate Change
noted that 1990 was the warmest decade and 1998 was the warmest year.
what’s wrong with warmer temperatures?
For many in the temperate countries, warmer temperatures might not seem
like such a bad thing. But in tropical countries, this would be significant.
Scientists warn us of the possible consequences like:
more severe weather events like droughts, more powerful hurricanes, winter
storms and tornadoes
• flooding and erosion in the coastal regions
• our forests and farms would be at greater risk from pests, diseases
• damage to our water sources
change could also affect the health and well-being of people. Many larger
cities could experience a significant rise in the number of very hot days.
Air pollution problems would increase, placing children, the elderly and
people suffering from respiratory problems at greatest risk of health
effects. Increases in molds and pollens due to warmer temperatures could
also cause respiratory problems such as asthma for some people.
is being done around the world?
Climate change affects the entire globe. Developed and developing countries
are working together to find solutions to climate change. In June 1992,
the United Nations Framework Convention on Climate Change was signed by
154 countries that agreed to stabilize the amount of greenhouse gases
in the atmosphere at levels that won’t cause harm. In December 1997,
in Kyoto, Japan, 161 industrialized nations committed to reduce their
greenhouse gas emissions, as part of an international agreement on climate
change called the Kyoto Protocol.