CHAPTER – 41
GLOBAL WARMING
Beginning with the Industrial Revolution, we have relied on the energy stored in
the fossil fuels. As we burn the fossil fuels in the power plants, factories, and
cars, we release CO2 into the atmosphere. Since 1850, the CO2 content of the
atmosphere has increased from 280 parts per million to 370 ppm, or more than
30%, creating the highest CO2 concentration in more than 410,000 years. That
increase is continuing at the rate of 1.5 ppm yearly. Burning fossil fuels accounts
for 80-85% of the CO2 added to the atmosphere each year.
A second source of added atmospheric CO2, is deforestation which eliminates
tens of millions of forested acres annually. It accounts for 15-20% of CO2
emissions. Deforestations is principally occurring in the tropics, where
rainforests are rapidly being converted to marginal agricultural land. The carbon
stored in the massive trees in these forests returns to the atmosphere (primarily
through burning) after they are cut.
GREENHOUSE GASES TRAP HEAT IN THE ATMOSPHERE
Carbon dioxide represents only a tiny fraction of Earth’s atmosphere.
Atmospheric CO2 allows solar energy to enter, then absorbs and holds that
energy once it has been converted into heat. Several other greenhouse gases
share this property, including methane, chlorflurocarbons (CFCs), water vapor,
and nitrous oxide. The greenhouse effect, the ability of greenhouse gases to
trap the sun’s energy in a planet’s atmosphere as heat, is a natural process. By
keeping the atmosphere relatively warm, it allows life on Earth. There is
complete consensus among atmospheric scientists that human activities have
amplified the natural greenhouse effect, producing a phenomenon called global
warming.
Since the middle of the 19th century, human agriculture and industrialization
have dispensed an enormous quantity of these green house gases into the
atmosphere, where these have trapped enough heat to begin climate change.
According to the United Nations, there has been a rise of about 0.6 degrees
Celsius during the past century. More warming is expected to occur in the
coming decades
The main reasons for the emission of gases that are a cause of green house
effect are burning of fossil fuel like coal in the power plants for the purpose of
generation of electricity. Fossil fuel burning leads to high emissions of carbon
dioxide gas.
Another green house gas is methane. Methane is more than 20 times as
effectual as CO2 at entrapping heat in the atmosphere. Methane is obtained
from resources such as rice paddies, bovine flatulence, bacteria in bogs and
fossil fuel manufacture. Almost in all parts of the world, rice is grown on flooded
fields. When fields are flooded, anaerobic situation build up and the organic
matter in the soil decays, releasing methane to the atmosphere.
Nitrous oxide, which is a colorless gas with a sweet odor, is also a green house
gas. The main sources of nitrous oxide include nylon and nitric acid production,
cars with catalytic converters, the use of fertilizers in agriculture and the
burning of organic matter. A greater emission of nitrous oxides in the recent
decades is leading global warming.
Another jump in the category of green house gases is in the name of
hydroflourocarbons and perflourocarbons, man made chemicals initiated as a
substitute to other chemicals that deplete the atmosphere's protective ozone
layer.
In the last 100 years, average temperatures have risen about 10F. The 1980s
were the warmest decade on record, until their record was topped by the
1990s; thus far, 2001, 2002, and 2003 have been the three hottest years on
record.
Many factors, such as increases in cloud cover caused by increased evaporation,
possible increase in net primary productivity due to increased CO2, and the
uncertain capacity of the ocean to absorb CO2, make future climate prediction
difficult. The Intergovernmental Panel on Climate Change (IPCC), which consists
of hundreds of scientists throughout the world recently reported that “there is
new and stronger evidence that most of the warming observed over the last 50
years is attributable to human activities”. If greenhouse gases are not curtailed,
the IPCC predicts an increase of between 2.5 to 10.40F (1.4 to 5.80C) in average
world surface temperatures from 1990 to 2100, with temperature rising more
rapidly than in the past 10,000 years.
This rapid rise is of particular concern because it is likely to exceed the rate at
which natural selection can allow organisms to adapt. The temperature change
will not be distributed evenly worldwide; U.S. temperatures are predicted to
increase considerably faster than the global average.
CONSEQUENCES OF GLOBAL WARMING
Health
 One of the most serious effects of Global Warming that humans have to
think about are the effects on the health of individuals, nations and
therefore civilizations. The rise in temperature due to Global Warming is
known to be supportive to various viral diseases like the west nile virus
and malaria. This will result in economic as well as health effects on
human beings. For example, Global Warming will increase the incidence
of such diseases in poorer countries where these diseases exist. Global
Warming will also cause countries who have eradicated these diseases to
spend more on vaccinations and other ways of eradication like pesticides,
etc. The IPCC notes that global warming will increase the range of tropical
disease-carrying organisms, such as malaria-transmitting mosquitoes,
with negative consequences for human health.
 Global Warming results in a drastic rise in temperature. This rise in
temperature will finally result in an increase in the mortality rate of
people. A higher temperature causes problems to people with
cardiovascular problems. In extreme cases, people are known to have
died of heatstroke. People may also have heat exhaustion problems.
Respiratory problems are also known to arise out of a high temperature.
 High temperature also causes the concentration of ozone in the lower
atmosphere. Ozone is a harmful pollutant and causes respiratory
problems Ozone is also known to damage lung tissues and therefore
cause more complications for people with asthma. These are some of the
health effects of Global Warming.
 The glacier covering Mr. Everest has retreated three miles in the last 50
years.
 As polar ice caps and glaciers melt and ocean water expand in response to
atmospheric warming, seal levels will rise, threatening coastal cities and
flooding coastal wetlands.
 Global warming is also predicted to increase the intensity of hurricanes,
posing a further threat to coastal regions.
 Even small temperature changes can dramatically alter the paths of major
air and ocean currents, altering precipitation patterns in unpredictable
ways. Some land might become too hot and dry for agriculture, while
other areas might become warmer, wetter, and more productive.
Agriculture
 Overall, U.S. crop productivity might increase. As the world warms,
however, experts predict longer, more severe droughts and more
extremes in rainfall, leading to more frequent crop failure and flooding.
 Agricultural disruption could be disastrous for some nations that are
already barely able to feed themselves.
 The impact of global warming on forests could be profound. While overall
forest growth in the U.S. may increase, species distributions will change.
 Coral reefs, already stressed by human activities, are likely to suffer
further damage from warmer waters.

WHAT CAN WE DO TO REDUCE GLOBAL WARMING?
The total greenhouse gas emissions produced by the U.S amount to 6.6 tons per
person each year, more than any other country on Earth. With less than 5% of
the world’s population, the U.S. is responsible for more than 20% of world’s
greenhouse emissions.
 We can substantially reduce emissions of CO2 by using fuel-efficient
vehicles, carpools, and public transportation.
 As electricity is generated in fossil fuel fired power plants, so are
tremendous quantities of CO2, sulfur dioxide, and nitrogen oxides. We can
support the use of renewable energy such as wind and solar power.
 To conserve electricity, we can purchase more efficient appliances, turn
off unused computers and lights, and place incandescent lighting with
fluorescent light bulbs.
 Insulating and weatherproofing our homes, incorporating solar energy
features into new homes, and planting deciduous trees near our houses
to provide summer shade and winter sun will significantly reduce fuel
consumption while cutting back on heating and air conditioning
 Recycling is also tremendous energy saver.
 We can also support reforestation efforts to replace trees both in tropical
forests and in our communities.
 Although continued global warming is inevitable, its rate can be reduced
by human decisions.
 http://www.youtube.com/watch?v=oJAbATJCugs
GLOBAL WARMING