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Global climate change by global warming

March 17, 2016 | Author: | Posted in ecology, nature

Global Climate Change by Global Warming

Global Warming

Global warming refers to increasing temperatures and consequent climate changes worldwide . Scientists believe the earth may be warming up because heat-trapping gases are building up in the atmosphere disturbing a natural process that maintains the world ‘s climates . This process , called the greenhouse effect , works just as its name suggests Gases naturally present in the earth ‘s lower atmosphere act like the glass in a greenhouse , allowing the sun ‘s radiation in and trapping the heat that would otherwise escape back into space [banner_entry_middle]

. This natural balancing act between incoming and outgoing radiation keeps the earth from either icing up or overheating . Now human activities are upsetting the balance by dumping heat-trapping gases into the air . Excess carbon dioxide chlorofluorocarbons , nitrous oxide , methane and possibly ozone appear to be causing a gradual increase in global temperatures (Arrhenius 1997

The Human Factor

Carbon dioxide is a natural greenhouse gas , a plentiful by-product of respiration and plant decay . But carbon dioxide is also given off when we burn fossil fuels to power our cars and heat our homes . Burning forests to make farmland adds still more carbon dioxide–from the fire itself , and from the loss of trees and vegetation that would otherwise be removing carbon dioxide from the air . In the last century , these human activities have caused a 25 percent increase in carbon dioxide concentrations in the air worldwide . If current trends continue scientists predict that the amount of carbon dioxide will double by the year 2050 , leading to an overall warming of between 1 .5 and 4 .5 degrees centigrade . That could be enough to melt polar icecaps , flooding the world ‘s coastal areas . Warming would affect global rainfall patterns and cause major shifts in desert and fertile regions (Andreae 1996

Carbon dioxide , however , is not the only natural greenhouse gas whose concentrations are increasing because of human activities . Methane ozone and nitrous oxides are also building up above natural levels Methane gas is emitted during such activities as rice cultivation and animal husbandry . Methane is also a by-product of landfills , coal seams natural gas exploration and the burning associated with deforestation Nitrous oxides found only occasionally in nature are being added in vast quantities to the earth ‘s atmosphere as we burn fossil fuels . Ozone whose importance as a worldwide greenhouse gas is still being debated is created when sunlight shines through air polluted with auto and industrial emissions

Chlorofluorocarbons (CFCs ) are the only greenhouse gases that are not found in nature . First manufactured in the 1930s , this group of chemicals has been widely used since in refrigerators and air conditioners and as propellants in aerosol cans (the U .S . banned CFC use in aerosol cans in 1978 . Although less plentiful in the air than the other greenhouse gases , CFCs are 25 ,000 times more efficient at trapping heat and are so stable that they can stay in the air for up to 100 years (Anderson et al 2003

The Common Threads

Some of the same gases that contribute to global warming are also named in discussion of another atmospheric condition we hear-much about these days–the ozone hole . Ozone gas in the upper atmosphere absorbs the sun ‘s ultraviolet rays , acting as a shield that prevents much harmful radiation from reaching earth (This high-altitude version of ozone occurs naturally and is not to be confused with the ground-level ozone pollution that may play a role in global warming

A few years ago , scientists first detected a seasonal thinning in the upper atmosphere ozone above Antarctica . Since then , concern has also arisen that conditions exist for a similar springtime hole to form over the North Pole . Without the protective ozone shield , living things are exposed to increased amounts of ultraviolet radiation . This radiation can cause human skin cancer and eye diss , and might also reduce yields of phytoplankton and some agricultural crops (Agrawala 1999

What causes the ozone hole ? The same synthetic chemicals that bear part of the responsibility for global warming–chlorofluorocarbons . The long-lived CFCs we use ultimately drift up 10 miles or more into the stratosphere . Here , they are bombarded by fiercely energetic ultraviolet radiation from the sun and finally break down , releasing very reactive chlorine atoms which , in their turn , break apart ozone . As the ozone thins , we lose our protective shield . Both for increases in global temperatures and for the ozone hole , the scientific evidence is building while the potential impacts are not yet fully understood . But the seriousness of the two problems and the role of man-made CFCs in both of them have not gone unnoticed by the world ‘s governments . More than 90 nations recently joined forces to control ozone depletion , agreeing to phase out CFCs by the end of the century . In New York State , Gov . Mario Cuomo signed legislation that restricts the use of CFCs in refrigerators , automobile air conditioners and fire extinguishers (Anderson 2003

Many scientists agree that global warming–the artificial heating of the atmosphere–is beginning to change the world ‘s climate

The National Aeronautics and Space Administration (NASA ) reports that the average temperature on Earth ‘s surface has risen by one degree in the past 100 years . The 10 warmest years of the 20th century occurred in the last 15 years–and 1998 was the warmest year on record

Many scientists believe that unless people make efforts to reduce global warming , we may face harmful consequences . In addition to warmer temperatures , the ocean ‘s sea level has risen between 4 and 10 inches in the past century . And the polar ice caps have been thinning at both the North and South poles (Agrawala 1999

Environmental Threat

What causes global warming ? Scientists explain that gases trapped in the atmosphere create a “greenhouse effect ” These gases protect life on Earth much as a greenhouse protects plants in winter

Some of the greenhouse effect is normal . Water vapor , carbon dioxide and other gases trapped in the atmosphere help keep Earth warm enough to sustain life

What worries experts is that Earth ‘s temperature is rising abnormally–all because of a big increase in the amount of certain gases in the atmosphere

Large amounts of carbon dioxide enter the atmosphere when fossil fuels such as oil and coal are burned . Because we are burning more and more fossil fuels , the amount of carbon dioxide in the air has been rising steadily . It is now 30 percent higher than it was when the Industrial Revolution began 200 years ago

Cars and power plants are the leading sources of this added carbon dioxide . That means that every time you use the family car , run the dishwasher , or turn on the TV , more carbon dioxide is released into the air

The United Nations , in a report dated October 26 , said that if we stay on our current course , the average global temperature is likely to rise from 2 .7 to 11 degrees in the next century . That may not sound like much , but during the last ice age , the average temperature was only 9 degrees cooler than today . Hundreds of the world ‘s most respected climate scientists worked to develop this report . They said that humans have contributed substantially to global warming (Baer 1991

Is Global Warming a Myth

Not everyone agrees that global warming is real–or that an increase in carbon dioxide and other gases in the atmosphere causes global warming

Recently , a group of scientists suggested that a possible cause of Earth ‘s warmer temperatures could be an increase in the sun ‘s heat Other scientists blame warmer temperatures on natural fluctuations in Earth ‘s weather patterns (Bord et al 1998

Is Global Warning a Fact

But a majority of scientists believe that global warming is a serious problem . How serious ? What you one say about global warming is that it is enough to affect the probability [chances] of having a warmer-than-normal season . But it is not enough to make every season warmer than it used to be 50 years ago (Bord et al 1998

What Has Been Done

In 1997 , delegates from 160 nations met in Kyoto , Japan , to work out a treaty to reduce global warming . The treaty set specific targets for reducing greenhouse-gas emissions . To meet the treaty ‘s goals , the U .S and many other countries would have to reduce their use of fossil fuels .These countries would have to spend large amounts of money to develop new technology to meet those goals . So far , only eight countries have ratified the treaty . The U .S . is not one of them

If global warming is not a real problem , then these countries would have spent money for nothing . However , if global warming is really happening then there is no time to waste in taking action

There are a lot of actions you could take that make sense . It is said that building more fuel-efficient cars would reduce pollution , lessen health problems , and reduce U .S . dependence on foreign oil . In effect these steps do not cost anything . In many ways , they are economically beneficial . Instead , more and more Americans are buying sport-utility vehicles (SUVs . These light trucks emit up to five times the amount of pollutants as cars (Bord et al 1998

What People Can Do

Can individuals do anything to cut down on global warming ? There are many things that one can do–from lowering the temperature at home in winter to walking instead of driving . The Environmental Protection Agency (EPA ) recommends the following steps

When families buy new appliances , they should look for the Energy Star (TM ) label . According to the EPA , a high-efficiency refrigerator alone can reduce carbon dioxide emissions by as much as 220 pounds a year

Compact fluorescent light bulbs save up to 40 percent more energy than regular light bulbs

A properly insulated home is a big step toward wasting less energy . It can reduce carbon dioxide emissions by more than 2 ,000 pounds a year

Recycling , and buying products that use recycled packaging , could help one ‘s family reduce carbon dioxide emissions by more than 1 ,000 pounds annually

One of the biggest causes of pollution is the family car . Anything one can do to cut down on unnecessary car trips will help cut down on global warming (Bostrom et al 1994

References

Agrawala , Shardul . 1999 “Early Science-Policy Interactions in Global Climate Change : Lessons from the Advisory Group on Greenhouse Gases Global Environmental Change 9 (2 : 157-69

Anderson , Theodore L , et al . 2003 “Climate Forcing by Aerosols — a Hazy Picture ” Science 300 : 1103-04

Andreae , Meinrat O . 1996 “Raising Dust in the Greenhouse ” Nature 380 389-90

Arrhenius , Gustaf . 1997 “Carbon Dioxide Warming of the Early Earth Ambio 26 : 12-16

Baer , F , et al , Eds . 1991 . Climate in Human Perspective : A Tribute to Helmut F . Landsberg . Dordrecht : Kluwer Academic

Bord , Richard J , et al . 1998 “Public Perceptions of Global Warming United States and International Perspectives ” Climate Research 11 75-84

Bostrom , Ann , et al . 1994 “What Do People Know About Climate Change ? 1 Mental Models ” Risk Analysis 14 : 959-70

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