The Greenhouse Effect• The term Greenhouse effect has been derived from a phenomenon that occurs in a greenhouse.• Greenhouse effect is a naturally occurring phenomenon that is responsible for heating earth’s surface and atmosphere• One-fourth of the incoming solar radiation is absorbed by the atmospheric gases.• One-fourth of it is reflected by the clouds and gases• Only half of the incoming solar radiations falls on the earth and heats it and a small portion is reflected back.• Earth’s surface emits heat in the form of infrared radiations to the space, but most of it is absorbed by gases like carbon dioxide, nitrous oxide, chlorofluoro carbons and methane (greenhouse gases).• The molecules of these gases radiate heat energy that comes back to earth’s surface and heats it up.• The cycle is repeated till the long-wave radiations become unavailable for absorption.
How Greenhouse Effect works?
Greenhouse Gases• A greenhouse gas is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range.• Atmospheric concentrations of greenhouse gases are determined by the balance between sources (emissions of the gas from human activities and natural systems) and sinks (the removal of the gas from the atmosphere by conversion to a different chemical compound)• In order, the most abundant greenhouse gases in Earths atmosphere are: – Water vapor (H2O) – Carbon dioxide (CO2) – Methane (CH4) – Nitrous oxide (N2O) – Ozone (O3)
Causes of Greenhouse Effect
Deforestation• One of the man-made causes of the greenhouse effect is deforestation. Deforestation increases the amount of carbon dioxide in the atmosphere. Also, due to the disappearance of trees, photosynthesis cannot take place. Deforestation is rampant today due to the burden of our needs on land. The levels of deforestation have increased by about 9% in recent times. Also, the burning of wood causes it to decay, therefore releasing more carbon-dioxide into the atmosphere.
Burning of fossil fuels• Greenhouse gases can also be released into the atmosphere due to the burning of fossil fuels, oil, coal and gas. These materials are used increasingly and rampantly in industries. Most factories also produce many gases which last for a longer time in the atmosphere. These gases contribute to the greenhouse effect and also increase the global warming on the planet. These gases are not naturally available in the atmosphere. Therefore industries are also a major cause of the greenhouse effect.
Electrical Appliances• Other man-made causes of the increase in the greenhouse effect is the emission of greenhouse gases by electrical appliances. Even the humble refrigerator in the house emits gases which contribute to the greenhouse effect. These gases are known as Chlorofluorocarbons (CFCs) and are used in refrigerators, aerosol cans, some foaming agents in the packaging industry, fire extinguisher chemicals, and cleaners used in the electronic industry. Some processes of the cement manufacturing industries also act as a cause towards the greenhouse effect.
Population Growth• Population growth is an indirect contributor and one of the major causes of the greenhouse effect. With the increase in population, the needs and wants of people increase. This increases the manufacturing and the industry process. This results in the increase of the release of industrial gases which catalyze the greenhouse effect.
Relative Contribution of various greenhouse gases to global warming
Facts on Greenhouse Effect!! • Greenhouse effect is caused by greenhouse gases that trap the reflected heat from getting out of the atmosphere. • Some greenhouse effect is natural, and we need it for our survival. • The problem is that the greenhouse effect has increased way too much in the past 200 (particularly 40) years. • It has increased in tact with increasing greenhouse gases. • It is obvious that it is caused by humans because: • the unnaturally quick increase started when the western world started to be industrialized • we know that an industrialized world causes an increase in greenhouse gases - the main causes of the greenhouse effect • If the greenhouse effect did not exist, the Earth would be cooler by about 33˚C on average
What is Global Warming?Global warming is a gradual increase in the overall temperature of the earths atmosphere generally attributed to thegreenhouse effect caused by increased levels of carbon dioxide, CFCs, and other pollutants.
Graphs showing global average temperature
What is the Difference between global warming and climate change?• GLOBAL WARMING • CLIMATE CHANGE is is the increase of the a broader term that Earth’s average refers to long-term surface temperature changes in climate, due to a build-up of including average greenhouse gases in temperature and the atmosphere precipitation.
Portage Glacier Alaska1914 2004 Evidence Of Global warming
Colorado River-Arizona2002 2003
Causes of Global Warming• Increase in the level of greenhouse gases is mainly responsible for global warming• Release of methane gas from arctic tundra and wetlands is one of the natural cause of global warming.• Another natural cause is that the earth goes through a cycle of climate change• Overuse of the fossil fuels (Coal, Petroleum, Natural Gas) releases a large amount of CO2 in the atmosphere.• Deforestation is also one of the major causes of global warming as trees play a important role in curbing the CO2 level in the environment.
How is Global Warming Measured?Changes in the mean global temperature can be measured by:• Ground based weather records kept over a long time to track trends.• Sea water temperature records• Satellite imagery• Wildlife and plant life distribution• Sea ice records
Effects of Global Warming• An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, and a probable expansion of subtropical deserts.• Warming is expected to be strongest in the Arctic and would be associated with continuing retreat of glaciers, permafrost and sea ice• Other likely effects of the warming include more frequent occurrence of extreme-weather events including heat waves, droughts and heavy rainfall, species extinctions due to shifting temperature regimes, and changes in crop yields• Over the 21st century, climate change is likely to adversely affect hundreds of millions of people through increased coastal flooding, reductions in water supplies, increased malnutrition and increased health impacts• Warming above 3 °C could result in crop yields falling in temperate regions, leading to a reduction in global food production.• In small islands and mega deltas, inundation as a result of sea level rise is expected to threaten vital infrastructure and human settlements. This could lead to issues of statelessness for population from countries including the Maldives and Tuvalu.
The FutureOther effects could happen later this century, if warming continues.• Sea levels are expected to rise between 7 and 23 inches (18 and 59 centimeters) by the end of the century, and continued melting at the poles could add between 4 and 8inches (10 to 20 centimeters).• Hurricanes and other storms are likely to become stronger.• Species that depend on one another may become out of sync. For example, plants could bloom earlier than their pollinating insects become active.• Floods and droughts will become more common. Rainfall in Ethiopia, where droughts are already common, could decline by 10 percent over the next 50 years.• Less fresh water will be available. If the Quelccaya ice cap in Peru continues to melt at its current rate, it will be gone by 2100, leaving thousands of people who rely on it for drinking water and electricity without a source of either.• Some diseases will spread, such as malaria carried by mosquitoes.• Ecosystems will change—some species will move farther north or become more successful; others won’t be able to move and could become extinct. Wildlife research scientist Martyn Obbard has found that since the mid-1980s, with less ice on which to live and fish for food, polar bears have gotten considerably skinnier. Polar bear biologist Ian Stirling has found a similar pattern in Hudson Bay. He fears that if sea ice disappears, the polar bears will as well.
• Reduce the use of fossil fuels therefore reduce emission of greenhouse gases.• Improve energy efficiency• Reduce deforestation and plant more trees• Reduce the use of nitrogen fertilizers• Use Public Transport• Use Renewable Energy Like Wind Power• Burn methane• Use smart cooler, Heater & Air conditioners• Tune up and maintain vehicles properly• Clean the air in your house• Reduce electricity usage to the maximum• Prefer recycling.