Harneet+K.

TOPIC 5: Describe how climate be by human activities (eg. Greenhouse gasses, depletion of ozone layer)

//**"There is strong evidence that the war **////**ming of the Earth over the last half-century has been caused largely by human activity, such as the burning of fossil fuels and changes in land use, including agriculture and deforestation." **//
 *  The Royal Society 2010 **

Human Activities have been responsible for contributing to Climate Change since the beginning of the Industrial Revolution in the 19th century. The following are the major activities that contribute to Climate Change:

**Fossil Fuels ** Fossil Fuels release majorly carbon dioxide and nitrous oxide. The sources include industrial processes (4%), transportation (21%), use of chemical fertilizers (7%), and energy generation (65%) (According to the UK Government). Carbon dioxide and Nitrous oxide being greenhouse gases, cause global warming. The absorption of infrared radiations increases, causing and increase in temperature in the troposphere and decrease in temperature in the stratosphere. Changing temperatures can further cause an imbalance in the ecosystem leading to irregular rainfall patterns, intense and more frequent droughts, floods and hurricanes.


 * Patterns of Land Use **

· Agriculture: Methane (greenhouse gas) is released from the digestive tracts of animals (livestock) and decay of organic matter (in rice paddies and wetlands). It can also be released from leakage in gas pipelines, biogas plants and landfills. Methane is responsible for enhancing greenhouse effect. Several particles are also released in agriculture that can reflect sunlight, causing lower albedos. · Deforestation: Rainforests absorb 20% of the carbon dioxide emissions.The cutting down of rainforests has a disturbing effect on the carbon cycle, causing an extra 17% of greenhouse gases being released. Not only do the greenhouse gases cause even more global warming but also disturb the albedo. The deforested land gets prone to landslides, floods or becoming infertile(desertification).

Air pollutants such as sulfur dioxide and nitrogen oxides are known to have caused Acid Rain when they combine with water molecules in the atmosphere. They can be released from various sources including coal and oil burning, industrial and commercial processes, refining of gasoline from oil or extracting of metals from ores.  Particulate Matter refers to solid and liquid particles suspended in the air with a size smaller than 10 microns. Particulate Matter such as soot, dust, ammonium sulfate can either lead to a warming or cooling effect. Particulate matter containing “black carbon” has a warming effect on the atmosphere as it absorbs sunlight very effectively. They may deposit on snow or sea ice and reduce the sunlight reflecting ability, causing the snow to melt faster.
 * Pollution **

 Nuclear Wars can lead to the development of massive clouds of dust in the atmosphere that can block sunlight and lead to a “nuclear winter”. Also, black carbon particles released during wars can influence the climate for several months.
 * Wars **
 * “Iraq War Pollution Equals 25 Million Cars” **

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