Climate Change, Elective Geography, Enhanced Greenhouse Effect, News, Upper Secondary Geography, Weather

Living in a Greenhouse: A thickening blanket around the Earth

March 9, 2017 theserangoonview 2 Comments

A thick blanket of smoke obscures the land as methane fires rage in a US garbage landfill

What is the greenhouse effect?

A layer of greenhouse gases – primarily water vapour, and including much smaller amounts of carbon dioxide, methane and nitrous oxide – acts as a thermal blanket for the Earth, absorbing heat and warming the surface to a life-supporting average of 15 degrees Celsius.

An overview of the Greenhouse Effect. From IPPC Working Group 1 contribution, Science of Climate Change, Second Assessment Report 1996

Essentially this process slows the loss of heat to space, keeping the earth’s surface warmer than it would be without the greenhouse gases. Without this “greenhouse” the Earth’s atmosphere would be an average of about 30-35 ^oC cooler and life as we know it would not exist.

Then what is the enhanced greenhouse effect?

The enhanced greenhouse effect, sometimes referred to as climate change or global warming, is the impact on the climate from the additional heat retained due to the increased amounts of carbon dioxide and other greenhouse gases (GHGs) that humans have released into the earth’s atmosphere since the industrial revolution.

Black smoke from burning of associated gas, releasing Nitrous Oxide into the atmosphere.

On Earth, human activities are changing the natural greenhouse. Over the last century, the burning of fossil fuels like coal and oil has increased the concentration of atmospheric carbon dioxide (CO₂). This happens because the coal or oil burning process combines carbon with oxygen in the air to make CO₂. To a lesser extent, the clearing of land for agriculture, industry, and other human activities has increased concentrations of greenhouse gases.

An aerial view of Amazon rainforest burning to clear land for cattle pasture near the city of Novo Progresso, Para state, September 23, 2013. Picture taken on September 23, 2013. REUTERS/Nacho Doce (BRAZIL)

Anthropogenic factors (Human activities) which lead to the enhanced greenhouse effect:

Burning of fossil fuels
Deforestation
Changing land use (Rice cultivation, cattle ranching, etc)
Industrialisation
Urbanisation

Global atmospheric concentrations of four greenhouse gases. From the IPCC 2007 4th Assessment Report

Gases that contribute to the greenhouse effect include:

Water vapour

The most abundant greenhouse gas, water vapour increases as the Earth’s atmosphere warms, but so does the possibility of clouds and precipitation.

This photo shows a heavily logged concession affiliated with Asia Pulp and Paper, or APP, one of the world’s largest papermakers, on the Indonesian island of Sumatra, in 2010.

Carbon dioxide (CO₂)

Carbon dioxide is released through both natural processes such as respiration and volcano eruptions and through human activities such as deforestation, land use changes, and burning fossil fuels.
Carbon oxidation is a process by which carbon in the soil reacts with oxygen in the atmosphere to produce CO². Deforestation exposes soil to sunlight which increases the soil temperature.
Humans have thus increased atmospheric CO₂ concentration by more than a third since the Industrial Revolution began.
To find out about deforestation in the Amazon Rainforest, go here: https://theserangoonview.wordpress.com/2017/02/28/why-is-the-amazon-rainforest-important/

Methane

A hydrocarbon gas produced both through natural sources and human activities, including the decomposition of wastes in landfills, agriculture, and especially rice cultivation.
Methane is released when dead leaves and manure decompose rapidly in the rice field due to a high level of moisture in the soil.
Greenhouse gas emissions associated with livestock supply chains (e.g. Cattle farming) account for 14.5% of all human-caused GHG releases, according to a report published by the UN Food and Agriculture Organisation in 2013.
With increased prosperity, people are consuming more meat and dairy products every year, global meat production is projected to more than double from 2001 to 2050.

Nitrous oxide

A powerful greenhouse gas produced by soil cultivation practices, especially the use of commercial and organic fertilisers, fossil fuel combustion, nitric acid production, and biomass burning.
The use of chemical fertilisers increases the amount of nitrous oxide in soil. The nitrous oxide is then released when soil is ploughed or when rain flows through the soil.
More fossil fuels are burnt to produce energy for household activities in urban areas such as heating, cooking and lighting.
More cars, buses and other transportation on the roads also increase greenhouse gas emissions.
Constructing infrastructure and producing construction materials also release Nitrous Oxide into the atmosphere.

A farmer sprays a chemical fertiliser containing nitrogen on a wheat field in southern France. Nitrogen fertilisers are a known source of greenhouse gases.

Chlorofluorocarbons (CFCs)

Synthetic compounds entirely of industrial origin used in a number of applications, but now largely regulated in production and release to the atmosphere by international agreement for their ability to contribute to the destruction of the ozone layer.
To see how the ozone layer protects us, go here: http://earth.rice.edu/mtpe/atmo/atmosphere/topics/ozone/o3.html
For a more detailed explanation of protective ozone, go here: https://disc.gsfc.nasa.gov/ozone/additional/science-focus/about-ozone/ozone_atmosphere.shtml