The Science of Living in a Greenhouse
1) What is the Greenhouse Effect?
We live in a greenhouse. Life on Earth depends on energy coming from the sun. About half the light reaching Earth's atmosphere passes through the air and clouds to the surface, where it is absorbed and then radiated upward in the form of infrared heat. About 90 percent of this heat is then absorbed by the greenhouse gases and radiated back toward the surface, which is warmed to a life-supporting average of 15 degrees Celsius.
We live in a greenhouse. Life on Earth depends on energy coming from the sun. About half the light reaching Earth's atmosphere passes through the air and clouds to the surface, where it is absorbed and then radiated upward in the form of infrared heat. About 90 percent of this heat is then absorbed by the greenhouse gases and radiated back toward the surface, which is warmed to a life-supporting average of 15 degrees Celsius.
2) Practical: Observing the Greenhouse Effect
3) What are the "Greenhouse Gases"?
Certain gases in the atmosphere block heat from escaping. Gases that contribute to the greenhouse effect include:
Certain gases in the atmosphere block heat from escaping. Gases that contribute to the greenhouse effect include:
- Water vapor. This is the most abundant greenhouse gas. Extension - But more importantly, it acts as a feedback to the climate. This means that water vapor increases as the Earth's atmosphere warms, but so does the possibility of clouds and precipitation, making these some of the most important feedback mechanisms to the greenhouse effect.
- Carbon dioxide (CO2). A minor but very important component of the atmosphere, carbon dioxide is released through natural processes such as respiration and volcano eruptions and through human activities such as deforestation, land use changes, and burning fossil fuels. Humans have increased atmospheric CO2 concentration by a third since the Industrial Revolution began. This is the most important long-lived "forcing" of climate change.
- Methane. A hydrocarbon gas produced both through natural sources and human activities, including the decomposition of wastes in landfills, agriculture, and especially rice cultivation, as well as produced by domestic livestock such as cattle. On a molecule-for-molecule basis, methane is a far more active greenhouse gas than carbon dioxide, but also one which is much less abundant in the atmosphere.
- Nitrous oxide(N2O). A powerful greenhouse gas produced by soil cultivation practices, especially the use of commercial and organic fertilizers, fossil fuel combustion, nitric acid production, and biomass burning.
- Chlorofluorocarbons (CFCs). Synthetic compounds of 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 destruction of the ozone layer. They are also greenhouse gases.
4) Quiz on Greenhouse Effect
1. Suggest why Earth’s atmosphere has been described as a giant invisible blanket.
2. What is:
a) the greenhouse effect?
b) The enhanced greenhouse effect?
c) Global warming
3. Suggest four consequences of global warming.
4. Give examples of three types of greenhouse gases and at least two sources of each one.
5) The Impacts of Climate Change.
Use the Australian Museum website to describe the following predicted impacts of climate change. a) Increased Air Temperature b) Increased Ocean Temperature c) Increased Acidity of the Oceans d) Impact on ecosystems and species e) Change in Sea Levels |
The Following Statement is from the Australian Government Department of Environment website.
"Our climate is changing, largely due to the observed increases in human activities such as the burning of fossil fuels (coal, oil, and natural gas), agriculture and land clearing. Changes over the 20th century include increases in global average air and ocean temperature, widespread melting of snow and ice and rising global sea levels. The extra heat in the climate system has other impacts such as affecting atmospheric and ocean circulation, which influences rainfall and wind patterns.
Another serious impact of the increasing concentration of atmospheric carbon dioxide is ocean acidification. Around a quarter of the carbon dioxide produced by humans is absorbed by the oceans. As the carbon dioxide dissolves in sea water it forms a weak carbonic acid, making the ocean more acidic. There are early indications that some marine organisms are already being affected by ocean acidification.
The global average air temperature has increased by around 0.85 degrees Celsius since 1880.[i] The observed increase in temperatures has occurred across the globe, with rising temperatures recorded on all continents and in the oceans. World Meteorological Organization records show that the decade of 2001-10 was the world’s warmest decade on record, and that the 2000s were warmer than the 1990s which in turn were warmer than the 1980s. In Australia, average air temperatures have increased by around 0.9 degrees Celsius since 1910, and each decade has been warmer than the previous decade since the 1950s.[ii]
Scientists agree that the worst effects of climate change can largely be avoided if carbon dioxide emissions are reduced to an acceptable level."
So let's understand fossil fuels and their combustion........
"Our climate is changing, largely due to the observed increases in human activities such as the burning of fossil fuels (coal, oil, and natural gas), agriculture and land clearing. Changes over the 20th century include increases in global average air and ocean temperature, widespread melting of snow and ice and rising global sea levels. The extra heat in the climate system has other impacts such as affecting atmospheric and ocean circulation, which influences rainfall and wind patterns.
Another serious impact of the increasing concentration of atmospheric carbon dioxide is ocean acidification. Around a quarter of the carbon dioxide produced by humans is absorbed by the oceans. As the carbon dioxide dissolves in sea water it forms a weak carbonic acid, making the ocean more acidic. There are early indications that some marine organisms are already being affected by ocean acidification.
The global average air temperature has increased by around 0.85 degrees Celsius since 1880.[i] The observed increase in temperatures has occurred across the globe, with rising temperatures recorded on all continents and in the oceans. World Meteorological Organization records show that the decade of 2001-10 was the world’s warmest decade on record, and that the 2000s were warmer than the 1990s which in turn were warmer than the 1980s. In Australia, average air temperatures have increased by around 0.9 degrees Celsius since 1910, and each decade has been warmer than the previous decade since the 1950s.[ii]
Scientists agree that the worst effects of climate change can largely be avoided if carbon dioxide emissions are reduced to an acceptable level."
So let's understand fossil fuels and their combustion........
Additional Resources
Many famous wine producers are buying land in Tasmania in response to climate change. Read about this in the article "Vineyards take action as climate change threatens wine and livelihoods."