Calculating Earth's Greenhouse Gas Absorption

In summary, the conversation discusses the impact of greenhouse gases on Earth's temperature and the percentage of infrared radiation absorbed by these gases. The group calculates the flux using the Stefan-Boltzman equation and arrives at a result of 81%. They continue to discuss their calculations and question whether their approach is correct.
  • #1
Brad_Ad23
502
1
Ok, here's the question.

Without the greenhouse gases in Earth's atmosphere the temperature would be 250K. With them it is 40K higher (290K). Using the Stefan-Boltzman equation for flux ( F = σT4) what is the percentage of infrared radiation leaving the Earth's surface taht is absorbed by the greenhouse gases?


I spent awhile on this and the best I could come up with is 18%. But if someone else knows how to do this, help will be appreciated. Thanks!
 
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  • #2
What is the σ? Post that and show how you used it to get 18%.
 
  • #3
σ is the Stefan-Boltzman constant... 5.67 x 10-8 J/m2K4.

I basically calculated the flux F1 for T = 250K and F2 for T = 290.
Then I did xF1= F2-F1 and solved for x.
 
  • #4
Okay, now what did you get for F1 and F2? I don't get 18%, I get 81%!
 
  • #5
Hmm, yes I got 81% too. But for some reason it looks like I then did 1-x.

Is the basic setup even right for approaching this problem?
 

Related to Calculating Earth's Greenhouse Gas Absorption

1. How do you calculate Earth's greenhouse gas absorption?

To calculate Earth's greenhouse gas absorption, you need to first measure the concentration of each greenhouse gas in the atmosphere. Then, you can use the atmospheric absorption spectra to determine how much energy each gas can absorb. Finally, you can combine these values to calculate the total greenhouse gas absorption.

2. What are the main greenhouse gases that contribute to Earth's warming?

The main greenhouse gases that contribute to Earth's warming are carbon dioxide, methane, nitrous oxide, and water vapor. These gases are able to absorb and trap heat in the atmosphere, leading to an increase in global temperatures.

3. How does the absorption of greenhouse gases lead to climate change?

When greenhouse gases absorb heat energy from the sun, they prevent it from escaping back into space. This leads to an overall warming of the Earth's atmosphere, which can have a variety of impacts on climate, such as melting ice caps, rising sea levels, and more frequent and severe weather events.

4. Can we measure the amount of greenhouse gases in the atmosphere?

Yes, we can measure the concentration of greenhouse gases in the atmosphere through various methods, such as taking air samples and using remote sensing techniques. These measurements help scientists track changes in greenhouse gas levels over time and understand their impact on the environment.

5. How can we reduce the amount of greenhouse gases in the atmosphere?

There are several ways we can reduce the amount of greenhouse gases in the atmosphere. One way is to decrease our use of fossil fuels and switch to renewable energy sources. Another way is to practice sustainable land use and agriculture, as well as implement technologies that capture and store carbon emissions. Individual actions, such as reducing meat consumption and using public transportation, can also make a difference in reducing greenhouse gas emissions.

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