Earth and Space Science / Unit 8: Climate
8.5 The Greenhouse Effect and Carbon Cycle
Notes
- Greenhouse gases (carbon dioxide, methane, water vapor, nitrous oxide) absorb heat from Earth and radiate some back.
- The carbon cycle moves carbon among the atmosphere, oceans, living things, rocks and fossil fuels.
- Burning fossil fuels (coal, oil, gas) and clearing forests adds CO₂ to the atmosphere.
- Carbon dioxide has risen from about 280 ppm (before 1800) to over 420 ppm today.
- Oceans absorb CO₂, which makes seawater more acidic (ocean acidification).
- Example: a rise from 280 to 420 ppm is $\displaystyle \frac{140}{280} = 50\%$ increase.
Practice
Burning fossil fuels increases atmospheric:
Carbon stored for millions of years is released.
CO₂ rose from 280 ppm to 420 ppm. The percent increase is:
$(420-280) \div 280 = 0.5$.
Which is a natural process that removes CO₂ from the air?
Plants take in CO₂.
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