The carbon cycle

1. The carbon cycle Human Impacts

2. Image from http://www.physicalgeography.net/fundamentals/images/carboncycle.jpg

3. The Overall trend: why the fluctuations? Seasonal variations in photosynthetic activity

4. Image from http://climate.nasa.gov/evidence/

5. Greenhouse effect vs climate change • The greenhouse effect helps trap infrared energy (heat) in our atmosphere – needed for life on Earth • Climate change is what happens when too many greenhouse gases have accumulated in the atmosphere, causing unnatural changes • CO2, CH4 (methane), and CF4 (carbon tertraflouride-the most potent and longest-lived) are carbon-containing greenhouse gases • Others include nitrous oxide, ozone, and water vapor

6. Image from http://www.eia.gov/oiaf/1605/ggccebro/chapter1.html

7. What do we do to affect the carbon cycle? • Burn fossil fuels (coal, oil, gas) • Destroy carbon sinks through actions like deforestation, slash and burn agriculture (turning forests into fields), using peat for fuel • These lead to • Increase in mean annual global temperatures (about 0.5° C in the last century) • Melting of glaciers and a rise in sea-level • Melting of frozen underwater methane stores—potentially very bad, since methane is a potent greenhouse gas • Ocean acidification

8. Ocean acidification • As you saw in the video, acidification can lead to: • Loss of marine biodiversity • Far-reaching effects in the food web • The possible death of phytoplankton (earth’s largest carbon sink)

9. More than one problem… • Acidic waters dissolve calcium carbonate shells, but • THEN, bicarbonate is formed, which can’t be taken in by these organisms • So not only are their shells dissolving, but it’s harder to repair the damage

10. http://centerforoceansolutions.org/climate/impacts/ocean-acidification/http://centerforoceansolutions.org/climate/impacts/ocean-acidification/