The carbon cycle Human Impacts

Image from http://www. physicalgeography

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

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

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

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

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

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)

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

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