Download - The carbon cycle
Human Impacts
THE CARBON CYCLE
• Image from http://www.physicalgeography.net/fundamentals/images/carboncycle.jpg
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/