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/