1. Cycling of Matter & the Climate System

2. Biogeochemical Cycle
The natural process of circulation of matter where matter and energy are exchanged between the abiotic and biotic environment and back…
Places where matter is stored for longer periods are called stores (also called reservoirs).
Human activities alter the natural cycle.

3. Carbon Cycle & Climate Change
Major stores of carbon on earth:
Marine sediments and sedimentary rock
Millions / billions of years
Oceans
500 – 1000 years
Fossil fuels (coal, oil, gas)
Hundreds / millions of years
Vegetation, soil, organic matter
5 – 25 years
Atmosphere
50 – 500 years

4. Carbon cycle

6. Global Carbon Budget
The relative amounts of carbon in different stores
An accounting of the exchanges (incomes and losses) of carbon between the stores of the carbon cycle

7. How Human Activities Affect the Carbon Cycle
By changing the relative amounts of carbon in each store and the length of time the carbon remains in each store (eg. burning fossil fuels)
Releases more carbon compounds in a shorter time
Leads to a build-up in the atmosphere (negative feedback loop)
Oceans absorb more CO2
This causes oceans to become warmer and more acidic, which then decreases their ability to absorb CO2 (positive feedback loop)

8. Nitrogen Cycle & Climate Change
Recall:
NITROGEN FIXATION
Process by which atmospheric nitrogen in converted into usable forms (nitrates) for organisms
Lightning
Bacteria

9. How Humans Affect the Nitrogen Cycle

10. How Humans Affect the Nitrogen Cycle
Humans affect the nitrogen cycle through the addition of nitrogen to
the land (agriculture)
fertilizers
water (water pollution)
fertilizer runoff, algae, ocean “dead zones”
the atmosphere (air pollution)
ammonia (NH3) creating smog, greenhouse gas nitrous oxide (N2O), etc…

11. Reducing the Effect of Nitrogen on Climate Change
Less fertilizer use
Precision farming
Satellites and GIS determine exact locations that require fertilizers
WORK:
p. 337 #1-4, p. 340 #1-8