Climate & the Carbon Cycle
•Earth is a closed system. Carbon is not gained or lost, it just cycles through the different spheres (Atmosphere; Hydrosphere; Geosphere; Biosphere)
•Atmospheric CO2 is a GHG. It traps I.R. energy radiated from Earth’s surface; temperatures increase.
Climate Change: Global Warming
Global Warming = Increase in air and ocean temperatures.
Due to changes in Earth’s Energy Budget.
Greenhouse Effect & CO2
Greenhouse Gases = Gases that prevent I.R. wavelengths from E’s surface from escaping to outer space.
CO2 = GHG
Measuring Carbon Dioxide in the Atmosphere
•Ice Cores: Gas bubbles trapped in ice are miniature atmospheres that can be studied.•Measured directly from. Mauna Loa
Carbon Dioxide Levels
•CO2 levels are determined from gas bubbles trapped in ice (Vostock Lake, Antarctica)•Temperatures can be determined from 18O:16O ratios.
• CO2 levels are determined from gas bubbles trapped in ice (Vostock Lake, Antarctica)• Temperatures can be determined from 18O:16O ratios.
Evidence of Global Warming: Measured increases in Carbon Dioxide Levels
Modern CO2 levels measured at Mauna Loa Observatory, Hawaii
Evidence of Global Warming: Increasing Sea Surface Temperatures & Sea Level Rise
Evidence of Global Warming: Glacial Retreats
Carbon Cycle: Key IdeasReservoirs: a term used to describe the compartments that contain carbon in some form (e.g.: atmosphere, soil, water, in plants, etc)
Photosynthesis: CO2 from atmosphere turned into “sugar”
Respiration: cells convert sugars from food into CO2
Fossilization: processes involving extreme pressures that turn various kinds of carbon into fossil fuels (coal, crude oil, natural gas)
Sedimentation: material settles to bottom of aquatic system
Food Chain: carbon is transferred up the food chain as animals consume plants and other animals. Eventually, upon death, the carbon is returned to soil and sediments.
Volcanism: volcanoes can cycle carbon back to the atmosphere. As rock melts to form magma, carbonate (CO3
-2) is turned into CO2
Chemical Weathering: Carbon dioxide from air dissolves in water to form carbonic acid. Carbonic acid weathers rock surfaces.
Combustion: fires or burning of fossil fuels returns carbon to the atmosphere
Atmospheric CO2
Carbon in Trees, Plants,
Algae
CO2
Dissolved in Ocean
Carbon in Animals
Carbonate (CaCO3)
in shells, etcCarbon in Sediment
Carbon in Fossil Fuels
Carbon in Soil
Carbonate (CaCO3)
Rock (limestone)
uptake
dissolving
Uplift & Mt. Building exposes
new rock
Atmospheric CO2
Carbon in Trees, Plants,
Algae
CO2
Dissolved in Ocean
Carbon in Animals
Carbonate (CaCO3)
in shells, etc
Carbon in Sediment
Carbon in Fossil Fuels
Carbon in Soil
Carbonate (CaCO3)
Rock (limestone)
Resp
irationResp
iration
Bact
eria
l Res
pira
tion
photosynthesis
Food Chain
fossilization pressure
uptakeChem
ical
weathering
burn
ing
fires dissolving
Uplift/Mt. Buidling exposes
new rock
volcanoes
•Volcanism ADDS CO2 to the atmosphere.•Mt. Building & the chemical weathering of new rock REMOVES CO2 from the atmosphere.
Geosphere Atmosphere
Geosphere Atmosphere
Atmosphere Hydrosphere Geosphere
CO2 gas Dissolved CO2 used by plankton which die
Plankton settle to bottom of ocean floor. Sediment
layers become rock.
Biosphere Geosphere
•Plankton use dissoved CO2 in water for photosynthesis.•Plankton die (or are consumed/decomposed by other organisms, which die).•Dead plankton bring carbon to the ocean floor where it will become ROCK.
Warming or Cooling?
Increased volcanism? Increase in mountain building & weathering? Deforestation? Increased photosynthesis by marine plankton? Increased frequency of forest fires? Increased combustion of fossil fuels?Decreased volcanic activityIncreased use of solar energy or wind power.
Ways to Reduce atmospheric CO2?
Reduced volcanism? Mountain building & increased weathering? Increased photosynthesis? Increased absorption of CO2 by ocean? Changing land use (forests, urban areas, etc.)?Increase the amount or rate that carbon becomes rock?Decrease combustion of fossil fuels?
Results of increased levels of CO2
Increased atmospheric and sea surface temperature.Ice caps/glaciers melt.Flooding of coastal areas due to sea level rise.Droughts in some locations/increased productivity in others.Decrease in salinity of ocean water changes ocean circulation (& climate patterns).Ocean acidification (dissolved CO2 forms an acid in water) reef organisms dissolveIncrease in insect borne (tropical) diseases (Malaria, etc.)Economic loses.
Results of Global Warming•Flooding due to rise in sea level.•Change in “who” grows food.•Coral reefs die b/c acidification.
Top Related