Carbon Cycles Climate Change 4 3 4 4
Carbon Cycles & Climate Change (4. 3 -4. 4) IB Diploma Biology
The Carbon Cycle
It’s not just Carbon Dioxide… • Methane! (Oxidized to Water and CO 2) • Methanogenesis: Methane is produced from organic matter in anaerobic conditions by archaeans and some diffuses into the atmosphere. • Archaea are single-celled prokaryotic microorganisms that share some traits of bacteria and some of eukaryotes
Peat Formation • Soil-like peat forms when organic matter is partially decomposed in anaerobic conditions in waterlogged soils. • Peatlands contain 180 -455 billion tons of sequestered carbon and release 20 -45 million tons of methane, annually
Coal, Oil, and Gas Formation • Partially decomposed organic matter from past geological eras was converted into oil and gas in porous rocks or into coal.
Combustion! • Reaction of hydrocarbons (like fossil fuels) with heat and oxygen to release energy and produce CO 2 and water…
Limestone Formation • Animals such as reef-building corals and mollusks have hard parts that are composed of calcium carbonate and can become fossilized in limestone • An aquatic carbon sink
Carbon Fluxes
Monitoring of CO 2 • Atmospheric monitoring stations • Ice cores
A Strong Correlation…
Greenhouse Gases • Carbon Dioxide, Water Vapor, Methane, Nitrous Oxides • The impact of a gas depends on its ability to absorb long-wave radiation as well as on its concentration in the atmosphere.
How it works • Energy in the form of short wave solar radiation is emitted toward earth. • 26% is reflected by the atomosphere, 19% absorbed by the atmosphere, 55% reaches earth’s surface. 4% of that is reflected to space and the remaining 51% is absorbed by earth’s surface and re-emitted as long wave infrared radiation.
• In a greenhouse, light penetrates the glass – incoming short-wave radiation • Light energy is converted to heat energy and is re-radiated – outgoing long-wave infrared radiation causing the greenhouse to warm up. • The heat is trapped and warms the atmosphere • The atmosphere around the Earth acts like a giant greenhouse.
Greenhouse Effect & Global Warming • The “greenhouse effect” & global warming are not the same thing. – Global warming refers to a rise in the temperature of the surface of the earth • An increase in the concentration of greenhouse gases leads to an increase in the magnitude of the greenhouse effect. (Called enhanced greenhouse effect) – This results in global warming
Climate Science “Controversy” • Some claim human actions are not main reason (or even any reason) for recent increases in carbon and global temperatures
Threats to Coral Reefs • Dissolved carbon dioxide increases acidity of oceans which breaks down calcium carbonate that makes up reefs
THE END
Bibliography / Acknowledgments Jason de Nys Chris Paine
- Slides: 30