4.3 Carbon Cycling and 4.4 Climate Change © 2007 Paul Billiet ODWS

Essential idea Continued availability of carbon in ecosystems depends on carbon cycling.

Carbon Cycle (Key Understandings) CO2 Understandings: Carbon dioxide diffuses from the atmosphere or water into autotrophs. Autotrophs convert carbon dioxide into carbohydrates and other carbon compounds.

Carbon Cycle (Key Understandings) CO2 Understandings: In aquatic ecosystems carbon is present as dissolved carbon dioxide and hydrogen carbonate (bicarbonate) ions.

Carbon Cycle (Key Understandings) CO2 Understandings: Carbon dioxide is produced by respiration and diffuses out of organisms into water or the atmosphere. Carbon dioxide is produced by the combustion of biomass and fossilized organic matter.

Carbon Cycle (Key Understandings) Methane Understandings: Methane is produced from organic matter in anaerobic conditions by methanogenic archaeans and some diffuses into the atmosphere or accumulates in the ground. Methane is oxidized to carbon dioxide and water in the atmosphere.

Carbon Cycle (Key Understandings) Fossils and Fossil Fuel Understandings: Peat forms when organic matter is not fully decomposed because of acidic and/or anaerobic conditions in waterlogged soils. Cross section of tropical peat, bulldozed to make way for a highway https://cee.mit.edu/node/20162 peat

Carbon Cycle (Key Understandings) Fossils and Fossil Fuel Understandings: Partially decomposed organic matter from past geological eras was converted either into coal or into oil and gas that accumulate in porous rocks. Peat formed coal after being buried, compressed, and heated. Oil and natural gas formed in mud at the bottom of bodies of water

Carbon Cycle (Key Understandings) Fossils and Fossil Fuel Understandings: Animals such as reef-building corals and mollusca have hard parts that are composed of calcium carbonate and can become fossilized in limestone.

Applications and skills: Application: Estimation of carbon fluxes due to processes in the carbon cycle. Carbox flux = exchange of carbon between the atmosphere, oceans and/or biosphere Guidance: Carbon fluxes should be measured in gigatonnes.

Applications and skills: Nature of science: Making accurate, quantitative measurements—it is important to obtain reliable data on the concentration of carbon dioxide and methane in the atmosphere. (3.1) Application: Analysis of data from air monitoring stations to explain annual fluctuations. See next slides… Be able to explain annual fluctuations.

Mauna Loa Data © Mauna Loa Observatory Site

South Pole Data

Skill: Diagram the Carbon Cycle (note: include photosynthesis, respiration, fossilization and combustion)

4.4 Climate Change Essential idea: Concentrations of gases in the atmosphere affect climates experienced at the Earth’s surface. Global temperatures and climate patterns are influenced by concentrations of greenhouse gases including: H2O vapour CO2 CH4 NOx (oxides of nitrogen) Percent effect of different gases on climate

The Greenhouse Effect A natural and important effect. Without an atmosphere the Earth would have about the same temperature as the moon Moon mean surface temperature -46°C Moon temperature range: -233 to +123°C © 2007 Paul Billiet ODWS

Greenhouse Gases and Climate Radiation from the sun hits earth. This is absorbed and re-radiated as longer wavelength radiation (heat) Longer wavelength radiation is absorbed by greenhouse gases that retain the heat in the atmosphere. Video: Inconvenient truth (scenes 3-4) •

The Greenhouse Effect © Oceanworld 2005 Robert R Stewart

2013 U.S. Greenhouse Gas Emissions Greenhouse Gases The impact of a gas depends on its ability to absorb long wave radiation as well as on its concentration in the atmosphere Carbon dioxide and water vapour are the most significant greenhouse gases. (abundant in atmosphere) Other gases including methane and nitrogen oxides have less impact. (less abundant) 2013 U.S. Greenhouse Gas Emissions http://www3.epa.gov/climatechange/ghgemissions/gases.html image source

There is a correlation between rising atmospheric concentrations of carbon dioxide since the start of the industrial revolution 200 years ago and average global temperatures. Recent increases in atmospheric carbon dioxide are largely due to increases in the combustion of fossilized organic matter.

Since the Industrial Revolution Concentration of Carbon Dioxide from trapped air measurements for the DE08 ice core near the summit of Law Dome, Antarctica. (Data measured by CSIRO Division of Atmospheric Research from ice cores supplied by Australian Antarctic Division)

Levels during the last ice age © Dennis Hartmann: University of Washington: Department of Atmospheric Sciences

Application: Correlations between global temperatures and carbon dioxide concentrations on Earth.

http://faculty.virginia.edu/setear/courses/globwarm/images.htm

Application: Threats to coral reefs from increasing concentrations of dissolved carbon dioxide. Ocean Acidification: Reduced availability of Calcium Carbonate for production of coral exoskeletons/shells of other organisms (see comic, next slide) Coral Bleaching: Corals are sensitive to temp. changes and lose zooxanthellae. Bleached coral, Great Barrier Reef

Is this a problem? Discuss: What are some potential effects of climate change that you know of?

The Precautionary Principle Global warming might cause catastrophic consequences Therefore, people should take preventive measures to avoid contributing to the problem (ex. Emit fewer greenhouse gases) The burden of proof lies on those who say that human emission of greenhouse gases will do no harm. Evaluate this principle as justification for strong action in response to the threats posed by the enhanced greenhouse effect.

Theory of knowledge: • The precautionary principle is meant to guide decision-making in conditions where a lack of certainty exists. Is certainty ever possible in the natural sciences?

Nature of science: Assessing claims—assessment of the claims that human activities are producing climate change. (5.2) Application: Evaluating claims that human activities are not causing climate change. Discuss your thoughts Climate Change Database Investigation (computer lab)

International-mindedness: Release of greenhouse gases occurs locally but has a global impact, so international cooperation to reduce emissions is essential.

End of IB

Potential effects Sea level rise Climate change Flooding coastal areas Reduced agricultural land Displacement of populations Climate change Displacement of ecosystems Change in range of insect vectors of pathogens Reduced biodiversity Weather changes (ex: Storms increasing in frequency and/or severity) © 2007 Paul Billiet ODWS

Potential effects Increased rates of photosynthesis Increased agricultural production at high latitudes BUT faster growth means: less protein in cereals trees taller and more exposed to storm damage © 2007 Paul Billiet ODWS

Effects on Arctic Ecosystems increased rates of decomposition of detritus previously trapped in permafrost expansion of the range of habitats available to temperate species loss of ice habitat changes in distribution of prey species affecting higher trophic levels increased success of pest species,including pathogens.

Is it really getting warmer 1979 2003 © NASA Click on NASA link to see animation etc…

The melting Arctic ice The length of the melt season inferred from surface temperature weekly data has been increasing by 9, 12, 12, and 17 days per decade in sea ice covered areas © NASA

The Greenhouse Gases Water vapour in the atmosphere is stable CO2 levels are currently rising They have varied in the past Methane levels are increasing: as more cattle are farmed, as more paddy fields are planted, as permafrost melts NOx (oxides of nitrogen) levels increase due to increased circulation of motor vehicles © 2007 Paul Billiet ODWS

Mauna Loa Observatory © Mauna Loa Observatory Site © Earth System Research Laboratory © Earth System Research Laboratory

Carbon dioxide a greenhouse gas © Mauna Loa Observatory Site

South Pole Data

Samoa data

© Australian Antarctic Division © New Scientist : Environment

Out of the ice age

The Greenhouse Gases (know them) H2O vapour CO2 CH4 NOx (oxides of nitrogen) CFC © Oceanworld 2005 Robert R Stewart © Text 2007 Paul Billiet ODWS

The oceanic conveyor belt

What can be done? Reduce carbon emissions Improve mass transport systems (public transport) Design more efficient motors Design alternative power sources Hydrogen powered motors BUT problems of fuel reservoir, delivery, fabrication Renewable energy (wind, tidal, hydro, geothermal, biomass) BUT growing crops for biofuel reduces farmland available for food Hydroelectric dams disrupt river ecosystems Nuclear power BUT problems of nuclear waste treatment/storage © 2007 Paul Billiet ODWS

What can be done? Increase natural CO2 sequestering Reduce deforestation Increase reforestation © 2007 Paul Billiet ODWS

What can be done? Artificial CO2 sequestering Filter CO2 sources using hydroxide scrubbers Injection of CO2 into deep ocean layers Forms CO2 reservoirs Impact on sea life unknown Injecting CO2 into disused oil wells Mineral deposition as carbonates © 2007 Paul Billiet ODWS

Alternative Energy Sources… http://science.howstuffworks.com/free-energy-flush.htm http://science.howstuffworks.com/five-forms-alternative-energy.htm

The bottom line Two factors will ultimately govern what happens: 1. Human population growth More people means greater demand for non-renewable resources 2. The ecological footprint of each individual human Higher standards of living usually means higher consumption of fossil fuels The planet will look after itself in the end There are plenty of examples where human communities have disappeared because they outstripped the environmental resources © 2007 Paul Billiet ODWS

The planet will look after itself in the end Easter Island (Rapanui) in the Pacific Settled between AD900 and 1200 Community in severe decline AD 1700 Cause: excessive deforestation The Moai statues, Easter Island © Martin Gray, World Mysteries © Text 2007 Paul Billiet ODWS

The planet will look after itself in the end Chaco Canyon, New Mexico Anasazi culture AD 850 – 1250 Cause: Deforestation combined with a decline in rainfall © New Mexico Tourism Department © Text 2007 Paul Billiet ODWS

The planet will look after itself in the end Mesopotamia Sumerian civilization 3100 – 1200 BC Increased salt levels in soil due to irrigation systems & arid environment Reduced food yield © Asociación Cultural Nueva Acrópolis en Barcelona © Text 2007 Paul Billiet ODWS

The planet will look after itself in the end Greenland Viking colony AD982 – 1350 Cause: Deforestation, soil degradation & cooling of the climate © Emporia State University © Text 2007 Paul Billiet ODWS

Who’s next? forumpolitics.com/pics/earth-photo.jpg © NASA