Global Biogeochemical Cycles3.docx

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Earth & Environmental Sciences
EESC 1158
Donald James

Part II Radioactivity Uranium and thorium are unstable, they decay spontaneously U soppntaneously emits a particle from its nucleus called an alpha particle (2 protons + 2 neutrons) U = “parent” , TH = “daughter” product TH is also unstable, and emits a beta particle - Beta particle = an electron discharged from the nucleus when a neutron split into a proton and an electron - This process is Radioactive Decay, eventually uranium (parent) decays to lead (daughter) - Rate at which this is called is “half life”  Relates to the age of the Earth in 2 ways.. a. As radioactive elements decay in the Earth they heat up the surrounding rocks b. Radiometric Dating Relates to the source of heat within the Earth that Lord Kelvin did not account for – taking much longer to cool than Kelvin thought Potassium-Argon Dating K40 – Ar40 Half Life = 1.3 Billion years IPCC >99% virtually certain > 95% extremely likely >90% very likely >66% likely >50% more likely than not Scientists have demonstrated that the amount of carbon dioxide in the atmosphere has increased dramatically since the beginning of the Industrial Revolution in the 1800’s .04% of the Composition of the Atmosphere Greenhouse Effect = Carbon Dioxide traps heat in the atmosphere and therefore warms the Earth Greenhouse Gases = Carbon Dioxide, Water Vapour, Methane, Nitrous Oxide and Ozone Amount of Carbon Dioxide being injected into the atmosphere as a result of burning fossil fuels has increased dramatically since the start of the Industrial revolution Fossil Fuel Emissions = Coal, Oil, Natural Gas Kyoto Conference – To slow global warming by developing an international treaty that sets limits on how much carbon dioxide and other greenhouse gases could be released by industries, machines, and vehicles 38 Industrial countries agreed to reduce their emissions to below 99’ levels by 2012 with different levels of reduction for different countries USA – 7% reduction; responsible for 25% of world’s emissions of CO2 Problem – even if they all reduced, this is still too small a reduction to significantly slow the rate of global warming; don’t account for the role of developing nations Climate Modeling A. Natural forcing – due to solar variations and volcanic activity B. Anthropogenic forcing – greenhouse gases and sulfate aerosols C. Both natural and anthropogenic forcing included G = 9.8 m/sec World Market Crash of 2008 Mathematics and Financial firms developed complex ways of investing the client’s money that they came to rely on arcane formulas to judge the risks they were taking on Those formulas/models are only reflections of the real world and sometimes can be misleading Scientists struggle with models in many fields as well.. Climate science, coastal erosion, nuclear safety – Because information is hard to come by Composition of Earth’s Atmosphere Amount of water vapor in the air varies with time and place If water vapor, dust and others were removed than the remaining clear dry air is similar anywhere on Earth Nitrogen – 78% Oxygen – 21% Argon - .93% Carbon Dioxide – 0.04% Atmosphere begins at the Earth’s land-sea surface and extends upward “Atmospheric Pressure” and altitude Atmospheric pressure = the weight of the air above a given surface Higher we go, the less
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