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MonthDayLectureActivityChap. Nov.21Ecosystems IIServices56 26Global C cycle56 Dec.3Thinking ecologically I 5Thinking ecologically II Eco. literacy 10Exam review 19Final examHere at 10:40 am
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Activity for Dec. 5 (last 20 points) How far did your food travel?
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Activity for Dec. 5 (last 20 points) How far did your food travel? 1.Choose a meal.
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Activity for Dec. 5 (last 20 points) How far did your food travel? 1.Choose a meal. 2.Record calories for all items in your meal.
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Activity for Dec. 5 (last 20 points) How far did your food travel? 1.Choose a meal. 2.Record calories for all items in your meal. 3.Record place of origin for all items your meal.
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Activity for Dec. 5 (last 20 points) How far did your food travel? 1.Choose a meal. 2.Record calories for all items in your meal. 3.Record place of origin for all items your meal. 4.Get on Yahoo! Maps and determine the distance between the places of origin and Gainesville.
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Activity for Dec. 5 (last 20 points) How far did your food travel? 1.Choose a meal. 2.Record calories for all items in your meal. 3.Record place of origin for all items your meal. 4.Get on Yahoo! Maps and determine the distance between the places of origin and Gainesville. 5.Sum up the calories for your meal, and the miles your meal traveled to get to you.
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Activity for Dec. 5 (last 20 points) How far did your food travel? 1.Choose a meal. 2.Record calories for all items in your meal. 3.Record place of origin for all items your meal. 4.Get on Yahoo! Maps and determine the distance between the places of origin and Gainesville. 5.Sum up the calories for your meal, and the miles your meal traveled to get to you. 6.Bring this data to class.
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Emissions of greehhouse gasses
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Sea level change in FL
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How will climate warming affect life in FL?
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Climate forcing factors = Factors causing climate to change
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Temperature Direct temperature measurements span 140 years Global temperature has increased about 1 deg C
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Greenhouse gases Earth Sun Atmosphere Some infrared radiation is absorbed by greenhouse gases warming Earth and lower atmosphere Some solar radiation is reflected by atmosphere More radiation is absorbed by Earth and warms it Infrared radiation (heat) is released from the Earth
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Greenhouse gases Greenhouse warming potential (GWP) -- takes into account the ability of a gas to absorb infrared radiation, and the lifetime of the gas in the atmosphere Gas[conc]GWP carbon dioxide (CO 2 )360 ppm1 methane (CH 4 )1745 ppb23 nitrous oxide (N 2 O)314 ppb296 CFC-11268 ppt4600 CFC-134 ppt14000 water (H 2 O)
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A diversion to the stratosphere… These gases affect the ozone layer in the stratosphere (GOOD OZONE) BUT this is not related to their effect as a greenhouse gas in the troposphere (BAD OZONE) CFC’s:
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The atmosphere Stratosphere Troposphere Earth Good ozone Bad ozone 0 to 10 km 10 to 45 km
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Ozone Good ozone shields the earth from UV radiation
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Ozone Good ozone shields the earth from UV radiation Bad ozone = smog; affects animal and plant health
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Picture of smog in LA
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Ozone Good ozone shields the earth from UV radiation Bad ozone = smog; affects animal and plant health Neither are climate forcing factors!
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Back to greenhouse gasses and climate forcing…
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Greenhouse gases Carbon dioxide is the largest single contributor to climate forcing Carbon dioxide contributes about half of total climate forcing from greenhouse gases
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Measurements of past atmosphere come from bubbles trapped in ice cores
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Past temperature recorded in oxygen isotopes; 4-12 deg C variation between ice ages
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These records show a correlation between greenhouse gas concentrations and temperature
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Greenhouse gases and temperature Current temperature increase a sharp change from past 1000 years Climate might otherwise be cooling,but this is speculation
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Greenhouse gases
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Greenhouse gas sources MethaneTg/yr Animals80 Termites40 Rice Paddies110 Wetlands115 Fuels180 Total525 Yellow text = anthropogenic source
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Nitrous OxideTg/yr Biomass burning2 Land use (agriculture)1.4 Denitrification (soil)5.7 Denitrification (ocean)2 Total11.1 Greenhouse gas sources
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Carbon DioxidePg/yr Fossil Fuel6.3 Land clearing1.7 Ecosystem respiration120 Ocean efflux105
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The global carbon balance (in Pg C year -1 ): From: IPCC 1995 5.5 1 Pg = 10 15 grams Fossil fuels + deforest. = atmosphere + oceans + ??? E ff + E df = atm + ocean + other + 1.8+ 1.6= 3.3 + 2.0
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Predicting climate
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Climate predictions General circulation models (GCM) are used to predict future climate Driven by physical processes that involve transfers of energy and water Used with different greenhouse gas ‘scenarios’ to predict climate in a future atmosphere
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GCM predictions Models are tested against climate records from the past Model predictions are compared with other similar GCM predictions GCM temperature predictions are typically quite accurate
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GCM predictions Global climate predicted to warm 1.5 - 6 deg C by 2050 if CO 2 increases at current rate. High latitudes & and land surfaces warm most. Washington DC now has 30 days over 90 deg F. Will have 85 days over 90 deg F.
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Gainesville is not predicted to change very much. Why?
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