Global WarmingGlobal Warming

Rising Levels of Greenhouse GasesRising Levels of Greenhouse Gases

Carbon dioxide accounts for 49% of Carbon dioxide accounts for 49% of the human-caused input of greenhouse the human-caused input of greenhouse gases.gases.

Major Sources of COMajor Sources of CO22 input: input:

Fossil-fuel burningFossil-fuel burning 80%80%

DeforestationDeforestation 20%20%

COCO22 remains in the atmosphere for about 500 years once it gets there. remains in the atmosphere for about 500 years once it gets there.

Industrial countries account for about 76% of the annual emmissionsIndustrial countries account for about 76% of the annual emmissions

Chlorofluorocarbons (CFC’s) Chlorofluorocarbons (CFC’s) account for 14% of the human account for 14% of the human input of greenhouse gases.input of greenhouse gases.

CFC’s generally have 10,000 CFC’s generally have 10,000 to 20,000 times the impact on to 20,000 times the impact on global warming per molecule global warming per molecule when compared to COwhen compared to CO22

CFC’s stay in the atmosphere 65 to 111 years and also contribute to ozone CFC’s stay in the atmosphere 65 to 111 years and also contribute to ozone depletion.depletion.

Major Sources:Major Sources: Leaking air conditioners and refrigeratorsLeaking air conditioners and refrigeratorsEvaporation of industrial solventsEvaporation of industrial solventsProduction of plastic foamsProduction of plastic foamsPropellant in aerosol cansPropellant in aerosol cans

Methane (CHMethane (CH44) is responsible ) is responsible

for 18% of the human input of for 18% of the human input of greenhouse gases. It is greenhouse gases. It is produced by bacteria that produced by bacteria that decompose organic matter in decompose organic matter in anaerobic environments.anaerobic environments.

Natural sources produce Natural sources produce about 1/3 of the methane in about 1/3 of the methane in the atmosphere and include:the atmosphere and include:

Emissions from water logged soils, bogs, marshes, and rice paddiesEmissions from water logged soils, bogs, marshes, and rice paddiesThe gut of termitesThe gut of termitesThe gut of livestockThe gut of livestockCoal seamsCoal seams

Other sources include landfills, natural gas wells, pipelines, storage tanks, furnaces, etc.Other sources include landfills, natural gas wells, pipelines, storage tanks, furnaces, etc.

Methane stays about 7 to 10 years in the atmosphere and is about 25 times more Methane stays about 7 to 10 years in the atmosphere and is about 25 times more effective in warming the atmosphere when compared to COeffective in warming the atmosphere when compared to CO22

Nitrous Oxide (NNitrous Oxide (N22O) is responsible O) is responsible

for 6% of the human input of for 6% of the human input of greenhouse gases.greenhouse gases.

NN22O is released from the O is released from the

breakdown of nitrogen breakdown of nitrogen fertilizers in soil, livestock fertilizers in soil, livestock wastes, and nitrate wastes, and nitrate contaminated water. contaminated water.

NN22O is also created when biomass fuels are burned.O is also created when biomass fuels are burned.

It stays in the atmosphere for about 150 years and is 230 times more potent than It stays in the atmosphere for about 150 years and is 230 times more potent than COCO22 as a greenhouse gas. as a greenhouse gas.

Contributing CountriesContributing CountriesUnited StatesUnited States 18%18%European CountriesEuropean Countries 13%13%Soviet UnionSoviet Union 12%12%BrazilBrazil 11%11%ChinaChina 7% 7%IndiaIndia 4% 4%JapanJapan 4% 4%CanadaCanada 2%2%MexicoMexico 1.4% 1.4%

Greenhouse Gas Emission EffectsGreenhouse Gas Emission EffectsWhile there is no doubt greenhouse gases are being emitted into the atmosphere While there is no doubt greenhouse gases are being emitted into the atmosphere at increasing rates, the effect of these emissions is a subject for debateat increasing rates, the effect of these emissions is a subject for debate

First, the effect on global temperature is widely debated. Reliable First, the effect on global temperature is widely debated. Reliable temperature measurements are only available from 1880. Since that time the temperature measurements are only available from 1880. Since that time the temperature has only risen slightly or by some estimates has even fallen.temperature has only risen slightly or by some estimates has even fallen.

Since this amount is so small the normal short-term temperature swings have Since this amount is so small the normal short-term temperature swings have not been exceeded.not been exceeded.

Global Temperature MeasurementsGlobal Temperature Measurements

Sea Level TrendsSea Level Trends

PrecipitationPrecipitation

SO….What will happen?SO….What will happen?

Current models project the earth’s temperature will rise 1.5 Current models project the earth’s temperature will rise 1.5 5.55.5ooC over the next 50 years.C over the next 50 years.

There are many uncertainties in this modeling. Modelers There are many uncertainties in this modeling. Modelers believe their models are accurate to within a factor of two.believe their models are accurate to within a factor of two.

This means the actual warming may be between 0.7This means the actual warming may be between 0.7ooC and C and 1111ooC. That is 10 to 100 times faster than has occurred during C. That is 10 to 100 times faster than has occurred during the last 10,000 years. A rise of 1.5the last 10,000 years. A rise of 1.5ooC would make the earth C would make the earth warmer than it has been in the last 100,000 years.warmer than it has been in the last 100,000 years.

Local EffectsLocal Effects

It is very difficult to model the effect global warming would have It is very difficult to model the effect global warming would have on any one particular area, but many estimates have been made.on any one particular area, but many estimates have been made.

It is reasonable to suppose that sea levels would rise and It is reasonable to suppose that sea levels would rise and precipitation patterns would change.precipitation patterns would change.

This would obviously cause many problems: flooding, food This would obviously cause many problems: flooding, food production problems, etc.production problems, etc.

What can be done?What can be done?

Input approachesInput approaches

Ban production of CFC’sBan production of CFC’sCut fossil fuel useCut fossil fuel useImprove energy efficiencyImprove energy efficiencyShift to alternative energy sourcesShift to alternative energy sourcesPromote energy efficiency in lesser developed countriesPromote energy efficiency in lesser developed countriesIncrease use of nuclear powerIncrease use of nuclear powerTax gasoline and emissionsTax gasoline and emissionsReduce use of coalReduce use of coalCapture methane released from landfills\Reduce beef productionCapture methane released from landfills\Reduce beef productionStop DeforestationStop DeforestationSlow population growthSlow population growth

Output ApproachesOutput Approaches

Develop methods to remove CODevelop methods to remove CO22 from stack gases. from stack gases.

Plant treesPlant treesRecycle CORecycle CO2 2 in industrial processes in industrial processes

Stimulate removal of COStimulate removal of CO22 from atmosphere by photosynthesis from atmosphere by photosynthesis

Individual ActionsIndividual Actions

Be aware of your COBe aware of your CO22 emissions and reduce them emissions and reduce them

Reduce your use and unnecessary waste of energyReduce your use and unnecessary waste of energyDon’t use electricity to heat space or waterDon’t use electricity to heat space or waterMake your home energy efficientMake your home energy efficientUse alternative energy sourcesUse alternative energy sourcesUse natural gas where you can in place of electricityUse natural gas where you can in place of electricityPlant treesPlant treesReduce, Reuse, RecycleReduce, Reuse, RecycleBuy reusable productsBuy reusable productsSupport appropriate legislationSupport appropriate legislation