The Greenhouse Effect = GOOD  The Earth’s atmosphere acts like the glass of a greenhouse by trapping some heat in the atmosphere. Without this, the Earth would be too cold for life to exist!

Earth’s Albedo Effect (surface reflection) Some of the light penetrating the atmosphere reflects off of the Earth’s surface and bounces back out into space. 3

Absorption and Conversion to Heat Some of the light energy reaching the surface is absorbed by Earth’s surface. In the process, visible light energy is transformed into heat energy and certain characteristics are altered. 4

Greenhouse Gases Greenhouse Gases - gases that absorb and radiate heat Major greenhouse gases: Water vapor Carbon dioxide Methane Nitrous Oxide

Sources of various greenhouse gases: Natural Sources Anthropogenic (Man-made) Carbon Dioxide * Cellular respiration & decay * Natural fires * Volcanoes * Warming oceans * Combustion of fossil fuels * Land use conversion * Cement production Methane * Animal digestion * Methane hydrates * Rice paddies * Livestock * Landfills Nitrous Oxide Temperate & tropical soils * Oceans * Fertilizer * Industrial processes Water Vapor Oceans Water Cycle – evaporation, condensation 6

The major role of carbon dioxide can be appreciated by comparing its influence on our planet relative to that of our nearest neighbors in the solar system. Image: (United Nations Environment Programme & GRID-Arendal, 2010) 7

in turn allows more CO2 to move from the atmosphere into the ocean. Most cycling is not directly related to humans. It has the following major components: • Carbon dioxide is taken out of the atmosphere directly through photosynthesis occurring on land. • Dissolved CO2 is taken out of the ocean waters through photosynthesis, which in turn allows more CO2 to move from the atmosphere into the ocean. • Carbon dioxide is returned to the atmosphere through cellular respiration on both land (directly) and in the oceans (indirectly). This includes the CO2 released through decomposition. • Carbon dioxide is also released through fires and volcanism. 8

Throughout our planet’s history, natural processes have kept CO2 and global temperature in close correlation. 9

Carbon dioxide levels are rising Why? – burning of fossil fuels & deforestation Millions of tons of CO2 released a year from power plants (burning coal or oil) & cars (burning gasoline) Millions of trees are burning in tropical forests to clear land for farming

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What might rising CO2 do? the average global temperature during the 20th century. Experiments & models show that increased GHGs may be causing the rapid temperature increase

Global Warming = BAD  (The Enhanced Greenhouse Effect)

Effects of Global Warming Circadian Clocks Change Some birds have been nesting a few days earlier than they did 50 years ago. Some plants are flowering earlier than before. Effects of Global Warming

Rapid Changes in FLOWERING Time in British PLANTS A. H. Fitter,1* R. S. R. Fitter2 The average first FLOWERING date of 385 British plant species has advanced by 4.5 days during the past decade compared with the previous four decades: 16% of species flowered significantly EARLIER in the 1990s than previously, with an average advancement of 15 days in a decade. Ten species (3%) flowered significantly later in the 1990s than previously. These data reveal the strongest biological signal yet of climatic change. FLOWERING is especially sensitive to the temperature in the previous month, and spring-FLOWERING species are most responsive. However, large interspecific differences in this response will affect both the structure of plant communities and gene flow between species as climate warms. Annuals are more likely to flower early than congeneric perennials, and insect-pollinated species more than wind-pollinated ones.

Effects of Global Warming Polar ice is melting - Polar bears endangered - Less solar radiation reflected - Rising sea levels/Coastal flooding Circadian Clocks Change Some birds have been nesting a few days earlier than they did 50 years ago. Some plants are flowering earlier than before. Effects of Global Warming

Effects of Global Warming Circadian Clocks Change Some birds have been nesting a few days earlier than they did 50 years ago. Some plants are flowering earlier than before. Polar ice is melting - Polar bears endangered - Less solar radiation reflected - Rising sea levels/Coastal flooding Effects of Global Warming Global Weather Patterns Oceans may absorb more heat, which may make hurricanes and typhoons more common. Gulf Stream may shut off, changing the world’s weather significantly

Effects of Global Warming Circadian Clocks Change Some birds have been nesting a few days earlier than they did 50 years ago. Some plants are flowering earlier than before. Polar ice is melting - Polar bears endangered - Less solar radiation reflected - Rising sea levels/Coastal flooding Effects of Global Warming Global Weather Patterns Oceans may absorb more heat, which may make hurricanes and typhoons more common. Gulf Stream may shut off, changing the world’s weather significantly Human Health Problems Heat related deaths Allergies (plants in bloom longer) Mosquitoes thrive in heat Agriculture would be effected by droughts

Intergovernmental Panel on Climate Change (IPCC) Network of ~2500 world’s leading climatologists from 70 countries. They have concluded that: the global surface temperature has increased by 0.6°C during the 20th century snow & ice cover has decreased, the average global sea level has risen greenhouse gases have continued to increase

Kyoto Protocol A treaty that requires developed countries to decrease emissions of carbon dioxide & other greenhouse gases by an average of 5% below their 1990 levels by 2012. ** The USA has not signed this protocol

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