Climate Change Weather vs Climate Earths energy supply

Climate Change • Weather vs. Climate • Earth’s energy supply • The atmosphere • Greenhouse gases • The greenhouse effect • Enhanced greenhouse effect • The role of the carbon cycle • Effects of global warming • Historic climate change • Climate proxies • What you can do

Bill Nye – Climate Change

Weather vs. Climate Weather: atmospheric conditions, including temperature, precipitation, wind, and humidity, in a particular location over a short period of time, such as a day or a week Climate: the average of the weather in a region over a long period of time

Air Convection Currents • Large convection air currents occur over the world because cool air is more dense than warm air. • These convection currents can greatly affect the weather in a given region.

Air Currents and Large Bodies of Water • During the summer, large bodies of water absorb a lot of heat – This will cause the climate to be more moderate in summer near the coast. • In winter, the water near the coast will slowly release this energy, – This will cause coastal areas to be less cold, in general, than inland areas in the winter.

Let’s Talk Energy Supply. . . • The SUN provides the earth with most of its energy. – Warms the Earth – Used by plants (photosynthesis) to produce carbohydrates (glucose)

Components of the Earth’s Climate System • The Atmosphere – Layers of gas – Ozone in Stratosphere protects from the sun’s harmful UV rays. • The Hydrosphere – Water, Water Vapour, Ice – Absorbs the sun’s energy – Water Cycle • The Lithosphere – Earth’s Crust (Land) – Absorbs the sun’s energy

Atmosphere • We can only survive in the Troposphere • Air in the troposphere is 78% N 2, 21% O 2 and 1% other gases including Ar, CO 2, He, H and O 3

The Ozone Layer • The Ozone (O 3) Layer is located between the stratosphere and the troposphere and helps protect us from UV light from the sun. • Ozone depletion is caused by human-made compounds called chlorofluorocarbons (CFC’s) – Many CFCs have been widely used as refrigerants and propellants (in aerosol applications). Their manufacture has been phased out due to their harmful affects.

• High-energy radiation from the Sun enters the atmosphere. Gases and clouds in the atmosphere trap some of the infrared radiation from Earth’s surface and radiate it back. This is the Greenhouse effect.

Infrared (long-wave) Radiation

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The Greenhouse Effect

Greenhouse Gases • Any gas in the atmosphere that absorbs infrared radiation from the Earth • Most of the air in the atmosphere is made of N 2 and O 2 which do not absorb radiation from the surface of the Earth

Greenhouse Gases • Greenhouses gases include H 2 O, CO 2, CH 4, N 2 O, CFC’s and a few others • They are very low in concentration • It is their concentration in the atmosphere which determines how much energy they can absorb

The Greenhouse Effect

The Greenhouse Effect • The heat from the natural greenhouse effect warms Earth’s atmosphere an average of 33°C • Eventually, this heat dissipates to outer space • If there were no greenhouse effect, Earth’s average temperature would be -19°C

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Climate Change

Greenhouse Gases • Consist of less than 1% of the atmosphere • Produced “naturally” and by human activities

Enhanced Greenhouse Effect (Human impact on the Greenhouse Effect) • Humans are increasing the concentrations of greenhouse gases but by how much? ? ? • What impact do we have? What is the greenhouse effect?

Water Vapour (95% of Earth’s greenhouse effect) • Part of the “natural” greenhouse effect - Human activities do not release significant amounts of water vapour into the atmosphere -remains on average for 9 days • Most abundant greenhouse gas • Water vapor constitutes Earth's most significant greenhouse gas, accounting for about 95% of Earth's greenhouse effect

However … • Although humans do not directly control the amount of water vapor in the atmosphere, we have a large, indirect affect on it Recall: Warm air has a greater ability to hold water • By enhancing the greenhouse effect, humans are increasing the temperature of the air and therefore, increasing the ability of air to hold water • An increase in water vapor further enhances the greenhouse effect and contributes to global warming

Nitrous oxide • Produced when wood and fossil fuels are burned • Produced by chemical industry and released by bacteria from fertilizers • Traps heat 296 times better than carbon dioxide

Carbon Dioxide • Released when fossil fuels- coal, oil and natural gas- are burned • Increases due to the removal and burning of forests, industrial processes such as the manufacture of cement, and the cultivation of soil

Global Warming and the Carbon Cycle However the general consensus is that an increase in CO 2 is directly responsible for Global Warming. Why?

CO 2 and Temperature

Where is all the Carbon? • Inorganic Carbon – The Atmosphere – The Ocean – The Earth’s Crust • Organic Carbon – Bodies of Living Things – Fossil Fuels

Where is all the Carbon? • Most of the worlds Carbon is held in Carbon Sinks which is a reservoir, such as an ocean or forest, that absorbs carbon dioxide from the atmosphere and stores the carbon in another form (H 2 CO 3)

Human Impact on the Carbon Cycle Humans affect the carbon cycle by: • releasing carbon into the atmosphere faster than would normally occur (burning fossil fuels/wood). • clearing away vegetation (cutting down forests).

Human Impact on the Carbon Cycle

The Carbon Dioxide Positive Feedback Loop • Oceans are large Carbon sinks. As temperatures increase, more ocean water evaporates releasing the carbon into the atmosphere which further increases the temperature. This then repeats.

CO 2 and Temperature

Evidence of Climate Change • Earth’s average temperature has generally increased from 1880 to 2006. • What else could account for this increase?

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Who Cares? ? ?

Effects of Global Warming The impacts of climate change are predicted to be serious and widespread: • more violent weather • Increases in global temperatures melting glaciers, increase in sea levels, flooding • Ecosystems Creating unsuitable habitats (melting ice and polar bears) • Shifting patterns of rainfall and drought

1928 South Cascade Glacier, Washington 1979 South Cascade Glacier, Washington 2003 South Cascade Glacier, Washington A growing body of evidence indicates that humans now have a significant impact on climate by affecting the carbon cycle.

Why? Look it up. • An increase in global temperature will create in increase in disease-carrying organism populations like certain types of mosquitoes which will lead to increased disease rates such as West Nile, Malaria, etc. ).

Human Health • “Worldwide increases in the incidences of asthma, allergies, infectious and cardiovascular diseases will result from a variety of impacts of global climate change, including rising temperatures, worsening ozone levels in urban areas, and expansions of the ranges of communicable diseases as the planet heats up” http: //www. ucdmc. ucdavis. edu/publish/newsroom/6320

Has abrupt climate change happened before?

YES

Long-Term Cycles in Climate • Over the last 800, 000 years or more, Earth’s climate has cycled between freezing ice ages and warmer interglacial periods • We experience an Ice Age approximately every 100, 000 years

Previous Ice Age

Prehistoric Climate Changes • Climate proxies are preserved physical characteristics of the past that enable scientists to reconstruct historic climate conditions Examples include: • Pollen records • Ice core samples • Marine corals • Fossils

What can you do? Make a List • Choose reusable products • Use less heat and air conditioning • Buy energy-efficient products • Drive less • Turn lights off • Buy local products • Plant a tree