Disappearing Polar Ice and Polar Bears: thinner ice = faster melting and farther distance for bears to swim for food. If trends continue then Arctic may be ice-free during the summer within a decade.

Climate and Weather

Weather: short-term conditions or state of the atmosphere at a given time or place (temp., air pressure, cloud cover, and precipitation).

Climate: long-term weather in a particular area. Affected by: latitude, elevation, air masses, proximity to water body)

Precipitation: water (rain, snow, sleet, or hail that fails to or condenses on the ground).

Humidity: amount of water vapour in the air.

Meteorologist: person who studies atmospheric conditions, predicts weather.

The Sun

-All energy on Earth from solar radiation. Life depends on it…-Solar radiation absorbed by Earth is converted to thermal energy (total kinetic energy of the particles in a substance)- How much do we get? Depends on the angle of incidence.

1. Earth’s Biosphere: thin layer of Earth that can support life

2. Atmosphere- Gas layer (extends 300 km)- N2, O2 mostly (trace CO2, Ne, He, CH4 etc.)- Dust (abiotic and biotic particles) that affects air

quality (soot etc.)- Four layers (see handout)

3. Lithosphere: - Solid portion of the Earth’s crust and upper mantle –

home to humans, microorganisms, plants and animals.

- Plate tectonics move over mantle (volcanoes, mountains etc. affecting weather)

4. The Hydrosphere-All water on Earth- 97% salt water-3% fresh water- warmed by incoming solar radiation

Within the biosphere several Biomes exist. - biome is a geographical region with a defined climate-Six in Canada (see pg. 269):1.Tundra2.Boreal Forest3.Temperate Deciduous Forest4.Temperate Grassland5.Temperate Coniferous Forest6.Mountains

Layer Average Altitude from Earth’s surface (km)

Temperature range (C)

Characteristics

Troposphere

Stratosphere

Mesosphere

Thermosphere

Earth’s Atmospheric Layers

Use the information on page 266 of your text to fill in the following chart. Do not copy – put in your own words as a simple reference.

Natural Greenhouse Effect

---- Absorption of thermal energy by the atmosphere. Helps keep avg. temp to 14.7 C (2007).

Greenhouse gases: methane, CO2, nitrous oxide and water vapour.

Insolation: the amount of solar radiation received by a region on the Earth’s surface.

- depends on: latitude, characteristics of the lithosphere, atm., and hydrosphere in that region.

Net Radiation Budget:-Difference between incoming and outgoing radiation (see Figure 7.18). Should be zero but isn’t always (ex: equator, arctic)

- Also depends on the Albedo effect

-- ALBEDO EFFECT (the proportion of sun’s energy that is reflected). Forests (10% – 20%), Clouds (40% - 70%).

Changes in albedo: when ice melts, albedo decreases = warmer temp. Can also work to cool (i.e. volcano).

When incoming radiation = outgoing radiation the temp. remains constant.

Thermal Energy TransferThermal Energy Transfer

- Movement of energy from high temperature to low temperature.

Energy transferred three ways:

1. Radiation via electromagnetic waves: can be reflected or absorbed. Absorbed energy = inc. Kinetic energy = inc. Temperature and then emits infrared radiation.

2. Conduction through direct contact

3. Convection within fluids (liquids or gases). Movement of particles from one place to another.

• Stored energy in air and water is transferred by wind (from areas of high pressure to low pressure) and ocean currents.

Air at equator heats up = less dense, rises; cooler denser air above it sinks pushing warm air up

THE CORIOLIS EFFECT:

-Deflection of any object from a straight-line path by the rotation of the earth. -Causes wind going toward the equator to turn RIGHT in northern hemisphere and LEFT in the southern hemisphere.

GLOBAL WIND PATTERNS

-From convection currents and Coriolis effect- transfer thermal energy from warm to cold

JET STREAMS

-Band of fast moving air in the stratosphere.- high altitude so less friction = faster winds- changes affect severe weather (storms, cyclones etc.)-Important in weather prediction.

THERMAL ENERGY TRANSFER IN THE HYDROSPHERE

-Water covers 70% earth’s surface- recall water cycle: when water changes states, energy is either released or absorbed.

Ocean energy transfers:- Global winds drive ocean currents

The Natural Greenhouse Effect

-The warming of Earth resulting from the ability of the atmosphere to trap energy radiated from Earth’s surface.

- Atmosphere allows > half of solar energy in, surface absorbs it and releases it as thermal energy into air. Certain gases trap some energy = warmer earth. Without it, Earth would be – 18 C and all water would freeze!

Greenhouse gases occurring naturally: CO2, water vapour, methane and nitrous oxide.

- CFC’s, HFC’s created by humans (coolants in freezers etc.) among those listed above.

Global warming potential: ability of a gas to trap thermal energy in the atmosphere over time.

Persistence: length of time the gas remains in the atm.

Greenland Ice Core Project:-Each snowfall compounds ice beneath and samples taken (3092 m ice core drilled) tells us atm. Gases in bubbles and thickness of ice.- this evidence along with other data show inc. in greenhouse gases since 1700’s

Anthropogenic greenhouse effect:Additional greenhouse gases from human activities.

Sources:

Greenhouse Gas

Sources

CO2 -Burning coal, gas, oil and natural gas-Cement making-Deforestation

CH4 -Coal mining-Production of petroleum products- natural gas leaks-Rice paddies, landfills, cattle

N2O -Burning coal, oil, gasoline, and natural gas- fertilizer

Carbon Sink: photosynthesis – removes CO2 from atm. and stores it.The balance between carbon sinks and carbon sources has been shifted since the Industrial Revolution. Inc. of 28% over last 200 yrs.

Global Warming: observed inc. in Earth’s avg. annual temp.

Climate Change: as a result of global warming and is the significant long-term change in expected climate patterns.

- includes # and severity of storms, wind strength, precipitation, floods and droughts etc.

Human Activities that produce Greenhouse Gas emissions:

- Varies from province to province and between nations.

Effects of Climate Change on the atm.:

1. Heat Waves

2. Drought: regions near desert. Ex: Ethopia = inadequate food

3. Wildfires: Southern California, Australia, BC

4. Storms: Ice storm in 1998

5. Floods

Effects of Climate Change in the Hydrosphere:

1. Melting Ice:-sea and glacier ice are melting- flood land that is just above sea level- habitat changes- loss of property- changing geographic coastlines/shapes of coasts- reduce amt. of fresh water available

Three causes:1.Warm water expands2.Glaciers on land have retreated3.Greenland and Antarctic continental glaciers have been melting.

2. Ocean Warming:-Thermal expansion = higher sea levels-Warmer water absorbs less CO2, produces more intense hurricanes and has less plankton growth

Ocean Currents

-Earth’s heating and cooling circulation system- Ice – frozen FRESH water, so as glaciers melt, oceans are more dilute = less salinity. Less salinity = less dense and affects the ocean currents.

Effects of Climate Change on Wildlife

Ex: inc. ocean temp = decrease in Pacific Salmon

1.Range Shifts: Ranges of many animals have moved northward due to warming temperatures. Opossums, Black-legged ticks and Southern Gray jays.

2.Threatened Species: 40 – 70% of all species are at risk of extinction if the global avg. temp increases by only 3.3 C. Earth has lost ~20% of it’s coral reefs due to warmer water, sedimentation, and storm damage.

- Acidity inc. in sea water increases as oceans absorb ~25% of all CO2 emissions and this can damage shells of clams, snails etc.

- Commercial fish stocks

Organisms That Benefit From Climate Change

-free-living jellyfishes have increased ~100 x’s

Effects of Climate Change on Economy

Economic System: how goods are produced, distributed and consumed.

-Since industrial revolution people have shifted away from doing things themselves to purchasing food, clothing etc.- transportation, manufacturing, etc. use fossil fuels.- Food production – people are choosing locally instead.

Effects of Climate Change on Societies

-Developed countries have much larger greenhouse gas emissions than developing countries- Table 8.4 on pg. 324 shows ranking of various countries- Developing countries are more at risk for extreme climates, less prepared.- Food, drinkable water, infrastructure breakdown, disease, and population displacement are some impacts of climate change.

GLOBAL CONSEQUENCES- Positive feedback loop: sequence of events where one action cycles back to earlier event and enhances it

Ex: wildfire destroys forest (less CO2 absorption) and increase in greenhouse effect = warmer temp. = more wildfires

How is ice melting and example of this?? (hint: albedo effect)

Are there any positive effects?

-Length of growing season in Ont. Is longer.- Northwest passage has melted and ships can travel through

What are Governments Doing?

Kyoto Protocol

• 1997, Canada and 160 other countries agreed to reduce emissions by 5% by 2012. • Agreement went into effect in 2005 and by 2008, 183 countries had ratified.• Includes credit system:

• if help a developing country reduce it’s emissions• developed country helps another developed country in time of crisis• planting trees etc.

•Some see as a way for richer countries to get out of reducing their emissions• USA has neither ratified nor withdrawn • In July 2008, G8 leaders agreed to halve the emmisions by 2050 – how?

Table 9.2 on pg. 345 outlines Gas Emission targets by Jurisdiction in Canada.

What Can We Do?

-We must mitigate climate change by:1.Reduce overall energy use, use alternative energy2.Industrial gases must be removed and sequestered

Both will reduce our CARBON FOOTPRINT

-Reduce electricity use-Reduce Fossil Fuel Consumption (heat and transportation). H powered cars? -Sequestering CO2 (capture gases and store underground but risks, costs unknown).-Carbon offsets: individuals can purchase - $$ used for replanting forests, research etc.-Emissions Trading: companies exceeding their emissions can trade with other companies-Carbon Tax: pollution tax Ex: BC gov’t

How Can YOU reduce your carbon footprint???