Download Effects of Climate Change on Societies

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. Tundra
2. Boreal Forest
3. Temperate Deciduous Forest
4. Temperate Grassland
5. Temperate Coniferous Forest
6. Mountains
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.
Layer
Troposphere
Stratosphere
Mesosphere
Thermosphere
Average
Altitude from
Earth’s
surface (km)
Temperature
range (C)
Characteristics
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 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 expands
2. Glaciers on land have retreated
3. 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 energy
2. 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???