Transcript Global_climate_Change-wiki - MM

Earth’s Atmosphere and Climate
Big Question
Global Warming Is Happening: What Part Do We Play?
Overview to Climate Change
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Collecting data
Climate vs WeatherCauses of Global Climate Change
Effects of Climate Change
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Melting Ice and Rising Sea Level
Changes in Precipitation Patterns
Effects on Organisms
Effects on Human Health
Effects on Agriculture
• Dealing with Global Climate Change
How do we get our data?
• Taking the Earth's Temperature
– http://www.teachersdomain.org/resource/tdc02.sci.life.eco.earthstemp/
• Proxy Data- 6 Clues from Past Climates
– http://www.teachersdomain.org/assets/thinktv/ttv10/ttv10_int_clues/index.html
Is the Global Temperature Rising?
• Yes, and it is rising
globally
• Is global the same as
local ?
• NO! This is the same
as the difference
between weather and
climate.Let’s look: Small groups
http://www.youtube.com/watch?v=wUiwtVSkUwQ
• Has the temperature
risen steadily?
• In the last 100 years, the global average annual
temperature has risen approximately 0.6°C
• It has also gotten warmer faster
• The overall picture supports the view that global
warming is occurring
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http://data.giss.nasa.gov/gistemp/graphs/
What Causes Climate Change and
What Is Making It Get Warmer?
The answer is complex and a variety of sources determine it.
Honors: http://www.teachersdomain.org/resource/ess05.sci.ess.watcyc.climatechange/
• Albedo: the
percentage of
light received by
a surface that is
reflected and
scattered
Variation in the Sun’s Energy May Be
A Reason for Climate Changes
• The sun’s energy seems to have varied
over the ages.
Milankovich Cycles:
Another Possible Explanation
• Some temperature cycles
stem from changes in Earth’s
orbit.
 D Eccentricity- D orbit ellipse
 D Tilt in axis
 D Precession- D wobbledetermines major change in
seasons
http://www.wwnorton.com/college/geo/egeo/flash/18_2.swf
ttp://itg1.meteor.wisc.edu/wxwise/climate/earthorbit.html
Precession
Volcanoes Can Alter Climate
• Volcanic eruptions cool the
climate in two ways:
- Atmospheric dust reflects
sunlight back into space
- Smaller dust particles
provide water condensing
surfaces, forming clouds
Dust from Our Own Activities Also
Cools the Climate
• Aerosol pollution particles reduce amount of
sunlight reaching Earth
• Emissions have reduced global warming
Variations in Ocean Currents May
Affect the Climate
• Ocean currents and prevailing winds warm or
cool our planet
• The Gulf Stream: a major ocean circulation
affecting climate
El Niño
A Climate Phenomenon Linked to
Ocean Currents
(Christ Child)
• A climate change linked to variations in ocean
currents accompanied by Southern Oscillation,
changes in air pressure.
• Prevents upwellings- the transport of deeper
water to shallow levels cool surface water and
supports bird and fish populations
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http://ww2010.atmos.uiuc.edu/(Gl)/guides/mtr/eln/upw.rxml
• El Niño is important for two reasons:
– It is a global event
– It is likely to become more common and more intense
• Yet, the initial cause of El Niño is unknown
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Temp event
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensocycle/ensocycle.shtml
Precipitations event
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensocycle/elninosfc.shtml
Lab-
• Some of it lies in the Earth’s energy balance between
the amount of energy coming in from the sun and the
amount of energy radiated out by the Earth
http://www.ncdc.noaa.gov/paleo/ctl/overview.html
The Greenhouse Effect, and How It
Warms Earth’s Surface
• Earth’s surface temperature determined by
four main factors:
1. Amount of sunlight Earth receives
2. Amount of sunlight Earth reflects
3. Retention of heat by atmosphere
4. Evaporation and condensation of water vapor
Greenhouse gases
• are particularly good at absorbing infrared
radiation
• Include water vapor, carbon dioxide, methane,
nitrogen oxides, ozone and
chlorofluorocarbons (CFCs)
• Greenhouse gases trap heat much as panes of
glass do in a greenhouse
• A small amount of gas has a big effect on
temperature
• Gases produce a greenhouse effect on other
planets too
• The enhanced greenhouse effect keeps Earth
warmer than it would otherwise be
Greenhouse Gases Are Increasing
• We are part of the reason
• Carbon dioxide has been increasing in the
atmosphere for some time
• First suggested early in the
19th century
• 1957: an observatory
established on Mauna Loa
Volcano, Hawaii
• Scientists estimate the CO2
• concentration in ancient
atmosphere using air
bubbles trapped in polar ice
sheets
http://www.esrl.noaa.gov/gmd/ccgg/trends/
Anthropogenic Changes
• People add to atmospheric carbon dioxide by :
- Burning fossil fuels and wood
- Major changes in land use, i.e. cutting
down forests and removing prairies
http://www.gapminder.org/
Methane
• Concentration doubled in past 200 years.
• More potent than CO2
• People can add methane to atmospheric by :
– Removing fossil fuels
– Increasing number of domesticated ruminants
(cows, etc.)
– Destroying wetlands (releases stored methane)
– Increasing the size of landfills and stored organic
matter
– Increasing habitats where methane-producing
bacteria live
• ( polar) http://www.youtube.com/watch?v=Wofv9o0j1Ew
Would It Really Be So Serious
If Earth Warmed Up a Bit?
• Possible Effects from Global Warming
• Steps to forecasting effects:
1. Forecast changes in climate and physical
conditions of the oceans and land surfaces
2. Forecast species and ecosystems response
• Computer models are the major scientific tool
• Model results: Global warming will increase Earth’s
surface temperature by 1 to 5°C from 1990 to 2100
• Forecasts suggest that temperatures will continue to
rise- Where in the world is the greatest change?
Changing Precipitation Patterns
• Some areas will get more water, some areas
will have greater droughts
– Ex: Hurricanes will likely get stronger
Amount of
change in
precipitation
Impacts in Fragile Areas
• Eskimo Inuit live traditional
life dictated by freezing
climate
• Climate change is altering
their existence
– Wildlife are smaller or displaced
– Reduced snow cover and shorter
river ice seasons
– Thawing of permafrost (right)
– What is permafrost?
Damage from Melting Permafrost
F. Nelson
http://nsidc.org/sotc/per
mafrost.html
Cherskii, Siberia
Fairbanks, AK
http://www.flickr.com/photos/73423050@N00/912440368/
http://www.klimanotizen.de/html/newsletter_14e.html
Permafrost
damage in
Fairbanks,
AK and Tibet
http://www.globalwarmingimages.net/gallery/index/disp_media/429/gallery/pe
rma_frost/0/
“Thawing permafrost can render
railroad tracks useless, as seen in this
photo from the northern Tibetan Plateau
taken in the early 1960s.” Credit: Tingjun Zhang
http://www.livescience.com/environment/041222_permafrost.html
CH4
CH4
CH4
CH4
CH4
CH4
CH4
Karen Frey; image
CH4
Changes in Arctic Culture
• Loss of permafrost
and Loss of
traditional culture
causes depression
and increased suicide
rate: Prevention
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http://umassk12.net/ipy/materials/2009Sum
mer/wexler/17yearswexler/index.html
Melting Ice and Rising Sea Levels
1957
1998
Rising Sea Level
• Risen naturally since last ice age, yet rate
increasing
LAB Activity
Effects on Organisms - Coral Reefs
• Coral reefs can be bleached (right) due to
increase in water temperature
– makes them more susceptible to diseases to which
they would otherwise be immune
Effects of Global Climate Change- Effects on
Organisms
• Zooplankton in parts of California Current
have decreased by 80% since 1951
– Effecting entire food chain
• Decline in krill around Antarctica
– Caused decrease in penguin populations
• Species have shifted their geographic range
• Migrating birds are returning to summer
homes earlier
– Food is not available at this time
Species Migration
Spreads
Diseases
• Example: Changing
range of disease
carrying mosquitoes
West Nile virus is an example of global
warming spreading disease:
1. Mild winters -more mosquitoes 2. Dry springs increase - mosquito and bird
concentrations
3. Mosquitoes with virus bite uninfected birds
4. Infected birds are bitten by uninfected
mosquitoes, passing the virus to them
5. Hot, wet summers cause mosquito population to
mature and grow rapidly
Effects on Human Health
• Increased number of heat-related illnesses and
deaths
Dealing with Global Climate Change
• To avoid the worst of climate change, CO2
levels must be stabilized at 550ppm
– 50% higher than current levels
• Two ways to attempt to manage climate
change
– Mitigation
• Reduce production and release of greenhouse gases
• Find ways to sequester (store) greenhouse gases
– Adaptation
• Focuses on learning to live with to the environmental
changes and societal consequences brought about by
global climate change
Politics/policy on Global Warming
• Toronto 1988: scientists recommended a 20%
reduction in carbon dioxide emissions by 2005
• Earth Summit 1992: Blueprint for reducing
global emissions
• Kyoto 1997: Legally binding emission limits
• We have run out of excuses
• What is being done in the United States?
• Why is the Kyoto Accord so important?
Alleviating the Effects of
Global WarmingWhat else can we do?
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Move species to new habitats
Establish new nature preserves
Establish wildlife corridors
Develop new strains of improved-yield crops
Learn to live with the changes
• http://www.youtube.com/watch?v=08z-Hw7s54E