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Global Climate Change

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by

Ms. Farrell

on 27 January 2018

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Transcript of Global Climate Change

The melting of the ice caps
Global Warming
Emissions of CO2
In 2009, developing countries surpassed developed countries in terms of CO2 emissions
Development in China & India has been rapid
China is leading emitter of CO2
China: 21% of global CO2
US: 19% of global CO2
Evidence of Global Warming
The IPCC:
Intergovernmental Panel on Climate Change
>3,000 scientists studying climate change
Evidence From Earth's Past
How can we tell about the earth's temp in the past?
No one was measuring temp 400,000 years ago!
Global Warming
Humans are Changing the Planet
Increased demand on natural resources
water
trees
minerals
fossil fuels
emitting great amounts air pollutants
CO2
NOx
SO2
VOCs
Agriculture
fertilizers
pesticides
Manure lagoons
Waste Generation
disposal
sanitation
spread of diseases
Global Change
Global Climate Change
One specific type of Global Change is "Global Climate Change"
refers to:
increased storm intensity
Altered patterns of precipitation and temperature
Altered patterns of ocean circulation
Is a result of Global Warming:
The warming of the planet's air, land, and water
Increased heat waves
reduced cold spells
1. Incoming Solar Radiation
consists primarily of UV and visible light
The Greenhouse Effect
2. About 1/3 of this solar radiation is deflected back into space
3. The Remaining solar radiation is absorbed by the surface of the planet. The planet warms and then releases
infrared radiation

5. Much of the infrared radiation is absorbed by greenhouse gasses
Some of the infrared is emitted into space
CO2
H2O
CH4
CH4
CH4
CO2
CO2
CO2
CO2
H2O
H2O
H2O
H2O
5. The more greenhouse gasses, the more infrared absorbed
The more infrared absorbed, the warmer the atmosphere
N20
N2O
N2O
O3
O3
O3
O3
Greenhouse Gasses
Potency of the greenhouse gas depends on two factors:
2. How long it can stay in the atmosphere
H2O
Global Warming Potential: <1
Duration in atmosphere: 9 days
CO2
GWP: 1
Duration in Atmosphere: 1-100yrs
Methane
GWP: 25
Duration in atmosphere: 12 years
N2O
GWP: 300
Duration in atmosphere: 114 yrs
CFCs
GWP: 1,600-13,000
Duration in Atmosphere: 55-500 years
Anthropogenic sources of Greenhouse Gasses
Methane:
1. Livestock Digestion
2. Landfills
3. Natural gas and petroleum
Nitrous Oxides:
1. Agricultural soils
Carbon Dioxide
1. Fossil Fuels
2. Iron and Steel Production
Beginning of the 20th century, scientist did not believe CO2 contributed to global warming
Too little CO2 in the atmosphere to make much of a difference
Difficult to measure
Enter Charles David Keeling--> first to overcome the technical difficulties measuring atmospheric CO2
CO2 concentrations vary seasonally
Deciduous trees in spring increase photosynthesis, bringing down atmospheric CO2
A clear trend showing increasing CO2
Who Studies this stuff?
NOAA: National Oceanic and Atmospheric Administration
http://image.guardian.co.uk/sys-files/Guardian/documents/2011/02/10/CarbonWeb.pdf
Is CO2 making earth warmer?
NASA has measured a global temp increase of about 1.4 F
9 warmest years ever recorded have occurred between 1998-2012
There is no doubt that the earth is warming, but is this just a natural phenomenon?
must look deeper into earth's past to know for sure
1. Foraminifera: Aquatic protists
Each species of foraminifera con tolerate only certain environments
Made of CaCo3
Determining ratio of O to C also gives clues of the environment
2. Ice Cores
Samples of ice cores have tiny bubbles in them
these bubbles consist of the atmospheric composition from thousands of years ago
also look at Oxygen isotopes.
O^18 is in higher concentrations during colder time periods
CO2 Concentrations and Ocean Temperatures
Scientists use models to replicate previous known temps and CO2 concentrations
Global Warming Consequences
Polar Ice Caps
Arctic has already warmed 1.8-7.2 F
Likely to warm another 7-13 F
Creating large openings in the ice
Loss of ice = loss of albedo

ice reflects more radiation with less ice, more heat is absorbed by the ocean, further heating the planet
Trapped methane under ice caps
Estimates: 70-390 billion tons of methane
If that escapes....
Glaciers
Glacier National Park in Northwest Montana
1850: 150 glaciers
2013: less than 25
Glaciers an important source of freshwater
melt partially in the spring, regrow in the winter
now melting faster than they can regrow
Permafrost melting
Permafrost: A permanently frozen layer of soil
tundra and boreal forest
Can cause:
lake draining
problems with human-built structures
ground can slide away!decomposition will occur under wet soil, low oxygen
release methane
Sea Levels
1. Melting of glaciers increases total volume of water
2. As water warms, it expands
Sea level has risen 220 mm since 1870 (9 inches)
by the end of the 21st century, could rise another 180-590 mm (7-23 inches)
Heat Waves
Long periods of heat waves are to become more frequent
increased energy demand for cooling
increased risk of death
damage crops, greater need for irrigation
Raise cost of food production
Cold Spells
Minimum temperatures expected to increase over most areas

Pros:
fewer deaths due to cold temperatures
decrease in the risk of crop damage
new areas available for agriculture
decrease the energy needed to ehat buildings in the winter
Cons:
prevent death of pests
Precipitation Patterns
Increased evaporation due to warmer climate
difficulty predicting rain patterns through models
some may experience increased rainfall, differ in predicting which regions
may help with agriculture
could also increase
runoff
flooding
landslide
soil erosion
While some get more water, others may get less
greater efforts to supply water with crops
Storm Intensity
Impossible to link any weather event with global warming
too many variables involved
Hurricanes Katrina and Rita
Storm intensity due to Gulf of Mexico being unusually warm
Scientist believe that 50% of that warmth due to global warming
Studies show that Atlantic hurricanes have doubled in the past century
Ocean Currents
Increase in temp may cause a shift to ocean currents
4.
CFCs
CFCs
CFCs
CFCs
CFCs
1. How much infrared it can absorb (Global Warming Potential)
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