Transcript Global Warming - staeger science

Environmental
Systems
Assessment statements 6.1.1-6.1.7
The issue of Global warming
6.1.1 Describe the role of greenhouse gasses
• Carbon Dioxide is a major Greenhouse Gas
• Other gasses: methane, nitrous oxide, tropospheric
ozone, CFCs, and water vapor.
• Under natural conditions these gasses absorb heat
and keep the earth’s temp at a range that can support
life.
• The Greenhouse effect is normal & necessary
condition for life on earth. If it were not for these
gasses, earth’s temperature would be 35°C or 63°F
colder than it is now.
Greenhouse Effect: a natural process
that traps heat near the Earth’s surface.
• short wave
radiation in
• long wave
radiation out
• re-radiation
downward by
“greenhouse
gases” in
atmosphere
6.1.2- Ways in which humans
add to greenhouse gasses
• 1. Burning Fossil Fuels
• 2. Deforestation
• 3. Rice and Cattle Farming
One fifth of global Methane
emissions (by humans) b/c of
wetland rice paddies (the largest of
man-made methane sources).
Human Inputs
a) CO2
• carbon dioxide (CO2)
– 67% from top 10
countries
• China = 21.5% of total
• US = 20.2% of total
• China’s per capita = 4.62
• US’s per capita = 18.99
• Largest per capita?
– 56.24…..Qatar….Why?
• chlorofluorocarbons
b) CFCs
Human
inputs
c) CH4
(continued)
•methane
(CH4)
•nitrous oxide
(N2O)
d) N2O
Fig. 19–2 c & d
Has the concentration of
atmospheric carbon
dioxide changed?
Mauna Loa, Hawaii
Has the concentration of
atmospheric carbon
dioxide changed?
Cape Grim, Tasmania
Global Warming?
Are the two linked?
Climate
During Past
160,000 Years
• End of last ice age
about 10,000 ago
• Now in warm
interglacial period
• During the last ice age,
the earth was on
average only 3-5oC
colder than today.
Fig. 19–4
What is the Scientific Consensus?
• Mean global temperature
rose about 0.6º C (1º F) in
past 100 years
• Increase is real, not
explained by natural
variation in solar radiation
• Warming greater at poles
than equator
• Likely future scenario:
doubling of CO2 (from
280 ppm to 560 ppm)
before 2100 leading
to an additional 2ºCFig. 19–5
6.1.3 Qualitative effects on mean global
temperature increase.
1. Melt polar icecaps & glaciers causing rise in sea levels.
Coastal cities could be wiped out.
2. This will cause relocation or disappearance of temperate
& desert biomes because of weather changes = ?
3. Crop losses and alterations in crop growing seasons due to
increased flooding and weather.
4. Local - Chesapeake bay fisherman will suffer reduced
oyster harvest due to increased salinity. Increased
temperature increases bacterial infections of oysters.
Consequences of increased G. Gasses
Consequences of a global
temperature rise on
artic ecosystems
Increased
Decomposition
of detritus in
Permafrost
This releases
methane into the
atmosphere!
Feedback loop?
Global Warming?
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1920: Photograph by unknown
photographer in the collection of the
National Snow and Ice Data
Center/World Data Center for
Glaciology. Public domain by virtue
of age. [1]
August 8th, 2005: Photograph by
Bruce F. Molnia of the USGS, in the
collection of the National Snow and
Ice Data Center/World Data Center
for Glaciology. Public domain as a
work of the US government. [2]
Glacier Bay National Park, Alaska
Consequences of a global
temperature rise on arctic
ecosystems
Expansion of habitats
available for
temperate species
Glacier Bay National Park, Alaska
Consequences of a global
temperature rise on
arctic ecosystems
Loss of ice habitat
Consequences of a global
temperature rise on
arctic ecosystems
• Changes in producers
and prey that other
trophic levels rely on
• Increased success of
pest, including
pathogens
Consequences of a global
temperature rise on
freshwater supply
• Increased Evaporation
• Increased Precipitation in dry areas and possible
Decrease Precipitation in normally wet areas
– This can change river flows
– Monsoons and Hurricanes could increase in intensity
– Thermal expansion of Oceans as Polar ice caps and glaciers
melt
• This can cause the mixing of salt and fresh water supplies!
• How will this affect our freshwater supplies?
Feedback?
• What are some positive feedbacks in Global
Warming?
• What are some negative feedbacks in
Global Warming?
• Time lags?
6.1.5 - Ways to reduce G. gasses
Locally
1. Walk, ride bike, carpool, mass transit
2. Replace standard light bulbs with fluorescents and worn
out appliances with energy efficient models
3. Wrap your water heater - insulate house
4. Ask utility co. for a home energy audit to pinpoint
energy wasters
5. Stopping slash and burn agricultural methods
6. Use alternative energies
7. Buy hybrid or electric cars
8. Use types of rice that can be grown under much drier
conditions.
Globally…Regulate
1.
“Kyoto Protocol” – First met in 1997 in Kyoto Japan 160
nations agreed to cutback emissions of CO2, NO2 & CH4
6% below 1990 levels. (No penalties discussed) (multiple
amendments have been made…US has not signed)
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An international agreement linked to the United Nations Framework Convention on
Climate Change
The Protocol places a heavier burden on developed nations under the principle of
"common but differentiated responsibilities."
IPCC (Intergovernmental Panel on Climate Change) advises the decisions at the
convention
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4.
IPCC set up by UN; 830 scientists, authors, and editors from 85 countries
They assess the Physical Science Basis, Impacts, Adaptations and Vulnerability, and Mitigation
of Climate Change
Write a summary report – last one called the Fifth Assessment Report (AR5) was finalized in
October 2014
Emission Trading – Allow industries/countries that violate
quotas to purchase the “extra emissions” from other
industries/countries that beat their assigned reductions. Also
new forest offset emission. (US Proposed this)
Government mandated change from coal to oil to natural
gas to alternative energy sources.
Carbon Tax
Restore…reactive
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Restoration of forests
Irrigation of once temperate lands
Desalinization of ocean water
Build water levies for flooded coastal areas
What can we do?