Download Climate Change

Global Environmental Change
Climate Change, Global
Warming…
…what’s going on?
What is Climate?
• Climate = the average and variations of
weather over a long period of time (~30 years)
Above: Global average for atmospheric water vapor.
What is Weather?
• Weather = all natural phenonmena
within the atmosphere at a given
time (hours to days)
The Climate System
Oceans
Atmosphere
Ice
Biosphere
Land
• The Earth has
many different
systems that
interact with each
other in different
ways.
Modern Climate Systems
• Atmospheric circulation
Sunlight
Modern Climate Systems
• Atmospheric circulation
P.C.
F.C.
H.C.
Modern Climate Systems
• Ocean circulation
Sinking cool water,
rising warm water
and wind help to
form global ocean
current systems.
The Great Ocean Conveyor
Modern Climate Systems
• Atmosphere and Greenhouse Effect
– The Earth’s atmosphere keeps it around
30°C warmer than it would otherwise be.
– This is the Greenhouse Effect
What is the Greenhouse Effect?
cc. Robert A. Rohde (Global Warming Art)
cc. Robert A. Rohde (Global Warming Art)
The temperature of the Earth
depends on the amount of energy we
receive from the sun versus the
amount of energy lost back out to
space.
The Carbon Cycle
Past Climate Systems
• How do we know about climate systems
in the past?
Past Climate Systems
1. Early human record
cc. W.V. Bailey
Rock paintings provide evidence of
fertile Sahara region (now desert)
6,000 years ago.
Tourism NT http://www.travelnt.com
Past Climate Systems
2. Geomorphology
River deltas
show where
rivers entered
the ocean or a
lake.
Above: A “U” shaped valley
shows that it was formed by
a glacier.
Past Climate Systems
3. Geological record
Fossils preserve evidence of past life.
Drilling into the ground can recover rock
layers that record what conditions were
like when the rock was deposited.
Past Climate Systems
4. Ice cores
Ice cores can preserve
seasonal layering.
Studying the chemistry of
each layer can give clues
about climate change.
GISP2 ice core at 1837m depth with clearly visible annual layers.
Is the Climate Changing?
https://www.ted.com/talks/gavin_schmidt_the
_emergent_patterns_of_climate_change
What is Climate Change?
• The variation in the Earth's
global climate or in regional
climates over time.
What are the current climate trends?
Global temperature for the
last 150 years
cc. Robert A. Rohde http://www.globalwarmingart.com/wiki/Image:Instrumental_Temperature_Record_png
What are the current climate trends?
cc. Robert A. Rohde http://www.globalwarmingart.com/wiki/Image:Global_Warming_Map_jpg
Looking further into the past…
Global temperature for the
last 1000 years
cc. Robert A. Rohde http://www.globalwarmingart.com/wiki/Image:1000_Year_Temperature_Comparison_png
Looking further into the past…
Global temperature for the
last 450,000 years
cc. Robert A. Rohde http://www.globalwarmingart.com/wiki/Image:Ice_Age_Temperature_Rev_png
Anthropogenic Influence
• Fossil fuel
• Aerosols
• Cement
manufacture
• Land use
• Livestock
cc. Robert A. Rohde
http://www.globalwarmingart.com/wiki/Image:Carbon_Dioxide_400kyr.png
Fossil Fuels:
• Beginning with the industrial revolution in the 1850s
and accelerating ever since, the human consumption
of fossil fuels has elevated CO2 levels from a
concentration of ~280 ppm (parts per million) in the
atmosphere to more than 380 ppm today.
• These increases are projected to reach more than 560
ppm before the end of the 21st century. It is known
that carbon dioxide levels are substantially higher now
than at any time in the last 800,000 years. Along with
rising methane levels, these changes are anticipated
to cause an increase of 1.4-5.6°C between 1990 and
2100.
Aerosols
• Anthropogenic aerosols, particularly
sulphate aerosols from fossil fuel
combustion, are believed to exert a cooling
influence. This, together with natural
variability, is believed to account for the
relative "plateau" in the graph of 20th
century temperatures in the middle of the
century.
Cement Manufacture:
• Cement manufacturing is the third largest
cause of man-made carbon dioxide
emissions. While fossil fuel combustion and
deforestation each produce significantly
more carbon dioxide (CO2), cement-making
is responsible for approximately 2.5% of
total worldwide emissions from industrial
sources (energy plus manufacturing
sectors).
Land Use:
• Prior to widespread fossil fuel use,
humanity's largest effect on local climate is
likely to have resulted from land use. For
example, irrigation, deforestation, and
agriculture change the amount of water
going into and out of a given location.
Livestock:
• According to a 2006 United Nations report, livestock is responsible
for 18% of the world’s greenhouse gas emissions as measured in
CO2 equivalents.
• This however includes land usage change, meaning deforestation
in order to create grazing land. In the Amazon, 70% of deforestation
is to make way for grazing land, so this is the major factor in the
2006 UN FAO report, which was the first agricultural report to
include land usage change into the radiative forcing of livestock. In
addition to CO2 emissions, livestock produces 65% of humaninduced nitrous oxide (which has 296 times the global warming
potential of CO2) and 37% of human-induced methane (which has
23 times the global warming potential of CO2).
Are There Other Causes?
• Natural Impacts:
*Change in sun’s
energy output
*Volcanoes
*clouds
*Water vapor
Milankovitch cycles influence climate
• Milankovitch cycles = periodic
changes in Earth’s rotation and
orbit around the sun
– Alter the way solar radiation is
distributed over Earth
• These cycles modify patterns of
atmospheric heating
– Triggering climate variation
– For example, periods of cold
glaciation and warm
interglacial times
Future predictions…
• Based on no
changes in
emissions
(“business as
usual”) the
Earth would
be 3 degrees
C hotter on
average.
cc. Robert A. Rohde http://www.globalwarmingart.com/wiki/Image:Global_Warming_Predictions_Map_jpg
What does it all mean?
• Sea level rise
• More extreme
weather
• Changes in
precipitation
• Spread of
disease
cc. Robert A. Rohde
http://www.globalwarmingart.com/wiki/Image:Recent_Sea_Level_Rise_png
Rising sea levels
• Runoff from melting glaciers and ice will cause sea
levels to rise
• As oceans warm, they expand
– Leading to beach erosion, coastal floods, and
intrusion of salt water into aquifers
Projected changes in precipitation
Precipitation will increase at high
latitudes and decrease at low and
middle latitudes
Coastal areas will flood
• Storm surge = temporary, localized rise in sea level
– Caused by the high tides and winds of storms
• Cities will be flooded
– 53% of people in the U.S. live in coastal areas
Melting snow and ice
• Mountaintop glaciers are disappearing
– Glaciers on tropical mountaintops have disappeared
– The remaining 26 of 150 glaciers in Glacier National
Park will be gone by 2020 or 2030
– Reducing summertime water supplies
• Melting of Greenland’s Arctic ice sheet is accelerating
• Warmer water is melting Antarctic coastal ice shelves
– Interior snow is increasing due to more precipitation
• Melting ice exposes darker, less-reflective surfaces, which
absorb more sunlight, causing more melting
Coral reefs are threatened
• Coral reefs are habitat for food fish
– Snorkeling and scuba diving sites for tourism
• Warmer waters contribute to coral bleaching
– Which kills corals
• Increased CO2 is acidifying the ocean
– Organisms can’t build their exoskeletons
• Oceans have already decreased by 0.1 pH unit
– Enough to kill most coral reefs
Climate change affects organisms and
ecosystems
• Organisms are adapted to their environments
– They are affected when those environments change
• Global warming modifies temperature-dependent
phenomena (e.g., timing of migration, breeding)
• Animals and plants will move toward the poles or upward in
elevation
– 20–30% of species will be threatened with extinction
– Rare species will be pushed out of preserves
• Droughts, fire, and disease will decrease plant growth
– Fewer plants means more CO2 in the atmosphere
Climate change affects people
• Societies are feeling the impacts of climate change
• Agriculture: shortened growing seasons, decreased
production, crops more susceptible to droughts
– Increasing hunger
• Forestry: increased fires, invasive species
– Insect and disease outbreaks
• Health: heat waves and stress can cause death
– Respiratory ailments, expansion of tropical diseases
– Disease and sanitation problems from flooding
– Drowning from storms
Impacts of climate change will vary
Predictions from two climate models
By 2050, Illinois will have a
climate like Missouri’s
By 2090, it will have a
climate like Louisiana’s
Causes and consequences of climate change
The FCCC
• U.N. Framework Convention on Climate
• Change = a plan to reduce greenhouse gas emissions to
1990 levels by 2000 through a voluntary, nation-by-nation
approach
• By the late 1990s, it was clear that the voluntary approach
would not succeed
• Developing nations created a binding international treaty
requiring emission reductions
Intergovernmental Panel on Climate
Change (IPCC) was established in 1988
- Composed of hundreds of international
scientists and government officials
- reports on the synthesis of scientific
information concerning climate change
• Global consensus of scientific climate research
• Summarized thousands of studies
The IPCC’s fourth assessment report (2007)
• Documented observed trends in surface
temperature, precipitation patterns, snow
and ice cover, sea levels, storm intensity,
etc.
• Predicted impacts of current and future
climate change on wildlife, ecosystems, and
human societies
• Discussed strategies to pursue in response
to climate change
The IPCC’s fourth assessment report (2007)
emissions
Kyoto Protocol
• Mandates signatory nations, by the period 2008-2012 , to
reduce emissions of six greenhouse gases to levels below
those of 1990.
• This treaty took effect in 2005
• Russia became the 127th nation to ratify it
• The United States will not ratify the Kyoto Protocol
• It requires industrialized nations to reduce emissions
• But it does not require industrializing nations (China and
India) to reduce theirs
• Other countries resent the U.S. because it emits 20% of the
world’s greenhouse gases but won’t take action
• In 2007, one delegate said, “If for some reason you are
not willing to lead...please get out of the way.”
The Copenhagen Conference
• The conference in 2009 tried to design a successor treaty to
the Kyoto Protocol
– Nations hoped the U.S., under President Obama, would
participate in a full international agreement
• Obama would not promise more than Congress had agreed
to
• In a last-minute deal, developed nations will help developing
nations pay for mitigation and adaptation
– Nations that reduce deforestation will be rewarded
• Nothing is legally binding and no targets are set
Electricity Generation
A coal-fired, electricitygenerating power plant
• The largest source of U.S. CO2 emissions
– 70% of electricity comes from fossil fuels
– Coal causes 50% of emissions
• To reduce fossil fuel use:
– Encourage conservation and efficiency
– Switch to cleaner and renewable energy sources
Conservation and efficiency
• We can make lifestyle choices to reduce electricity use
– Use fewer greenhouse-gas-producing appliances
– Use electricity more efficiently
• The EPA’s Energy Star Program rates appliances, lights,
windows, etc. by their energy efficiency
– Replace old appliances with efficient ones
– Use compact fluorescent lights
– Use efficient windows, ducts, insulation, heating and
cooling systems
Sources of electricity
• We need to switch to clean energy sources
– Nuclear power, biomass energy, solar, wind, etc.
• We need to consider how we use fossil fuels
– Switching from coal to natural gas cuts emissions 50%
– Cogeneration produces fewer emissions
• Carbon capture = removes CO2 from power plant emissions
• Carbon sequestration (storage) = storing carbon
underground where it will not seep out
– Use depleted oil and gas deposits, salt mines, etc.
– We can’t store enough CO2 to make a difference
Transportation
• 2nd largest source of U.S.
greenhouse gases
– Cars are inefficient
• Ways to help:
– More efficient cars
– Hybrid or electric cars
– Drive less and use
public transportation
– Live near your job, so
you can bike or walk
U.S. public transportation
saves 4.2 billion gallons of
gasoline and 37 million metric
tons of CO2 emissions
Conventional cars are
inefficient
We can reduce emissions in other ways
• Agriculture: sustainable land management lets soil store
more carbon
• Reduce methane emissions from rice and cattle
• Grow renewable biofuels
• Forestry: reforest cleared land, preserve existing forests
• Sustainable forestry practices
• Waste management: treating wastewater
• Generating electricity by incinerating waste
• Recovering methane from landfills
• Individuals can recycle, compost, reduce, or reuse goods
Market mechanisms address climate change
• Permit trading programs harness the economic efficiency of the free
market to achieve policy goals
– Businesses have flexibility in how they meet the goals
• Polluters choose how to cut their emissions
– They are given financial incentives to reduce them
Boiling Frog Syndrome
Questions to be answered…
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How fast will the sea level rise?
How much warmer will it get?
When will the Arctic Ocean be ice-free?
Will the water cycle accelerate?
Are climate extremes increasing?
Will there be abrupt changes?
Shall we pursue mitigation or adaptation?
• Most people accept that our planet is changing
– They are searching for solutions
• Mitigation = pursue actions that reduce greenhouse gas
emissions to lessen severity of future climate change
– Energy efficiency, renewable energy, protecting soil,
preventing deforestation
• Adaptation = accept that climate change is happening
– Pursue strategies to minimize its impacts on us
– Seawalls, leaving the area, coping with drought, etc.
• Both are necessary
Science can provide
knowledge…
…We all have to
provide the solutions.
Climate Change: What can I
do?
In your group, write down as many ways
to save energy and become “greener” that
you can think of. Get one member of each
group to present their ideas.