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Ch 19 Climate Change and Ozone Depletion
Transcript of Ch 19 Climate Change and Ozone Depletion
and Ozone Depletion
Core Case Study: Studying a Volcano to Understand Climate Change
1. In 1991, Mount
erupted, which allowed
scientists to further study global
2. Scientists studied that amount of
released by the
volcano to determine if pollutants would indeed change the
climate of the Earth on a larger scale. It does.
19-1: How Might the Earth's Temperature
& Climate Change in the Future?
For the past 900,000 years the Earth has experienced period of global
. For the past 1,000 years the temperature has been
, but has begun to
in the last century when people began
clearing forests and burning fossil fuels.
How are past temperatures determined?
rocks and fossils
Bubbles of ancient
in ice cores
Temperature taken at different depths of the Earth
Life on Earth wouldn’t be possible without the natural
the Earth’s lower atmosphere
and surface due to greenhouse gasses like
CO2, water vapor, and CH4
that trap heat
from the sun
So what's the problem?
The problem is when we have
greenhouse gases and
activities have led to this increase.
-Mainly due to agriculture,
At our current rate of emission of CO2 we will have a concentration of
ppm by 2050, and according to research the
Top 2 CO2 emitting countries:
cores also shows that 60% of
emissions is due to
activity from extracting fossil fuels,
Nitrous Oxide levels have also increased due to use of Nitrogen
1.Between 1906-2000, average global surface temp has increased by
2. Greenhouse gas emissions has risen
and floating sea ice are melting
temps have risen twice as fast in the past 50 years
5. Rainfall patterns are changing
6. Sea level has risen by 4-8 inches
What Role Does the Ocean Play?
- Oceans absorb
of all of the
released and help moderate temperature
- Some Carbon is
converted to carbonate
salts that are buried in the sediments for millions of years
of CO2 decreases with
-As water heats, the CO2 isn't absorbed as easily and can amplify global warming=
-Higher levels of CO2 increases the
of the ocean, which decreases the ability of
to make calcium carbonate shells
**Bottom Line: Temperature, acidity, and ability to absorb CO2 from atmosphere are changing as a result of human activities
19-2: What are Some Possible Effects of a Warmer Atmosphere?
19-3: What Can We Do to Slow Climate Change?
Why is this complex problem is difficult so tackle:?
1. The problem is
- much international cooperation
2. Effects of climate change will last a long time- CO2 stays in atmosphere
3. It is a long term
4. Impacts of climate change are not spread
across the globe.
5.Phasing out fossil fuels would disrupt
Solutions: Three Major Prevention Strategies-
1. Improve energy
to reduce fossil fuel use.
2. Shift from nonrenewable
based fossil fuels to a mix of Carbon
renewable energy resources.
3. Stop cutting down tropical
** Effectiveness of these strategies would be enhanced by reducing
Output Strategies for Reducing Climate Change:
planting on degraded land in the tropics.
2. Plant fast growing perennial plants like
switchgrass- stores CO2 in
3. Carbon Capture & Storage (CCS)- removing
and pumping it
or abandoned oil or
-CCS is expensive and could raise prices
-require large inputs of
-earthquakes, war, etc could cause a
; even a small leak would be disastrous
1. Inject sulfate particles into
to cool troposphere
2. “Re-ice” the
3. Deep sea
to bring up nutrients for algal blooms which can take in
What Can the Government Do to Slow Climate Change?
1. Strictly regulate
2. Carbon taxes
Cap and Trade
to businesses who use green technologies
5.Technology transfer to
Protocol- a treaty to slow climate change (2005)
-requires countries to cut emissions of
Co2, CH4, and N2O
by 5.2% of their 1990 levels by 2012.
greenhouse gas emissions- the “cap and trade” system
-174 countries agreed to this. The US
*George W. Bush decided not to comply because he felt it would harm the
and he did not like how rapidly developing countries (like
aims to be the first carbon
country. They currently generate 78% of their electricity from renewable
power and 18% from
Some US States are tired of waiting on the federal government to take charge.
Who's Been Successful?
Portland, Oregon- 1st city to cut greenhouse gas emissions back to
*The city promotes energy efficient
and use of electricity from
*Has built many bicycle trails & has greatly expanded
*This has actually produced an economic
and has saved the city
/year in energy costs!
California- 12th largest producer of greenhouse gases (GHG) in the WORLD!
*2006- CA passed a law to cut GHG to
below 1990 levels by 2020.
*Set fuel efficiency and carbon emissions standards and let the free market find the best ways to meet standards- EPA refused this request. CA and 17 other states are now suing the federal government to allow states to set tougher CO2 emission standards.
Companies and Schools are reducing their Carbon Footprints
DuPont, IBM, Toyota, & Walmart have cut GHG emissions
Harmful Effects of Climate Change:
Global climate models say we must make a
cut in GHG emissions by 2050 so prevent Earth from heating up more than 3.6°F, which will likely be difficult to do. Therefore, analysts have compiled a list of things we need to do to prepare for the long-term effects of climate change. See Picture.
19-4: How Have We Depleted Ozone in the Stratosphere and What Can Be Done About It?
Not only is there considerable thinning of the ozone in the polar regions, but there is overall thinning everywhere as well, except over the tropics.
Ozone depletion in the
poses a serious threat to
, animals, and
and use expanded rapidly
*Trade name =
*Thought to be the dream chemical because it is chemically unreactive,
*Became popular as
in ACs, refrigerators, cleaners for electric parts, propellant in spray cans, aerosols, etc.
*Too good to be true: 1974- “CFCs destroy
in stratosphere” said Rowland and Molina
-CFCs rise and remain in atmosphere
-Once CFCs reach atmosphere, it breaks
down under the influence of the
which releases a highly reactive
which break O3 into O2 and O
-CFCs persist in atmosphere for
-It took Rowland and Molina 14 years to
convince DuPont to stop production
Why Should We Worry about Ozone Depletion?
1. More damaging
radiation reaches the Earth’s surface.
2. Sunburns, skin
- they play
a key role in removing
the base of ocean food web
How Can We Reverse Stratospheric Ozone Depletion?
1. Stop use of all ozone depleting chemicals
2. Montreal Protocol- treaty’s goal is to cut
emissions by 35%
(The US agrees with this one!)
Can One Degree Actually Make a Difference???