Mitigation – the act of decreasing or reducing something• Taking actions aimed at reducing the extent of global

warming by reducing the production of greenhouse gases or their emission into the atmosphere

• We can improve energy efficiency, rely more on carbon-free renewable energy resources, and find ways to keep much of the CO2 we produce out of the troposphere.

Adaptation – change along with the changing climate• We recognize that some warming is unavoidable and

devise strategies to reduce its harmful effects, or live with the outcome.

What Are Our Options?

Solutions: Global Warming, Methods for Slowing Atmospheric Warming

Case Study:Is Capturing and Storing CO2 the Answer?

Carbon sequestration - removing CO2 from the atmosphere and storing it

Ways to Prepare for the Possible Long-Term Harmful Effects of Climate Change

A program to slow and adapt to global warming now is very likely to cost less than waiting and having to deal with its harmful effects later.

Governments can tax greenhouse gas emissions and energy use, increase subsidies and tax breaks for saving energy, and decrease subsidies and tax breaks for fossil fuels.

Getting countries to agree on reducing their greenhouse emissions is difficult.

Governments Can Help Reduce the Threat of Climate Change

In 1997, delegates from 161 countries met in Kyoto, Japan to negotiate a treaty on global warming which went into effect January, 2005.

It requires 38 participating developed countries to cut their emissions of CO2, CH4, and N2O to 5.2% below their 1990 levels by 2012.• This represents a reduction of 2010 levels by 29%

The protocol implements a “cap-and-trade” program that involves setting a cap or limit on emissions.• If a country emits less than their allowed limit, they can

sell the remaining allowances to another country.• Many countries distribute their allowance to specific

companies or power plants. Developing countries were excluded.

The Kyoto Protocol:International Climate Negotiations

191 countries have signed and ratified the protocol. U.S. signed the protocol but has not ratified it.

• Developing countries such as China, India and Brazil were considered exempt

• Belief that it would hurt the U.S. economy

The U.S. did not sign, but 10 U.S. states and 740 U.S. Cities are participating.

The Kyoto Protocol will have little effect on global warming without support and action by the U.S., China, and India.

The Kyoto Protocol:International Climate Negotiations

What is your carbon footprint?• The impact you have of the Earth (in terms of CO2

emissions) through your actions, decisions, and purchases.

Carbon neutral – a balance between the amount of carbon released into the atmosphere and the amount sequestered or removed from the atmosphere

Some Are Reducing Their Carbon Footprints

U.S. cities, states, businesses, and schools are taking initiatives to reduce carbon emissions

19-4 How Have We Depleted O3 in the Stratosphere and What Can We Do?

Concept 19-4A Widespread use of certain chemicals has reduced ozone levels in the stratosphere, which allows for more harmful ultraviolet radiation to reach the earth’s surface.

Concept 19-4B To reverse ozone depletion, we must stop producing ozone-depleting chemicals and adhere to the international treaties that ban such chemicals.

The ozone layer that is concentrated in the stratosphere keeps about 95% of the sun’s harmful UV radiation from reaching the earth’s surface.• UV rays damage skin • Sunburns, cancer

Less ozone in the stratosphere allows for more harmful UV radiation to reach the earth’s surface.

Our Use of Certain Chemicals Threatens the Ozone Layer

In the early 1980’s scientists noticed a seasonal depletion in the stratospheric ozone.

This ozone thinning was occurring in most of the atmosphere but was most severe over Antarctica and the Arctic.

The largest ozone depletions have occurred over Antarctica. The hole is the so-called ‘ozone hole’.

Our Use of Certain Chemicals Threatens the Ozone Layer

It is the greatest over Antarctica in spring because of the presence of polar clouds and weak Antarctic sunlight, which provide efficient mechanisms for ozone depletion.

During Oct./Nov. each year 40-50% of the ozone in the stratosphere over Antarctica and a smaller amount over the Arctic is depleted.

Our Use of Certain Chemicals Threatens the Ozone Layer

Chlorofluorocarbons (CFCs) were deemed responsible for the depletion of stratospheric ozone.• CFCs were used coolants in air conditioners and

refrigerators, propellants in aerosol cans, etc.

• There are other, similar ozone-depleting chemicals

CFCs are harmful because:• They are chemically stable• In the troposphere they acts as greenhouse gases and

eventually find their way into the stratosphere• In the stratosphere they break down ozone molecules• Each CFC molecule can last 65-385 years

Our Use of Certain Chemicals Threatens the Ozone Layer

SunOnce free, the chlorine atom is off to attack another ozone moleculeand begin the cycle again.

A free oxygen atom pulls the oxygen atom off the chlorine monoxide molecule to form O2.

The chlorine atom and the oxygen atom join to form a chlorine monoxide molecule (ClO).

UV radiation

Cl Cl

ClC

F

The chlorine atom attacks an ozone (O3) molecule, pulling an oxygen atom off it and leaving an oxygen molecule (O2).

Cl

Cl

OO

O

Cl

ClO

ClO

OO

OO

Ultraviolet light hits a chlorofluorocarbon (CFC) molecule, such as CFCl3, breaking off a chlorine atom and leaving CFCl2.

O

Summary of CFCs and Other Chlorine –Containing Compounds that Destroy Ozone

Natural Capital Degradation:Effects of Ozone Depletion

Montreal Protocol – A 1987 international treaty that controls the production and consumption of chemical that destroy the ozone layer.• Later strengthened and accelerated in 1992 by the

Copenhagen Protocol.

191 countries have ratified this treaty and many of them do not produce or consume any CFCs.

Substitutes for CFCs are available.

Some developing countries still use CFCs and other damaging chemicals.

We Can Reverse Stratospheric Ozone Depletion

Pollution Control DevicesEmission Control Devices – filter particles

Scrubbers – use water to filter particles and gases

Catalytic Converters – on cars; finish burning wastes to decrease carbon monoxide levels

1-800-453-SMOG

Human Impact (Positive)

Law – Clean Air Act

1963 - first passage 1970, 1977 and 1990 - amendedInvolves EPASets standards for acceptable levels of sulfur oxides, nitrogen oxides, ozone, carbon monoxide, hydrocarbons, lead, & moreProvides pollution credits for industries that utilize pollution-control devices+Bush administration has relaxed rulesIt established NAAQS and AQI

National Ambient Air Quality Standards (NAAQS)

Sets acceptable concentrations for 6 “criteria” pollutants that:

Threaten public health/the environment over broad areas (non-point)

Are emitted in large quantities

CO, Pb, Nitrogen Oxides, Ozone, Particulate Matter and Sulfur Dioxides

Air Quality Index (AQI)

Measures levels of 5 criteria pollutants

Forecast of daily air pollution levels

Purpose to educate and protect public- focuses on health effects

Categories: green= good, yellow= moderate, orange= unhealthy for sensitive groups, red= unhealthy, purple= very unhealthy

National Emissions Standards for Hazardous Air Pollutants

Regulates emissions (from point sources)For specific substances (air toxics w/ known or suspected serious health effects (mutagens, carcinogens, neurotoxins)Tend to be localized, from point sourcesExamples: Ammonia, chlorine, asbestos, arsenic, mercury, benzene

Extras - Funny

Extras - Funny Videos

A special message from our president:http://www.youtube.com/watch?v=rKMpQ6NqB3Q&feature=player_embedded

Not satisfied with the overwhelming evidence

for climate change?

Here is a “Second Opinion” on climate change:http://www.colbertnation.com/the-colbert-report-videos/81744/february-05-2007/the-word---second-opinion