© National Wildlife Federation, 2007

Slides adapted and edited from:

What is global warming?

How Global Warming Works

Pollutant gases trap heat from leaving

The Sun’s energy passes through the car’s windshield.

This energy (heat) is trapped inside the car and cannot pass back through the windshield, causing the inside of the car to warm up.

Example of the Greenhouse Effect

Why is global warming happening?

Greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, ozone, and chlorofluorocarbons (CFCs)

Some of these come from

natural sources, but many come

from human (anthropogenic)

activities

The main sources of greenhouse gases are:

Water vapor: • Can be produced from the

evaporation of liquid water or from the sublimation of ice.

• Under typical atmospheric conditions, water vapor is continuously generated by evaporation and removed by condensation.

• Water vapor is lighter than air and triggers convection currents that can lead to clouds.

The main sources of greenhouse gases are:

• Carbon dioxide:

• Naturally found in our atmosphere, it is given off by organisms during cellular respiration. – Burning of fossil fuels and deforestation

leads to higher CO2 concentrations.

– Land use change (mainly deforestation in the tropics) account for up to one third of total anthropogenic CO2 emissions.

Burning of Fossil Fuels

Pollution from coal, natural gas, and oilPollution from coal, natural gas, and oilPollution from coal, natural gas, and oil

The main sources of greenhouse gases are:

Methane: • naturally produced by Livestock (as digestive gas)

and manure.• Wet muddy areas are ideal for methanogenic

bacteria, so rice paddy farming, land use and wetland changes contribute to CH4 levels.

• Sewage gases and vented landfill emissions leading to higher atmospheric concentrations of CH4.

The main sources of greenhouse gases are:

Chlorofluorocarbons (CFCs)

• Used in refrigeration systems (freon gas)

• Used in fire suppression systems and extinguishers (halon gas).

• Aerosol accelerants (gas in spray cans)

The main sources of greenhouse gases are:

Nitrous oxide • Agricultural activities, including the use of

fertilizers, that lead to higher N2O concentrations.

What’s the difference between “global warming” and

“climate change”?

DifferenceGLOBAL WARMING

is the increase of the Earth’s average surface temperature due to a build-up of greenhouse gases in the atmosphere.

CLIMATE CHANGE is a broader term that

refers to long-term changes in climate, including average temperature and precipitation.

A Correlation? Changes in Weather Patterns

• Water temp changes combined with Warmer atmosphere throws off earth’s weather patterns!

• Expect more frequent and severe droughts, floods, and hurricanes

• Another example:– El Niño Southern Oscillation (ENSO), results from a series of

interactions between the atmosphere and the tropical ocean. – It has been hypothesized that global warming trends may

increase both the frequency and duration of ENSO events.– Since 1976, there have been seven El Niños. Based on the

most reliable records, which go back 120 years, we would have expected to see only five.

Severe weather events• There also seems

to be an increase in the frequency and severity of HURRICANE activity that correlates to climate change

• Katrina, 2005

• Elevated greenhouse gas levels, has had a discernible influence on many physical and biological systems.

• Projected to impact various issues such as freshwater resources, industry, food and health.

Effects of Global WarmingIncreased Temperature

Habitat Damage and

Species Affected

Changes in Water Supply

Rising Sea Level

DesertificationDesertification:

conversion of semiarid

land to desert

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Excessive Excessive precipitation precipitation occurs in some places…

…while in other places, too little precipitation is causing problems

Deforestation• Less precipitation

and warmer air temperature dries out the soil, making it difficult for vegetation to grow.

Borneo map:

Negative Impact on Biodiversity

Recent studies show that atmospheric CO2 is being absorbed

into the oceans, etc, making them more ACIDIC. This kills plankton, among other things. How might this affect the oceanic ecosystem?

What’s the proof that global warming is taking place?

Portage Glacier

1914 2004

• Alaska

Photos: NOAA Photo Collection and Gary Braasch – WorldViewOfGlobalWarming.org

Colorado River• Arizona

June 2002 Dec 2003

When did global warming start?

Global Atmospheric Concentration of CO2

Human population growth

How is global warming measured?

Ice Core DataIce Core Data

COCO22 Measurements Before 1958 - Antarctica Measurements Before 1958 - Antarctica

Ice Core Data Graph of CO2 (Green graph), temperature (Blue graph), and dust concentration (Red graph) measured from the Vostok, Antarctica ice core as reported by Petit et al., 1999.

Higher dust levels are believed to be caused by cold, dry periods.

CO2 Atmospheric Measurements

CO2 Measurements Since 1958 – Mauna Loa, Hawaii

Temperature (Northern Hemisphere) CO2 Concentrations

1000 Years of CO2 and Global Warming

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April 2009 in the news:

• Here’s an inconvenient truth: A bridge to the Wilkins ice shelf, an Antarctic peninsula the size of Jamaica, has shattered.

• Scientists think the shelf is now on the brink of breaking away, a development that could be a direct effect of global warming in this part of Antarctica.

• Temperatures in Antarctica have risen up to 5.4 degrees Fahrenheit in the past 50 years, and shattering ice there has a big effect on sea levels worldwide.

• Read it at BBC News

Projections

2007

Goal: Reductions in CO2 Per Year

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2007Reductions

in CO2

Per Year

Gig

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Produce electricity efficientlyUse electricity efficientlyVehicle efficiencySolar and Wind PowerBiofuelsCarbon capture and storage

Bill

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Our Goal

What’s being done now to reduce our emissions?

Solar Power Wind Power Fuel-Efficiency

What can you do to help What can you do to help solve the problem?solve the problem?

Simple Things To Do

Turn off your computer or the TV when you’re not using it.

Take shorter showers. Heating water uses energy.

Keep rooms cool by closing the blinds, shades, or curtains.

Turn off the lights when you leave a room.

Use compact fluorescent bulbs.

Be Bulb Smart—Use CFLs

IncandescentCompact

Fluorescent

75% less energy used, lasts 10 x longer

What’s the difference?

•1,430 lbs. CO2 pollution avoided

•$30 saved

Simple Things To Do

Dress lightly when it’s hot instead of turning up

the air conditioning. Or use a fan.

Dress warmly when it’s cold instead of turning up the heat.

Offer to help your parents keep the air filters on

your AC and furnace clean.

Walk short distances instead of asking for a ride in the car.

Plant a tree. Recycle.

© National Wildlife Federation, 2007