Transcript What is global warming?

Slides adapted and edited from:
© National Wildlife Federation, 2007
What is global warming?
How Global Warming Works
Pollutant gases trap heat from leaving
Example of the
Greenhouse Effect
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.
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 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”?
Difference
GLOBAL 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 Warming
Rising Sea Level
Increased Temperature
Habitat Damage and
Species Affected
Changes in Water Supply
Excessive
precipitation occurs
in some places…
…while in other
places, too little
precipitation is
causing problems
Desertification:
conversion of semiarid
land to desert
19
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
• Alaska
1914
Photos: NOAA Photo Collection and Gary Braasch – WorldViewOfGlobalWarming.org
2004
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 Data
CO2 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
1000 Years of CO2 and
Global Warming
Temperature
(Northern Hemisphere)
Year
Year
2000
1800
1600
1400
1200
1000
2000
1800
1600
1400
1200
1000
Parts Per Million
Degree Celsius Increase
CO2 Concentrations
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
Billions of Metric Tons Carbon
Goal:
Reductions in
2007
CO2 Per Year
of Metric
Billions
Carbon Tons Carbon
Gigaton
Our Goal
2007
Reductions
in CO2
Per Year
Produce electricity
efficiently
Use electricity
efficiently
Vehicle efficiency
Solar and Wind
Power
Biofuels
Carbon capture
and storage
What’s being done now to
reduce our emissions?
Wind Power
Solar Power
Fuel-Efficiency
What can you do to help
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
Incandescent
What’s the
difference?
Compact
Fluorescent
•1,430 lbs. CO2 pollution avoided
•$30 saved
75% less energy used, lasts 10 x longer
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