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Understanding Global Warming


To understand global warming, we must first understand the Greenhouse Effect. ... If the amount increases, the Earth warms up - this is called Global Warming. ... – PowerPoint PPT presentation

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Title: Understanding Global Warming

Understanding Global Warming
  • A Live Green, Live Smart Presentation

The Greenhouse Effect
  • To understand global warming, we must first
    understand the Greenhouse Effect.
  • The Earths naturally mild temperature and
    climate is a result of the Greenhouse Effect.
  • Gases in the atmosphere, like carbon dioxide
    (CO2), methane (CH4), and ozone (O3), cover the
    Earth like the glass walls of a greenhouse.
  • These gases serve two purposes they protect the
    planet from receiving too much sunlight (and
    heat), and they trap sunlight to prevent it from
    escaping into space.
  • Normally these two actions are balanced perfectly
    so the Earths climate is warm and livable.

The Greenhouse Effect
  • A rapid change in greenhouse gas concentration
    causes the system to become unbalanced.
  • If the amount of greenhouse gas decreases, the
    Earth cools down, and can enter an Ice Age.
  • If the amount increases, the Earth warms up -
    this is called Global Warming.
  • If the Greenhouse Effect becomes too unbalanced
    in either direction, the Earth may become
    uninhabitable for humans.

Humans and Global Warming
  • Most scientists now believe the Earth is entering
    a period of global warming.
  • Many also believe that human activities are
    causing the Earth to warm at an unnaturally rapid

How Are Humans Contributing to Global Warming?
  • The primary human-related cause of global warming
    is the burning of fossil fuels like oil, coal,
    and natural gas.
  • When fossil fuels are burned, they release carbon
    dioxide into the air, which collects in the
    atmosphere as a greenhouse gas.
  • We use fossil fuels every day to power our cars,
    to light and heat (or cool) our homes, to
    manufacture goods, and to grow food.
  • We have also put more methane, ozone, and other
    greenhouse gases into the atmosphere through
    industrial and agricultural production.

How Are Humans Contributing to Global Warming?
  • Carbon dioxide levels in the atmosphere have
    increased 30 since the start of the Industrial
  • Methane levels have increased 150.
  • The result of this increase in greenhouse gas is
    that less of the sun's heat is able to escape
    through the atmosphere into space.
  • This heat stays trapped in the Earths climate.
  • As more greenhouse gases enter into the
    atmosphere, more of the suns heat is trapped
    and the Earth gets warmer and warmer.
  • In the last century the planets average
    temperature rose 1.3?F.
  • This may not seem like much, but we are already
    experiencing the effects of this increase.
  • The difference in temperature between the last
    Ice Age and todays climate is only 5?F.

When the Greenhouse Effect is altered so
drastically and so suddenly, the entire planet is
put in danger.
Dangers of Global Warming
  • Among the dangers posed to the climate by
    increasing temperatures are
  • Disruption of the Carbon Cycle
  • Changes in weather patterns, including more
    frequent severe storms, such as hurricanes
  • Droughts and water shortages in some places
  • Increased rainfall in others
  • Rising ocean levels
  • Vast, complex and often subtle changes are
    difficult to comprehend.
  • If we look at these changes in more specific
    terms, the degree of devastation becomes plainer.
  • The following slides are but a few examples of
    the effects of global warming on the climate.

The Carbon Cycle
  • Normally the planet has ways to deal with excess
    carbon in the atmosphere.
  • Plants eat carbon dioxide and produce oxygen,
    which animals eat, producing carbon dioxide.
  • This is called the Carbon Cycle.
  • Trees and ocean algae do most of this eating.
  • The amount of carbon dioxide in the atmosphere
    today has overloaded the Carbon Cycle it cannot
    keep up.
  • Deforestation and pollution in the oceans have
    also helped to reduce the effectiveness of the
    Carbon Cycle.

Changes in Weather
  • Since 1980 weve had 22 of the warmest years on
  • Six of the warmest have been within the last
    eight years.
  • Storms and hurricanes in North America and the
    Atlantic Ocean have become more frequent and more
  • Fatal consecutive summer heat waves have beset
  • Snow cover in the Northern Hemisphere has
    decreased 10 since 1966.
  • The Arctic Summer melting season increased
    between 1979 and 1998 the shortest was 57 days
    in 1979 the longest, 81 days in 1998.

  • According to the National Center for Atmospheric
    Research, Earth's dry, arid lands expanded from
    less than 15 of the total in the 1970s, to 30
    in 2002.
  • In 2002, record temperatures brought about severe
    droughts, causing a worldwide harvest loss of 90
    million tons. In 2004 there was a loss of 34
    million tons due to drought caused by increased
  • A study from corn- and rice-producing countries
    noted a 17 drop in crop yields with just a 1.8?F
    temperature rise.

Water shortages
  • A study done by the United States Geological
    Survey showed that the number of glaciers in
    Glacier National Park decreased from 150 in 1850,
    to less than 50 today they predict that there
    will be none in 30 years.
  • As the glaciers melt, less clean water is
    available for human use, and sources for crop
    irrigation are lost.
  • Worldwide, more than 1.5 billion people currently
    depend upon glacial sources for water.
  • Much of the American West is habitable only
    through water from glacial sources.
  • 70 of the snow packs of the Western United
    States will be gone by the middle of the century.

Rising Ocean Levels
  • The ocean could rise as much as one meter in this
    century, due to melting in the polar ice caps.
  • This may not sound like much, but the
    repercussions are huge.
  • Millions of people in crowded costal areas like
    Bangladesh, Shanghai, even Florida and Manhattan
    will be forced to relocate as these areas become
  • 40-50 of costal wetlands could be wiped out,
    killing off plant and animal species and leaving
    inland areas more susceptible to storms like
    hurricanes and tsunamis.

Life on a Warm Planet
  • Global warming will have a serious effect on the
    worlds plant and animal life.
  • Species biodiversity will suffer as hundreds of
    thousands, if not millions, of species become
    endangered or go extinct.
  • Humans will be especially affected by global

  • Because global warming is altering the climate so
    rapidly, many species of plants and animals will
    have no time to adapt.
  • These species risk endangerment and extinction.
  • Many of these species already face hardship
    thanks to deforestation and other human
  • The first extinction attributed entirely to
    global warming was the golden toad of Costa Rica.
  • Polar habitat animals, such as Arctic foxes,
    penguins, and polar bears, are literally seeing
    their homes melt away.
  • Rising temperatures in the ocean are killing off
    essential organisms like algae, plankton, and
  • Animals higher up in the food chain will see a
    loss of food supply and soon face the extinction
    risk as well.
  • Meanwhile, other species will thrive in the new
    climate and migrate around the world, throwing
    the planets biodiversity off balance.

The Human Toll
  • The species accelerating global warming stands to
    lose much due to climate change.
  • Entire regions could become completely
    uninhabitable to us for reasons including
  • Rising sea levels
  • Desertification
  • Intense heat
  • Loss of usable water
  • Loss of usable soil

The Human Toll
  • Clean freshwater will become a precious and
    increasingly rare commodity as our glaciers,
    lakes, rivers, and groundwater sources dry up.
  • Crop and livestock species will become less
    diverse and more susceptible to disease and
    climate change.
  • Diseases like malaria, already one of the worlds
    worst killers, will multiply around the world as
    temperate regions get warmer.

Are we past the point of no return?
  • Most experts believe there is still time to avoid
    drastic climate change.
  • However, there is no magic bullet to solve the
    coming crisis and reverse the damage we have done
    to the environment.
  • Instead, a series of changes must be implemented
    now. These necessary changes range from
    large-scale to small-scale.
  • The focus of these changes is to dramatically
    reduce our greenhouse gas emissions.

  • To stabilize the climate at at its present level,
    we must cut greenhouse gas emissions by 70.
  • To actually reduce atmospheric greenhouse gases,
    we must cut emissions still further.
  • Solutions fall into two general categories
  • Reducing energy use
  • Investing in alternative energy

Large-Scale Solutions
  • The Kyoto Protocol is the first international
    agreement to cut emissions of carbon dioxide and
    five other greenhouse gases.
  • The signatories agree to cut their emissions to
    1990 levels.
  • The United States and Australia are the only
    countries yet to sign Kyoto.
  • The European Union plans to reduce emissions 20
    by 2020. They hope to do this through a number of
  • Add 15,000 megawatts of wind power (enough to
    supply half the population of Europe)
  • Increase ethanol production five-fold
  • Increase biodiesel production three-fold
  • Germany plans to cut its emissions 67 by 2050 by
    cutting energy use and using renewable energy.
  • Iceland already heats 93 of its homes with
    renewable geothermal energy.
  • Many nations are investigating cap and trade
    programs that limit greenhouse gas emissions.

Small-Scale Solutions
  • Fixing the climate is not just an international
    matter. Is is within reach of the average person.
  • There are many things you can do to reduce your
    greenhouse gas emissions
  • Drive less or get a fuel-efficient car
  • Eat local foods as much as possible
  • Use an efficient heating and cooling system in
    your home
  • Use fluorescent light bulbs
  • Buy renewable power from your electric utility or
    install renewable energy sources in your house
  • This is far from a complete list of options.
    Learn more ways to reduce your greenhouse gas
    emissions at www.livegreenlivesmart.org

America ranksnumber one as a producer of
greenhouse gases.
  • Americans must participate in efforts to halt and
    reverse global warming.
  • If a basic understanding of the causes and
    dangers of rapid climate change is paired with
    the knowledge of better choices, we can
    immediately begin the work of saving the planet
    for future generations.

Thank you for your time and attention.
  • This has been a
  • Live Green, Live Smart presentation.

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