Global Climate Change

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Global Climate Change

• The worry over global climate change has existed
  in the past few decades, although it became more
  intense since the early 1980s.
• An overwhelming majority of the worlds
  scientists that are doing research in this area
  agree that climate change is happening as we
  speak.
• Lets start with a brief discussion on how the
  process actually works.

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• The process begins with a phenomenon called the
  greenhouse effect.
• Light from the sun hits the earth constantly and
  gets absorbed by the earths surface.
• Some of this gets released back into the
  atmosphere as heat.
• The presence of certain gases in the atmosphere
  traps this heat, eventually raising the
  temperature of the earths surface.

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• So what are the major greenhouse gases?
• Water vaporthe most significant greenhouse gas,
  results of natural water cycle
• Carbon dioxidesignificant impact, part of the
  natural carbon cycle, but large quantities are
  also released through fossil fuel usage,
  deforestation, and industrial pollution
• Methanereleased through decomposition of organic
  substances, but also through agriculture,
  production of fossil fuels
• Apart from these there are other greenhouse gases
  such as nitrous oxide, halocarbons etc.

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• But isnt it true that the climate has always
  been changing?
• A very common argument often used to argue
  against climate change.
• While it is certainly true that the earth has
  experienced changes in climate in the past, the
  trend in recent decades has been very different.
• A number of studies have shown that human
  influence has greatly accelerated the recent
  change in climate.

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• So.how much climate change has there been?
• Lets examine that with a graph.

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The Hockey Stick Effect
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• Next to water vapor, carbon dioxide is the most
  significant greenhouse gas.
• How has the emission of carbon dioxide changed
  over the years?
• Lets take a look at a couple of graphs.

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Current and projected CO2 emissions
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• What are the impacts of global climate change?
• The most immediate impact is, of course the
  change in world temperature.
• The following map shows the projected change in
  temperature in the U.S. and Canada.

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• The rise in temperature is associated with a
  number of other impacts.
• Melting polar icecap is one of these impacts.
• The following map demonstrates this.

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• Changing temperature also brings other changes in
  the climate.
• Changes in precipitation patterns is an important
  one.
• This change will dramatically change the
  availability of water.

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• Melting polar ice is projected to cause a rise in
  the sea level.
• This makes many coastal communities around the
  world, including the U.S., vulnerable.

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• Species in natural ecosystems will attempt to
  migrate with the changing climate, but will
  differ in their degree of success.
• U.S. agriculture and forestry will likely
  experience mixed results with moderate warming,
  productivity may increase in northern states and
  possible declines in southern states. 
• However, at higher levels of warming, the risk of
  adverse effects across the nation increases.

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• The risk of disasters such as storms, devastating
  fires also increase.
• Human health may be affected in a variety of ways
  including extreme temperatures (i.e., heat
  waves), air pollution, severe weather, and
  increased spread of infectious diseases.

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• All of these impacts are likely to cause
  significant economic loss.
• The following chart shows changes in weather and
  flood-related economic loss over the last forty
  years.

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