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					Global Warming Debate
          Q&A: Climate change
• Accelerating ice-melt may be a sign
  of global climate change
• The Earth is getting warmer.
  Scientists predict increasing
  droughts, floods and extreme
  weather and say there is growing
  evidence that human activities are
  to blame.
• BBC News Online looks at the key
  questions behind climate change
  and global warming.
        http://news.bbc.co.uk/1/hi/sci/tech/3928017.stm
• What is climate change?
• The planet's climate is constantly changing. The
  global average temperature is currently in the
  region of 15C. Geological and other evidence
  suggests that, in the past, this average may
  have been as high as 27C and as low as 7C.
• But scientists are concerned that the natural
  fluctuation has been overtaken by a rapid
  human-induced warming that has serious
  implications for the stability of the climate on
  which much life on the planet depends.
• What is the "greenhouse effect"?
• The "greenhouse effect" refers to the role played by a
  layer of gases which effectively trap the heat from the
  Sun in the Earth's atmosphere. Without them, the planet
  would be too cold to sustain life as we know it.
• These gases include carbon dioxide, methane and
  nitrous oxide, which are released by modern industry,
  agriculture and the burning of fossil fuels.
• Their concentration in the atmosphere is increasing - the
  concentration of carbon dioxide has risen by more than
  30% since 1800.
• The majority of scientists accept the theory that an
  increase in these gases will cause a rise in the Earth's
  temperature.
• What is the evidence of warming?
• Temperature records go back to the late 19th Century
  and show that global average temperature increased by
  about 0.6C in the 20th Century.
• Sea levels have risen 10 - 20cm - thought to be due
  mainly to the expansion of warming oceans.
• Most of the recorded non-polar glaciers are in retreat
  and records show Arctic sea-ice has thinned by 40% in
  recent decades in summer and autumn.
• There are anomalies however - parts of the Antarctic
  appear to be getting colder, and there are discrepancies
  between trends in surface temperatures and those in the
  troposphere.
• How much will temperatures rise?
• If nothing is done to reduce emissions, current climate
  models predict a global temperature increase of 1.4 -
  5.8°C by 2100.
• To put this in context, global temperatures are thought to
  have fluctuated by only one degree Celsius since the
  dawn of human civilisation.
• Even if we cut greenhouse gas emissions dramatically
  now, scientists say the effects would continue because
  parts of the climate system, particularly large bodies of
  water and ice, can take hundreds of years to respond to
  changes in temperature.
• Some scientists say it is possible that we have already
  irrevocably committed the Greenland ice sheet to
  melting.
• This would take centuries - if not millennia - but would
  cause an estimated seven metre rise in sea level.
• How will the weather change?
• Globally, we can expect more extreme weather events,
  with heat waves becoming hotter and more frequent.
• Scientists predict more rainfall overall, but say the risk of
  drought in inland areas during hot summers will
  increase.
• More flooding is expected from storms and rising sea
  levels.
• There are, however, likely to be very strong regional
  variations in these patterns, and these are difficult to
  predict.
• What will the effects be?
• The potential impact is huge, with predicted freshwater
  shortages, sweeping changes in food production
  conditions, and increases in deaths from floods, storms,
  heat waves and droughts.
• Poorer countries, which are least equipped to deal with
  rapid change, will suffer most.
• Plant and animal extinctions are predicted as habitats
  change faster than species can adapt, and the World
  Health Organisation has warned that the health of
  millions could be threatened by increases in malaria,
  water-borne disease and malnutrition.
• What don't we know?
• We don't know exactly how much warming is caused by
  human activities or what the knock-on effects of the
  warming will be.
• Global warming will cause some changes which will
  speed up further warming, such as the release of large
  quantities of the greenhouse gas methane as permafrost
  melts.
• Other factors may mitigate warming - such as plants
  taking more CO2 from the atmosphere as their growth
  rate is increased by warmer conditions.
• Scientists are sure how the complex balance between
  these positive and negative feedback effects will play
  out.
• What about the sceptics?
• Most global warming sceptics do not deny that the world
  is getting warmer, but they do doubt that human activity
  is the cause.
• Some say the changes now being witnessed are not
  extraordinary - similar, rapid changes can be seen at
  other times in Earth's history when humans did not exist.
• Some point to the Sun's present high activity as the
  prime influence on recent temperature trends.
• Nevertheless, there is a growing scientific consensus
  that, even on top of the natural variability of the climate,
  something out of the ordinary is happening and humans
  are to blame.
• What is the international community doing?
• An international agreement, the Kyoto Protocol, commits
  industrialised countries to specific targets for reducing
  their greenhouse gas emissions.
• It must be ratified by a certain number of countries
  before it becomes binding. The protocol suffered a huge
  blow when the US - responsible for a quarter of global
  emissions - pulled out in 2001.
• The agreement will now only come into force if Russia
  ratifies it.
• While many countries have taken steps to reduce their
  emissions, the Kyoto targets are just a fraction of the
  emissions reductions thought necessary to slow global
  warming significantly.
• History of Global Warming

 NOW with Bill Moyers
• Debating Global Warming

 NOW with Bill Moyers
Skeptical of global warming fears:     In favor of a global effort to
                                       reverse climate change:


"Environmentalists have viewed         "Even if the theory of global
climate change as a catastrophe        warming is wrong, we will be
necessitating immediate and major      doing the right thing — in terms
steps to head off or mitigate.         of economic policy and
Whether global warming will occur is   environmental policy."
uncertain. Although temperature        - Tim Wirth, former U.S.
data until now could reflect a         Senator from Colorado
warming planet, they are also
consistent with normal fluctuations
in weather. From a scientific
viewpoint the evidence for global
warming must be 'not proven.'"
- Thomas Gale Moore, Hoover
Institute



    Source: http://www.pbs.org/now/science/climatedebate.html
Skeptical of global warming fears:       In favor of a global effort to
                                         reverse climate change:


"I believe that it is fair to say that   "In the United States…we have to
the people once labeled as 'a small      first convince the American
band of skeptics' — those who            people and the Congress that the
championed the position that             climate problem is real."
warming would be modest and              - former President Bill Clinton,
primarily in the coldest air-masses      1997 address to the United
have won the day. Many of these          Nations
same scientists are now forming a
new environmental paradigm. It is
that the concept of 'fragile earth'
must be abandoned. And it asks the
impertinent question: since when is
everything that man does to the
planet necessarily bad?"
- Patrick J. Michaels, CATO
Institute Congressional
Testimony

     Source: http://www.pbs.org/now/science/climatedebate.html
Skeptical of global warming fears:    In favor of a global effort to
                                      reverse climate change:


"Scientists who want to attract       "People are changing the climate
attention to themselves, who want     that made life on earth possible
to attract great funding to           and the results are disastrous -
themselves, have to (find a) way to   extreme weather events, such as
scare the public…and this you can     droughts and floods, disruption of
achieve only by making things         water supplies, melting Polar
bigger and more dangerous than        regions, rising sea levels, loss of
they really are."                     coral reefs and much more.
- Petr Chylek, Professor of           It is not too late to slow global
Physics and Atmospheric               warming and avoid the climate
Science, Dalhousie University,        catastrophe that scientists
Halifax, Nova Scotia                  predict. The solutions already
                                      exist. Renewable energy sources
                                      such as wind and solar offer
                                      abundant clean energy that is
                                      safe for the environment and
                                      good for the economy."
                                      - Greenpeace

    Source: http://www.pbs.org/now/science/climatedebate.html
Skeptical of global warming fears:     In favor of a global effort to
                                       reverse climate change:


"The Little Ice Age and the Medieval   "Emissions of greenhouse gases
Warming that preceded it from 950      and aerosols due to human
to 1300 AD stand out in every          activities continue to alter the
temperature record as the major        atmosphere in ways that are
weather events of the last 1,000       expected to affect the climate."
years, and they're a hefty problem     - Summary for Policymakers,
for global warming advocates. If the   A Report of Working Group 1
world was warmer in 1200 AD than       of the Intergovernmental
today, and far colder in the year      Panel on Climate Change
1400, why would we blame current
temperatures trends on auto
exhausts?"
- Dennis Avery, Center for Global
Food Issues


   Source: http://www.pbs.org/now/science/climatedebate.html
• BBC Global warning? program
                          CLIMATE WARS

                    Programme 1: The science

 Two Harvard astronomers became the toast of Washington as they
 attacked the consensus view that global warming is a problem, and
argued that humanity has survived similar episodes as recently as the
                           Middle Ages.

Gerry Northam charts the genesis and fate of this research, how it has
been taken up by Washington conservatives, and the highly enflamed
                       debate that followed.
                         CLIMATE WARS

                    Programme 2: The action

The Kyoto protocol was meant to be the first step towards stopping
 and reversing global warming, but when the US declared it would
 have nothing to do with it in 2001, the treaty looked dead. That's
          what the US administration argued at the time.

But with Russia perhaps on the brink of signing the protocol, despite
   a fog of words suggesting the opposite, and with the rest of the
 industrialised world and even individual states in the USA moving
 ahead with climate measures, it may be that Washington gets left
                               behind.
• The Kyoto Agreement BBC site
                               Extreme Weather

• Increasing temperatures means the World is likely to see less frosty days
  and cold spells, but we are expected to experience an increase in heat
  waves and hot spells
• Greater risk of drought in summer in continental areas
• The greatest warming over the next 100 years is expected to be at higher
  latitudes and the smallest amount of warming, in the tropics
• Increase in extreme precipitation events
• Hurricanes likely to be more intense in some parts of the World due to
  more rainfall and more intense winds
• It’s not clear what will happen with thunderstorms or tornadoes
• An intensification of the Asian summer monsoon is expected
• There is no evidence for changes in the frequency, intensity or location of
  tropical storms
• Storm surges are expected to increase in frequency and in the UK the
  south east coast is expected to see the largest surges at around 1.2m
  higher than we have now (this is in the 2080’s with the "medium high
  emissions" scenario)

				
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posted:10/6/2011
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