The Role of Humans in Climate Change

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					The Role of Humans in
   Climate Change
    Oil International
Climate, Costs and Changes

             Natural Variability
        Inaccuracy in Proxy Data
     Prediction and Assumption Error
             Costs to humans
     Change over time, it’s natural
  Abrupt climate events have occurred in the Earth’s climate
                      pre-human activity.

•Dansgaard-Oeschger events- rapid warming episodes followed by gradual
cooling events. Closely related to Heinrich events in which the
thermohaline circulation is shut down.
•The little ice age cooling from mid 14th to mid 19th centuries (1300s to
1800’s). Ended the medieval climate optimum (warming). The Little Ice
Age is the peroid from which we are exiting presently.
                 Known Changes

   The younger dryas
    (12,000 ybp)-
    Shutdown of the
    circulation within 50
    year period greatly
    reducing average
    Lasted for about
    1,000 years and
    reversed in about 20
          Paleoclimate Proxies
   There are uncertainties in gathering data.
      Predictions and Assumptions
   “IAMs [Integrated Assessment Models] are based on a
    multitude of assumptions about the atmosphere and
    oceans, land cover and land use, economic growth, fossil
    fuel emissions, population growth, technological change,
    etc. However, making assumptions about what will happen
    in the future is a very difficult task. To begin with there is a
    natural human bias that the future will resemble the past. It
    is also very difficult to project events such as the energy
    crisis of the 1970s or the evolution of computer technology
    in the 1980s. The task for model developers is daunting--
    they not only must project how climate will change in the
    future, but they also must anticipate how society will
    evolve regardless of whether the climate changes”
    (CIESIN “Integrated Assessment Modeling”).
    Example of Uncertainty in Earth’s
           response system
   The Iris hypothesis proposed by Richard Lindzen states
    that the atmospheric water content possesses a “checks
    and balances” type system. “Much like the iris in a
    human eye contracts to allow less light to pass through
    the pupil in a brightly lit environment, Lindzen suggests
    that the area covered by high cirrus clouds contracts to
    allow more heat to escape into outer space from a very
    warm environment” (NASA Earth Observatory).
   The debate of this theory lies in the percentage as well
    as the albedo and outgoing longwave/ net flux of the
    clouds. These assumptions create differing results for
    different groups.
Are Humans or Oil Responsible??
      How can we know??

   The future of the Earth’s climate is very
    uncertain. The ability to predict climate
    in future periods is based on
    assumptions and data sets riddled with
      And what is the cost??
 Oil Companies are being targeted as the
  scapegoat of Carbon Dioxide emissions
  without substantially solid information.
 Reductions in oil and increased taxes on
  oil, etc. will impact every area of a
  countries economy. Shipping, farming, air
 A challenge to think about your morning
   Chris Scotese, University of Texas, Arlington
   Columbia University Center for International Earth
    Science Information Network
   NASA Earth Observatory
   Scientific American Frontiers
   Lomborg, Bjorn. “The Skeptical Environmentalist”
   World Climate Report