Global Warming

Global Warming: Is it Real?

What's the evidence for global warming?

What do the latest models show? Here we see the predicted temperature increases on the land surface when the data is analyzed in cumulative time slices.

Here is the equivalent data for the oceans

Later we will compare the models with some data.

Current concentration of CO2 is 360 ppm

Current concentration of CH4 is 1.8 ppm or 25x1.8 = 45 ppm CO2 equivalent. This is 12% of CO2 concentration and its growing 2.5 times as fast.

More About Methane:

Time to run the simulation (not ready for public linkage yet).

Methane Removal Mechanism (some estimates suggest the methane residence time is up to 10 years so there is no short term equilibrium control):

Atmospheric Chemistry:

CH4 + 2O2 CO2 + 2H20

  • OH + CH4 + 02 H2O + CH3O2
  • CH3O2 + NO +02 H2CO + HO2 + NO2
  • CH3O2 + HO2 CH3OOH + O2
  • H2CO + uv H2 + CO
  • CH3OOH +OH H2O + CH3O2a

    Is this apparent reduction in the rate of methane build up due to a threshold effect that is does methane build up until the atmospheric chemistry is temporarily accelerated? Was Pinatubo to blame?

    An expert's view

    Ice Core Data:

    Manifestations and Predictions of the Greenhouse Effect:

    An example of Myth Perpetuation: Deforestation of the Amazon Rain Forest greatly contributes to the Greenhouse effect:

  • Its the total amount of biomass on the planet that contributes to the Carbon Cycle . Because of agriculture, this biomass is actually increasing with time (which contributes to the methane problem).

  • Trees are temporary storage only; they fall down and rot and release Carbon eventually

  • Biggest problem is that the Amazon Rain Forest is a net producer of greenhouse gases rather than a net sink. That is, this environment produces a great deal of methane which is emitted by the forest and that is larger than the amount of CO2 which is absorbed. This point is a bit controversial still, however.

  • The Amazon Rain Forest should be preserved as a species habitat; arguments to preserve it to "reverse" the Greenhouse effect are incorrect and demonstrate that people don't know about methane production and its effects.

    Simplest Prediction is increase in global mean temperature. Can We see evidence for this in the Data?

    Role of clouds is crucial --> Net Cooling or Warming? --> There is general consensus that cloud cover will increase as the capacity for the atmosphere to retain water increases with increasing temperature.

    What does the actual data look like?

  • All the Data: Global Warming NCDC Document

    Long Term Temperature Trends:

    Potential Problems:

    Distribution of Temperature trends on the Earth. Where is it getting warmest the fastest:

  • All the historical data

  • 1953-1973:

  • 1973-1993:

    When positional data is combined with temperature data and timesliced in this way - it seems clear the Global Warming is occurring. This conclusion was reached by a National Academcy of Science panel in Sept. 1995 and is accepted by most.

  • Temperature Variations with Altitude

    What about the US:

  • Annual US Trends
  • Max Temperature US Trends
  • Min Tempearture US Trends
  • Annual Precipitation Trends
  • Number of Tornadoes

  • Some Conclusions

  • Evidence of increased hurricane strength is here: Hurricane Andrew ; Elmira in the Pacific

    Some Additional Internet Resources:

  • Public Perception on Global Warming
  • Nice Overview
  • Technical Data on Gas Concentrations and Growth with time

  • Add your questions or comments about this particular lecture

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