Monday, August 11, 2014

Latest Global Temperature: A Graph and Its Interpretation

Article: Global Warming Pause Puts 'Crisis' In Perspective
ArticleLatest Global temperature

Graph: Satellite-based temperature of the global lower atmosphere

The science and the graph.
The blue line represents the average monthly temperature, of the lower atmosphere, for the entire globe.
Since 1979, NOAA satellites have been carrying instruments which measure the natural microwave thermal emissions from oxygen in the atmosphere. The intensity of the signals these microwave radiometers measure at different microwave frequencies is directly proportional to the temperature of different, deep layers of the atmosphere.
The wavelength of electromagnetic energy is proportional to the temperature of an object. Planck's law is the mathematical expression of that relationship. Therefor, if one measures the electromagnetic radiation coming off an object (the earth, its atmosphere, the surface of a star or the sun) one can determine the temperature of that object.

Choose a starting point.
If we choose a starting point of mid-1998, the planet has cooled during the past 16 years. If we choose a starting point of late 1997 or early 1999, temperatures have been flat during the past 15 and 17 years. Examining the totality of the 35-year temperature record, we see approximately 1/3 of 1 degree Celsius warming during the period. Accordingly, global warming has occurred at a pace of approximately 1 degree Celsius per century over the duration of the satellite record.
The choice of starting and stopping points when looking at data can be manipulative.

Using the monthly averages, choose the Mt. Pinatubo cooling minimum and the El Nino warming maximum, and there is an increase of 1.2 degrees C (about 1.8 degrees F) in 5 years or 24 degrees C/century.

The El Nino warming maximum occurs just prior to the outbreak of global warming hysteria coinciding with the release of Al Gore's, "An Inconvenient Truth."

Choose the first and last monthly averages, and there is an increase of about 0.6 degrees C in 35 years. Or about 0.017 degree C/year or 1.7 degree C/century.

Choose the beginning of the running average, and there is an increase of one third degree C in 34 years. Or about 1 degree/century.

If one just looks at the graph, the temperatures pre-1998 (El Nino warming peak) are distinctly lower than the temperatures post-1998.

On the other hand, the bulk of the rise runs from about 1996 to 2002, if one ignores the El Nino maximum.

Because of a cooling trend ended in the 1970's, the 1970's are a frequent choice of starting time for discussions of global warming. When one is in the basement, everywhere is up.

The problem with the models. 
IPCC computer models dating from 1990 through the present have consistently predicted at least 2.4 degrees of global warming per century. Such warming would require at least 0.24 degrees Celsius per decade, for which we should see at least 0.80 degrees Celsius warming since 1979. However, real-world warming since 1979 is occurring at less than half that pace. And there has been absolutely no real-world warming during the past 17 years.
Computer models are simplifications of reality. Some factors are included in the model, others are left out. Everyone involved knows this and accepts it. However, if essential factors are left out, the models will be over-simplified, and will not work.

The models have never accurately reflected reality. They have always over-stated the amount of global warming that should happen. And that does not include the "hiatus" of the last 17 years.

Pulling this all together, we can reach the following conclusions:
  • The global warming pause is real.
  • The global warming pause is significant.
  • The global warming pause is not likely to be permanent.
  • A future resumption of global warming at pre-pause rates – or even modestly accelerated rates – would not validate IPCC global warming predictions, and would instead continue to undermine the IPCC’s predictions of very rapid 21st century global warming.
  • The most meaningful aspect of the global warming pause isn’t that temperatures have flattened for 17 years, but rather that the global warming pause extends and solidifies the longer-term record of smaller-than-predicted global temperature rise.
The 3rd point: I would argue that we do not know enough to be able to predict that global warming will resume.  We do not know why it paused in the first place. We do know if we are at the end of a warming trend that has been going on for the last 150 years. Or in the middle or what.

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