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Federal Climate Committee Mislead Again

February 12, 2013
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By Paul Homewood

 

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Under its Global Climate Change Research Program, the US government has set up the National Climate Assessment and Development Advisory Committee or NCADAC, which has just released its Draft Climate Assessment Report. It will come as no surprise that this report contains  reams of alarmist statements and predictions.

We have already seen that its claims about worsening floods are not supported by the experts at the USGS.

Now let’s examine what it has to say about temperatures.

 

U.S. average temperature has increased by about 1.5°F since 1895; more than 80% of this increase has occurred since 1980.

This may sound rather startling, until you look at the full picture, which they seem remarkably reluctant to show.

 

 

NOAA, National Environmental Satellite, Data, and Information ServiceNational Climatic Data Center, U.S. Department of Commerce

Climate At A Glance

Annual Temperature
Contiguous United States


 

Annual 1895 – 2012 Data Values:

Annual 1901 – 2000 Average = 52.07 degF
Annual 1895 – 2012 Trend = 0.13 degF / Decade

 

image

http://www.ncdc.noaa.gov/oa/climate/research/cag3/na.html

 

As they rightly say, temperatures have increased by 1.5F since 1895, i.e. 0.13F/decade. But a comparison with 1980 hides the fact, that temperatures were also relatively high in the 1930’s and 40’s, before the onset of a much colder period. So what would a comparison with the 1930’s show?

 

NOAA, National Environmental Satellite, Data, and Information ServiceNational Climatic Data Center, U.S. Department of Commerce

 

Climate At A Glance

Annual Temperature
Contiguous United States


Annual 1901 – 2000 Average = 52.07 degF
Annual 1930 – 2012 Trend = 0.12 degF / Decade

 

image

 

Lo and behold, the long term trend is 0.12F/decade, comparable to the trend of 0.13F since 1895. Meanwhile, between 1930 and 1979, there was a huge decline of 0.23F/decade.

 

NOAA, National Environmental Satellite, Data, and Information ServiceNational Climatic Data Center, U.S. Department of Commerce

 

Climate At A Glance

Annual Temperature
Contiguous United States

Annual 1901 – 2000 Average = 52.07 degF
Annual 1930 – 1979 Trend = -0.23 degF / Decade

 

image

 

 

Atlantic Multidecadal Oscillation

Now, of course, I could be cherry picking just as much as they are, by comparing back to 1930. Except, for one very good reason – the Atlantic Multidecadal Oscillation, or AMO.

According to NOAA,

The AMO has affected air temperatures and rainfall over much of the Northern Hemisphere, in particular, North America and Europe. It is associated with changes in the frequency of North American droughts and is reflected in the frequency of severe Atlantic hurricanes. It alternately obscures and exaggerates the global increase in temperatures due to human-induced global warming.”

“However, studies of paleoclimate proxies, such as tree rings and ice cores, have shown that oscillations similar to those observed instrumentally have been occurring for at least the last millennium. This is clearly longer than modern man has been affecting climate, so the AMO is probably a natural climate oscillation

 

Their graph shows the effect clearly.

 

faq_fig2

The solid blue curve shows the observed northern Hemisphere temperatures and the dashed blue curve is a smoothed version. The red curve is the temperature history for a model that responds to the external forcing of greenhouse gases and solar variability but not to natural climate variations. The blue alternations about the red curve represent the natural AMO oscillations. When the AMO decreases, as from 1950 to 1975, global warming may appear to be reversed. When the AMO increases, as from 1975 to the present, the global warming (red) is exaggerated.

http://www.aoml.noaa.gov/phod/faq/faq_fig2.php

 

 

 

image

https://notalotofpeopleknowthat.wordpress.com/2013/01/07/facts-about-the-amo/

 

The graph above shows the AMO cycle. We entered the current warm phase in the mid 1990’s. The previous warm phase lasted from around 1930 – 1960.

Any analysis of US temperatures, or for that matter NH ones, which ignores the AMO cycle is inherently flawed. As AMO cycles last about 30 years, we are likely to remain in the warm phase for another decade. After that, we could be facing another period of falling temperatures.

There can be no doubt at all that the experts, who wrote this report, would have been aware of this fact. Which raises the question, why they deliberately chose to ignore it?

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8 Comments
  1. February 12, 2013 3:26 pm

    “Which raises the question, why they deliberately chose to ignore it?”

    Because it contradicts both the message and the desired reality?

  2. February 12, 2013 5:09 pm

    Reblogged this on goobersite.

  3. Robin permalink
    February 12, 2013 8:44 pm

    I would like to download a single file with all the monthly data for the whole period. The options on the site don’t seem to allow this. Any suggestions?

    Robin

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