A Review of Temperature Reconstructions

By Andy May

In previous posts (here and here), I’ve compared historical events to the Alley and Kobashi
GISP2 Central Greenland Temperature reconstructions for the past 4,000 years. Unfortunately, these two reconstructions are very different. Recently Steve McIntyre has suggested a third reconstruction by Bo Vinther. Vinther’s data can be found here. Unfortunately, Vinther is often significantly different from the other two. The Alley data has been smoothed, but the details of the smoothing algorithm are unknown. So the other datasets have been smoothed so they visually have the same resolution as the Alley dataset. Both datasets (Kobashi and Vinther) were first smoothed with a 100 year moving average filter. Then 20 year averages of the smoothed data were taken from the one year Kobashi dataset to match the Vinther 20 year samples. The Alley data is irregularly sampled, but I manually averaged 20 year averages where the data existed. If a gap greater than 20 years was found that sample was skipped (given a null value).

All three reconstructions are shown in Figure 1. There is no reason to prefer one of the three reconstructions over the other two, so I simply averaged them. The average is the blue line. I’m not presenting this average as a new or better reconstruction, it is merely a vehicle for comparing the three reconstructions to one another and to other temperature reconstructions. This is an attempt to display the variability in common temperature reconstructions for the past 2,000 to 4,000 years.

Figure 1

Continue Reading

 

#average-global-temperature, #global-circulation-models, #hide-the-decline, #ipcc, #mikes-nature-trick

On the new EPA Carbon Dioxide emission rule for power plants on Regulations.gov

This is a comment I put on regulations.gov about the proposed new rule.

The key assumption in this rule is that man-made Carbon Dioxide is harmful to the environment by altering our climate. I do not think this is proven. The key elements of the debate on man-made catastrophic climate change are actually pretty simple. Obviously, climate changes and it is warmer than it was 150 years ago, so these facts are not in dispute. It is the “man-made” and the supposed impending catastrophe that are controversial.

Now, if we were to double the amount of CO2 in the atmosphere from the current 400 PPM (0.04%) to 800 PPM physics and chemistry would predict that the atmospheric temperature would increase a trivial 0.75 degrees C. The climate alarmists have used global circulation models (GCM’s) with a climate sensitivity factor that increases this to three or four degrees C by assuming positive feedbacks. These models generally assume that as CO2 goes up, water vapor will increase and since water vapor is a much stronger greenhouse gas than CO2 they speculate that temperature will spiral out of control with catastrophic effects. That is pretty much their case.

The problems with this are twofold. First there are no measurements to support the idea that water vapor will increase with CO2. In fact, the models suggest the highest rate of warming should be in the tropics because most water vapor is there and most heat enters the atmosphere there. But no significant warming has occurred in the tropics (or in Antarctica for that matter), warming has been almost entirely in the northern Northern Hemisphere and especially in the Arctic. Further, if more water is held in the atmosphere wouldn’t we get more clouds? Will the clouds make us warmer or cooler? No one knows, clouds are not in the GCM’s. Second, the GCM’s have not been successful in predicting anything yet. Observations have shown no increase in global temperature since 1998, but the models predicted an increase. The proportion of CO2 in the atmosphere has increased, why no increase in temperature?

We need to remember that man’s burning of fossil fuels contributes only 8% of the CO2 that goes into the atmosphere; respiration, microbial activity, volcanism, ocean outgassing, etc. provide the rest. We also need to remember that the average CO2 in the atmosphere after the dinosaurs and until the ice age (which we are still in) is 800 ppm. Atmospheric CO2 only decreased to 300 PPM (and perhaps less) due to the ice age. The article noted below provides actual evidence (not a computer model) that the additional climate sensitivity due to doubling CO2 to 800 ppm will increase the average temperature 1.093 degrees C. A trivial amount and a fraction of what the IPCC circulation models predict. This makes much more sense and is in line with what has been seen in the Earth’s history. If this article stands the test of time, it kills the entire alarmist argument. Some have said that computing or measuring climate sensitivity to CO2 is a fool’s errand and perhaps this is so. But, either way the alarmist argument is destroyed. It is far from certain that climate change is a problem or even unusual.

http://wattsupwiththat.com/2014/07/23/new-paper-finds-transient-climate-sensitivity-to-doubled-co2-levels-is-only-about-1c/#more-113314

Other references (Princeton Professor William Happer and MIT Professor Richard Lindzen):
http://live.wsj.com/video/opinion-climate-change-crack-up/B951E1BE-01A3-4F92-B871-A4AB9B171419.html#!B951E1BE-01A3-4F92-B871-A4AB9B171419
http://online.wsj.com/news/articles/SB10001424052748703939404574567423917025400

Dr. Roy Spencer
http://www.drroyspencer.com/global-warming-natural-or-manmade/

McKitrick and Vogelsang, 2014
http://climateaudit.org/2014/07/24/new-paper-by-mckitrick-and-vogelsang-comparing-models-and-observations-in-the-tropical-troposphere/

#climate-change, #climate-sensitivity, #global-circulation-models