Global Climate Models

By Andy May

Global Climate Models (GCM) are used to compute the social cost of carbon dioxide emissions and to compute man’s contribution to recent global warming. The assertion that most of “climate change” is due to man’s influence is based solely on these models. They are also the sole basis for concluding “climate change” is dangerous. Just how accurate are they? How close are their predictions to observations?

Dr. Judith Curry has written an important white paper, for the layman, describing how the models work. It is easy to understand and well worth reading.

Her key conclusions:

GCMs have not been subject to the rigorous verification and validation that is the norm for engineering and regulatory science.

There are numerous arguments supporting the conclusion that climate models are not fit for the purpose of identifying with high confidence the proportion of the 20th century warming that was human-caused as opposed to natural.

There is growing evidence that climate models predict too much warming from increased atmospheric carbon dioxide.

Some portions of the GCMs are rooted in fundamental physics and chemistry, but there are thousands of atmospheric and surface processes that cannot be deterministically modeled and must be “parameterized” using simple empirical formulas based on observations. These empirical formulas are “tuned” or “calibrated” to make the models match observations. They are tweaked to match the twentieth century, especially the warming period from 1945 to 2000. Even with all of the tuning, the models do a very poor job matching the warming from 1910-1945.

Since all models are “tuned” to the twentieth century (see Voosen, et al., Science, 2016) and since the “more than half of warming is due to man” conclusion is based upon comparing two model runs “from 1951 to 2010” the validity of the computation of man’s influence is highly questionable. Dr. Curry points out:

“GCMs are evaluated against the same observations used for model tuning.”

This is not something that inspires confidence. Further, the Earth has been warming for 300 to 400 years, as Dr. Curry writes:

“Understanding and explaining the climate variability over the past 400 years, prior to 1950, has received far too little attention. Without this understanding, we should place little confidence in the IPCC’s explanations of warming since 1950.”

She adds:

“Anthropogenic (human-caused) climate change is a theory in which the basic mechanism is well understood, but of which the potential magnitude is highly uncertain.”

Precisely so.

Global Warming and Extreme Weather

By Andy May

In this post, the sixth of seven, we will discuss the connection between climate change and extreme weather. In previous posts, we’ve discussed whether humans are harming the environment, whether our population is growing too fast, the cost of global warming, are species extinctions increasing, and climate related mortality.

In the IPCC WGII AR5 Technical Summary, page 52, they list the following risks of climate change, among others:

“Virtually certain that, in most places, there will be more hot and fewer cold temperature extremes as global mean temperatures increase, for events defined as extremes on both daily and seasonal time scales.”

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How constant is the “solar constant?”

The IPCC lowered their estimate of the impact of solar variability on the Earth’s climate from the already low value of 0.12 W/m2 (Watts per square-meter) given in their fourth report (AR4), to a still lower value of 0.05 W/m2 in the 2013 fifth report (AR5), the new value is illustrated in Figure 1. These are long term values, estimated for the 261-year period 1750-2011 and they apply to the “baseline” of the Schwabe ~11-year solar (or sunspot) cycle, which we will simply call the “solar cycle” in this post. The baseline of the solar cycle is the issue since the peaks are known to vary. The Sun’s output (total solar irradiance or “TSI”) is known to vary at all time scales (Kopp 2016), the question is by how much. The magnitude of short-term changes, less than 11 years, in solar output are known relatively accurately, to better than ±0.1 W/m2. But, the magnitude of solar variability over longer periods of time is poorly understood. Yet, small changes in solar output over long periods of time can affect the Earth’s climate in significant ways (Eddy 1976) and (Eddy 2009). Continue reading

The Great Climate Debate Report

By Andy May

After I posted my series on the great climate debate between Dr. William Happer and Dr. David Karoly, hosted by TheBestSchools.org, I received several requests to pull the series together into one pdf. This is now done, and the pdf can be downloaded here.

Since the series was posted, we have found out that Dr. William Happer has joined the White House as a top advisor. Dr. Happer is 79 years old and has confirmed that he began serving on the National Security Council, under National Security Advisor John Bolton on Tuesday, September 4. Congratulations Will! Read the details by Hannah Northey here.

Update:  I’ve created an epub format edition of the report.  It can be downloaded here. Due to restrictions on my website, I had to zip the file.  After downloading, unzip the file and then open the epub file with Internet Explorer, Nook, or some other ebook reader.

Does Global Warming increase total atmospheric water vapor (TPW)?

By Andy May

Some have speculated that the distribution of relative humidity would remain roughly constant as climate changes (Allen and Ingram 2002). Specific humidity can be thought of as “absolute” humidity or the total amount of water vapor in the atmosphere. We will call this amount “TPW” or total precipitable water with units of kg/m2. As temperatures rise, the Clausius-Clapeyron relationship states that the equilibrium vapor pressure above the oceans should increase and thus, if relative humidity stays the same, the total water vapor or specific humidity will increase. The precise relationship between specific humidity and temperature in the real world is unknown but is estimated to be between 0.6 to 18% (10-90%ile range) per degree Celsius from global climate model results (Allen and Ingram 2002).

Carl Mears and colleagues (Mears, et al. 2018) have recently published a satellite microwave brightness record of TPW from 1988 to 2017 showing TPW, over the world’s ice-free oceans, increasing in lockstep with global mean temperature. This surprised me since Benestad (Benestad 2016), (Partridge, Arking and Pook 2009), (Miskolczi 2014) and (Miskolczi 2010) have previously reported that TPW, as computed from weather balloon data, has gone down recently, although their time periods were earlier and longer than the record shown in Mears, et al. Continue reading

Stephen, Why Global Warming is not a problem

 

By Andy May

The following is a quote from my book Climate Catastrophe! Science or Science Fiction?

“99.9 percent of the Earth’s surface heat capacity is in the oceans and less than 0.1 percent is in the atmosphere. Further, CO2 is only 0.04 percent of the atmosphere. It beggars belief that a trace gas (CO2), in an atmosphere that itself contains only a trace amount of the total thermal energy on the surface of the Earth, can control the climate of the Earth. This is not the tail wagging the dog, this is a flea on the tail of the dog wagging the dog.”

One would think that this is clear, but to some it clearly is not. A commenter on Amazon.com named “Stephen” thinks it is “Scientific gibberish” and explains as follows:
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The Atmospheric Lapse Rate and Molar Density

By Andy May, Michael Connolly and Ronan Connolly

In this post, we will discuss the tropopause, atmospheric molar density and the lapse rate (the change in atmospheric temperature with altitude). The key points are:

  1. A change in the molar density versus pressure best-fit line is a change in the equation-of-state.
  2. The NOAA and WMO definitions of the tropopause are different and somewhat clumsy.
  3. Molar density plots are a better and more robust way to pick the tropopause.

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