“… the historical and geological record suggests recent changes in the climate over the past century are within the bounds of natural variability.”  (p. 10)

“Projections of future climate and weather events rely on models demonstrably unfit for the purpose. As a result, rising levels of CO2 do not obviously pose an immediate, let alone imminent, threat to the earth’s climate.” (p. 10)

The CO2 Coalition has posted the amicus curiae brief of Dr. William Happer, President of the CO2 Coalition; Dr. Richard Lindzen, a Coalition Director; and Dr. Steven Koonin concerning lawsuits filed by Oakland, San Francisco, et al. against certain large oil companies. The plaintiffs want to recover costs associated with climate adaptation.

This brief is in response to U.S. District Judge William Alsup’s request for a tutorial on climate change and climate science. Excerpts from the Happer/Lindzen/Koonin brief follow:

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Four Conclusions (p. 1):

1. The climate is always changing; changes like those of the past half-century are common in the geologic record, driven by powerful natural phenomena

2. Human influences on the climate are a small (1%) perturbation to natural energy flows

3. It is not possible to tell how much of the modest recent warming can be ascribed to human influences

4. There have been no detrimental changes observed in the most salient climate variables, and today’s projections of future changes are highly uncertain

Quotations:

“As human influences were significant only after about 1950, the [temperature] graph suggests that the climate is quite capable of varying significantly on its own.” (p. 4)

“Even within the instrumental record, the warming of the past four decades is not unusual. (p. 4)

“The largest anthropogenic cooling influences are associated with aerosols; they are quite uncertain.” (p. 4)

“Carbon dioxide, which is accumulating in the atmosphere largely due to fossil fuel use, exerts the strongest  warming influence, although small compared to the natural energy flows. Methane and other well-mixed greenhouse gases are also important.” (p. 5)

“The largest anthropogenic cooling influences are associated with aerosols; they are quite uncertain. Changes in the solar irradiance over the past 250 years are shown to be negligible.” (p. 6)

Climate Models

“One major challenge [for climate model parameterization] is that there are many important weather phenomena that occur on scales far smaller than the grid size (e.g., topography, clouds, storms) and so the modeler must make  assumptions about these “sub gridscale” processes to build a complete model. For example, given the temperature and humidity profiles of the atmosphere in a grid box, “How high, how many, and of what type are the clouds?”  While these subgrid-scale parametrizations can be based upon observations of weather phenomena, there is still 
considerable judgment in their formulation.” (p. 6)

“[Climate] models are not, as one often hears, ‘just physics’ since the parameters in each must be ‘tuned’ to reproduce aspects of the observed climate.” (p. 6)

“[T]here is no unique tuning that reproduces the historical climate data.” (p. 6)

“Since aerosol cooling plays against GHG warming, a model with low aerosol and GHG sensitivities can reproduce the data as well as a model with high sensitivities. As a result, the GHG sensitivity is today uncertain by a factor of three (as it has been for forty years), therefore enlarging the uncertainty in any projection of future climates.” (p. 6)

“Not knowing the state of the ocean decades or centuries ago makes it difficult to correctly choose the model’s starting point. And even if that were possible, there is no guarantee that the model will show the correct variability 
at the correct times.” (pp. 6–7)

“This proliferation of discordant models is further evidence that they are not ‘just physics’.” (p. 7)

Weather Extremes

“Contrary to the impression from most media reporting and political discussions, the historical data (and the IPCC assessment) do not convey any sense that weather extremes are becoming more common globally.” (p. 8)

Sea Level Rise

“… sea levels began rising some 20,000 years ago at the end of the last glacial maximum. They rose some 120 meters until about 7,000 years ago, after which the rate of rise slowed dramatically.” (p. 9)

“A signature of human impacts on sea level would be an increase in the rate of rise after about 1950, when human  influences started to become significant. Such a signature is not evident in the rate over the past century… in fact, the acceleration post-1990 is not statistically different from the (presumably natural) acceleration experienced during the 1930s. Given the observed variation prior to 1950 and the steady quadrupling of human influences since 1950, one must conclude there are other important drivers of sea level rise beyond CO2.” (p. 9)

“Consensus projections of global sea level rise through 2100 are remarkably discordant with local observations.” (p. 9)

“To realize a 1 meter rise by 2100, roughly the mean of IPCC projections, sea level would have to rise six times more rapidly (12 mm/yr) averaged over the rest of this century, a slope illustrated by the green arrow.” (p. 9)

Tropical Cyclones (Hurricanes)

“Despite considerable multi-year variability in these data, there is no clear trend. In fact, NOAA’s Geophysical Fluid Dynamics Laboratory posted the following statement in Spring, 2016: (p. 10)

“It is premature to conclude that human activities–and particularly greenhouse gas emissions that cause global warming–have already had a detectable impact on Atlantic hurricane or global tropical cyclone activity.… ” (p. 10)

Conclusion

“… the historical and geological record suggests recent changes in the climate over the past century are within the bounds of natural variability. Human influences on the climate (largely the accumulation of CO2 from fossil fuel combustion) are a physically small (1%) effect on a complex, chaotic, multicomponent and multiscale system. Unfortunately, the data and our understanding are insufficient to usefully quantify the climate’s response to human influences. However, even as human influences have quadrupled since 1950, severe weather phenomena and sea level rise show no significant trends attributable to them. Projections of future climate and weather events rely on models demonstrably unfit for the purpose. As a result, rising levels of CO2 do not obviously pose an immediate, let alone imminent, threat to the earth’s climate.” (p. 10)