Posts

Showing posts from July, 2025

Disappearing Glaciers in Glacier National Park

Image
What Remains of Agassiz Glacier in GNP Sometimes well-meaning people shoot themselves in the foot. Somebody at Glacier National Park put up signs indicating that all the glaciers in Glacier National Park would be "gone by the year 2020." Sign at GNP The strange thing about this is that the statement wasn't accurate even when the signs were made. The  reference to "computer models" refers to a paper published in 2003[1] that made predictions under two scenarios regarding a subset of the glaciers in the Blackfoot-Jackson Basin of GNP, with one scenario "based on carbon dioxide–induced global warming and the other on a linear temperature extrapolation."  The Area for the Modeling Study To evaluate how well this model has performed, it's important here to understand how these two scenarios were defined. I'll quote the paper's definition of each. Scenario 1: "The carbon dioxide–doubling scenario, is based on the US Environmental Protection...

Holmes on the Relationship Between TSI and Temperature

Image
I was just made aware today of a paper published in 2019 by  Robert Ian Holmes on the Relationship Between TSI and Temperature at 1-Bar Pressure. The paper claims to be able to "predict" planetary temperatures at 1-bar pressure on the basis of TSI values of rocky planets and moons with a surface pressure of 1-bar or higher. The logic is that if you calculate the relative TSI between two planets (rTSI) you can multiply ∜rTSI by the 1-bar temperature of one planet to get the 1-bar temperature of the other. We can summarize his math as: T1 = ∜rTSI*T2 There are three rocky planets and moons that have as surface pressure of 1-bar or higher. Here they are with Holmes' values for their 1-bar temperatures: Venus (340K), Earth (288K), and Titan (85-90K). Holmes shows his calculations below. This superficially looks convincing, but astute observers likely have questions, like 1) Are the empirical values accurate? 2) Holmes only did half the possible calculations with this data. Wha...

Forcings for Doubling CO2

Image
At least as far back as Myhre et al 1998 [1], scientists have understood that it's possible to approximate the effective radiative forcing (ERF, the amount of change in the outgoing energy flux near the tropopause) by a simple logarithmic equation: ΔERF ≈ α*ln(C/C0) I say "approximate" because the actual calculations for the relationship between ΔF and CO2 from line by line radiative transfer models are a bit more complex than this. The above equation is simply the result of curve fitting that matches those calculations over the range of CO2 concentrations that we're mostly concerned with. The value for α scales the radiative forcing change for the log change in CO2 concentrations. Myhre's value for α was 5.35, and this was used in the IPCC's TAR and AR4 reports. More recent IPCC reports, though, have improved the ΔF2xco2 estimates, and we can solve for the α values implied by these changes in ΔF2xco2 with α = ΔF2xco2/ln(2) ΔF2xco2 ≈ α*ln(2) AR3: 3.71 ± 0.4 W...

How Accurate are Our CO2 Ice Core Data?

Image
The Keeling Curve I sometimes hear claims that our measurements of CO2 concentrations, especially as recovered in ice core data, are unreliable indicators of variability in CO2 concentrations, often stating that CO2 may have varied by far more than scientists are letting us know about. The implication is that scientists are covering up evidence for the variability of atmospheric CO2 concentrations to sell a narrative that humans are responsible for the increase in CO2. There are at least two forms of lines of argument here, one arguing that ice core data is unreliable and the other arguing that other measurements of CO2 contradict the ice core record. 1. Zbigniew Jaworowski It appears that even in the 1990s there were attempts by contrarian scientists to undermine the reliability of the empirical data extracted from ice cores to reconstruct background CO2 concentrations over the last several hundred thousand years. One such paper, Jaworowski 1994[1], argued that the CO2 data was unreli...

Pausa Revivida!

Image
Back in January 2025 , I mentioned that since 2025 was expected to trend towards La Niña conditions we would be less likely to see another record-breaking year like we had in 2023 and 2024. And then I said contrarians would likely pivot back to the rhetoric they used following the 1998 and 2016 El Niño events: And since La Niña conditions are expected to develop in 2025, it's doubtful that 2025 will be another record-breaking year, so we should expect contrarians to pivot again back to the same kinds of fake arguments they used after 1998 and 2016. They'll start counting the months for which we've seen no warming while ignoring the fact that we should expect La Niña years to fall below the overall trendline and El Niño to land above it. I don't think anyone following climate discussions on social media would be surprised that this prediction is already showing itself to be accurate, and I'm sure there are many others that made similar predictions. But now on social...

Correcting for Time of Observation Bias

Image
You'll frequently see contrarian influencers on social media showing the differences between "raw" and "adjusted" temperatures for the United States that indicate that CONUS warming in the "adjusted" temperatures is greater than in the "raw" data. We're often told this indicates that scientists have adjusted CONUS temperatures to make them cooler in the past, thus making the amount of warming that has occurred in the US larger in the "adjusted" temperature data than in the "raw" data. It's then frequently just assumed that this is because "liberal" scientists need are conspiring with nefarious intent to tamper with and manipulate temperature data to create artificial warming trends in US temperatures. In another post I share some dishonest way in which contrarians exaggerate the difference between the "raw" and adjusted temperatures, but even in properly plotted comparisons, the final "adju...