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Showing posts with the label john shewchuk

Pausa Revivida!

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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...

Satellite Data Tampering by John Shewchuk

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The graph below from John Shewchuk is intended to show that models predict too much warming compared to satellite data. Shewchuk claims that the red line is the average of 102 IPCC CMIP5 model runs for the surface through 50K feet. In all likelihood, this is just lifted from graphs of model-observation comparisons that John Christy has plotted in the past. Shewchuk claims the blue line is UAH satellite observations for the total troposphere layer (TTT). The problems with this graph are numerous, and many of the problems are inherited from Christy's graph (problems with his comparison are well-documented ). The two time series are separated from each other even in 1980 to exaggerate the differences between the two (even if the trendlines do intersect at 1980). The 102 model runs are not shown, only the model mean, and the 95% confidence interval is also not shown, so we have no idea what the spread in the model runs might be. But Shewchuk has added his own dishonest twist to this g...

Can Bray and Eddy Cycles Explain Global Warming?

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There's a  schematic  that is frequently promoted by John Shewchuk on X to claim thatt long-term solar cycles explain much more of temperature variability of the last 2000 years than changes in greenhouse gases like CO2. The implication is also frequently made that the current warming over the last century or so is due to these cycles and not to changes in GHG concentrations. One common version of this graph is here. The Hallstatt-Bray cycle, which has a periodicity of ~2400 years, and the Eddy cycle, which has a periodicity of 976 years, are both related to sunspots, and so they indeed do have an impact on total solar irradiance (TSI), and therefore they can in principle have an effect on global temperatures on millennial timescales. But the significant question is, by how much?  Astute observers will note that Shewchuk didn't include any scale for the y-axis; the impact of these cycles could be negligible or large as far as this schematic is concerned. I do find ironic,...

Data Tampering by Shewchuk and Heller

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If you follow climate discussions on X, you're bound to see John Shewchuk and/or Tony Heller show graphs that reportedly show that NOAA is tampering with temperature data to fabricate global warming with spurious warming trends. I've gone over many of the reasons why this is nonsense before in posts about bias correction and so-called  ghost stations . I think it's good to show what's actually going on with the graphs they present as "proof" of data manipulation, though. I think it can be easily demonstrated here that it's actually Shewchuk and Heller that are tampering with data. Shewchuk (Top) and Correct (Below) Above are two graphs. The top graph shows what John Shewchuk claims shows that NOAA is manipulating data. It shows USHCN "raw" and "altered" Tmax data for 1900 to 2023. The bottom graph above is the correct plot of NOAA's published data from the current and correct dataset ( nClimDiv ) with a 5-year running mean to m...

Can the Tonga Eruption Account for the 2023-2024 Warming Event?

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On January 15, 2022, the volcano Hunga Tonga–Hunga Ha’apai (hereafter Tonga) erupted. Normally, volcanic eruptions such as this send sulfate aerosols into the atmosphere that cause a short-term cooling effect in the troposphere (and warming effect on the stratosphere) for a couple years.  However, the Tonga eruption was somewhat unique in that it erupted in shall water and therefore injected 146 MtH2O along with 0.42 MtSO2 into the stratosphere.[1] The injection of water vapor into the stratosphere created the potential that this particular volcano might not cause the short-term tropospheric cooling normally expected. Ever since the anomalous warming began in 2023 (roughly coinciding with the onset of El Nino conditions), a lot of misinformation has circulated on social media that the Tonga eruption is responsible for the warming spike the globe is currently experiencing. This misinformation appears to come from 1) a misreading of one early study[1] that examined only the impact of...

Is Happer Right that Warming by CO2 is Too Small to Matter?

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In a recent talk  (relevant excerpt from John Shewchuk  here ) given to an Australian political group called the Institute for Public Affairs (IPA), William Happer argued that doubling CO2 causes only 0.71 K warming, and that amount of warming for 2xCO2 is too small to matter. He then suggests that in order to make CO2 a problem, scientists had to invent giant feedbacks to amplify warming by as much as 10x the amount caused by CO2 alone. I've seen this claim repeated by others on X and other social media platforms, but as best I can tell Happer originates this particular argument. So I'd like to consider, is this plausible at all? I think it's pretty easy to investigate this and show conclusively that it is not. In fact, even Happer disagreed with this claim as recently as 2020. Ranges for ECS/TCR in IPCC Reports Happer's Argument At about the 1 minute mark of the above linked excerpt, Happer explains his math on how he arrives at 0.71 K for equilibrium climate sensitiv...

Does NOAA have "Ghost Stations" for US Temperatures?

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The Epoch Times (ET) is a newspaper operated by the Falun Gong cult, formed in 1992. The cult is (understandably) opposed to the Chinese Communist Party, but recently it has made some inroads into the US, where it supports far-right political agendas; its ET newspaper has promoted a number of conspiracy theories involving QAnon, anti-vaccine propaganda, and climate science denial. In a recent " premium report ," the Epoch Times claims that the U.S. Temperature dataset operated by NOAA contains data from "non existent temperature stations" and asserts that there are "hundreds of ‘ghost’ climate stations" that are no longer operational, and data is just filled in from surrounding stations, with the implication that this is done to support Biden's climate policies. The tl;dr point here is that what the article calls "ghost stations" are actually just interpolated values used in calculated area-weighted means in an old dataset that NOAA no longe...

Correcting Contrarian Graphs on the Relationship Between CO2 and Warming

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It's well-established physics that the Earth's surface is ~33K warmer than its effective temperature, and the relationship between increasing CO2 and radiative forcing can be approximated by the following logarithmic equation: ΔF = 5.35*ln (C/Co) where, Co is an initial concentration of CO2 (preindustrial CO2 is generally regarded as 280 ppm).  C is the concentration of CO2 at any given time (currently 420 ppm). The equation shows the change in the outgoing flux at the top of the atmosphere caused by a change in CO2 concentrations. Since CO2 concentrations have increased by 50%, we can say CO2 has caused a decrease in the outgoing flux of 5.35*ln (1.5) = 2.2 W/m^2. As a result of this decrease in outgoing flux, more energy enters the climate system than escapes into space, and so the planet's surface must warm until the outgoing flux equals incoming again. The relationship between a change in radiative forcing and temperature is linear, so ΔT = λ*ΔF So essentially the relat...