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I've been skeptical regarding research showing that the Hunga Tonga eruption had little impact on global average temperatures. It's probably time for me to throw in the towel. Hot off the press is yet another study showing no augmentation of the global average temperature. In fact, if anything, it may have slightly contributed a cooling influence. This is obviously more bad news for global warming since Hunga Tonga was a factor that some used as evidence against Hansen's accelerated warming hypothesis. [Shoeberl et al. 2024]

It looks like Las Vegas is on track to have it's hottest month on record. If the official NWS forecast verifies and assuming I added everything up correctly they will end with an average of 99.2 F which would beat 2023's record of 97.3 F. Personal note...My family is wrapping up a vacation in the region. We started in California's central valley and drove into parts of Nevada, Arizona, and Utah and are flying back to St. Louis from Las Vegas. It has been brutally hot the whole time almost everywhere except for the slight reprieve while in the mountains. Death Valley was particularly insidious. Atypical of the region it was actually modestly humid so the heat index matched the temperature when we drove through. We were confused as we approached from Lone Pine, CA seeing runners. After a bit of research we realized we were unintentionally spectating the 2024 Badwater Ultramarathon where 100 of the word's toughest superhumans race from Badwater Basin (lowest point in CONUS) to Mt Whitney (highest point in CONUS) and is considered the world's hardest foot race. I definitely tip my cap to those who participated in that race,

Dust bowl. It's effects were large and widespread easily encompassing the eastern states and impacting temperatures there. [Meehle et al. 2022]

I did a quick review of IPCC AR6 WGI chapter 5 regarding the carbon cycle. Based only off a cursory read I don't think they are expecting the land sink's ability to buffer carbon to wane until much later this century. So if we're already seeing signs that it's ability to take carbon is saturating then that's not good obviously.

That guy has a long history of contrarianism and misinformation. I give him credit for a testable prediction, but it's going to end up being wrong. BTW...it's ironic how contrarians flock to the idea that 150 MtH2O can cause so much warming while simultaneously scoffing at the nearly 100,000 MtCO2 that humans pumped into the atmosphere in the 2.5 years since the HT eruption. I'm not saying HT didn't have a measurable effect on the global average temperature. I've been pretty open to the idea that it may have. But to claim that it is the primary cause of the recent spike while suggesting that ENSO had little if any effect is absurd. I'm also disappointed with degreed meteorologists like @John Shewchuk who pop in from time to time on articles like that and in support of this kind of misinformation. John, having a genuine conversation with you is nearly impossible because of your challenges to fundamental and well established physical principals and laws, accusations that NOAA (who was at least at one time one of your customers) is wantonly committing fraud, and incessant gaslighting in general. I tag you here to give you the opportunity to defend yourself if you so desire.

Relevant to this discussion is [Menne & Williams 2009] which documents the pairwise homogenization algorithm. Like @chubbs said it is done for each station individually to identify the changepoints and quantify and correct the bias that it introduces. This technique was introduced so that GHCN (including USHCN and now nClimDiv) was robust enough to handle stations that did not have adequate metadata (like is available in the HOMR database) to know when significant changes occurred to them. Even in the US the HOMR database does not always capture every change to a station.

Can you give me an example of one of these ghost stations? I'd like to research that.

Relevant to this discussion is the way UHI works. UHI Effect - This is the increase in temperature as a result of land use changes. It is a real phenomenon. UHI Bias - This is the error that is introduced into spatial averages as a result of oversampling either urban or rural stations in a grid cell. This is not a real phenomenon. Instead it is an artifact of the methodology chosen. It is is really important to understand that while the UHI Effect is always positive the UHI Bias can either be positive or negative depending on which stations are oversampled. The movement of the Coatesville station to a more rural site introduces a negative UHI Bias on spatial averages. It is worth repeating and boldening. The UHI Bias can and often is negative. [Wickham et al. 2013] analyzed the bias UHI caused in the Berkeley Earth dataset. They concluded "We observe the opposite of an urban heating effect over the period 1950 to 2010, with a slope of -0.10 ± 0.24°C/100yr (2σ error) in the Berkeley Earth global land temperature average." This is statistically equivalent to no effect, however, if anything, it is more likely the effect biased the global average temperature trend too low. I'll point out that Berkeley Earth uses a unique methodology in which they do NOT perform any adjustments to station data and yet get essentially the same warming trend as every other global average temperature dataset.

With the June update the warming rates of nClimDiv and USCRN are +0.58 F/decade and +0.70 F/decade respectively over their overlap period. It is important to note that nClimDiv uses pairwise homogenization to identify changepoints and correct the biases they cause. USCRN does not perform adjustments of any kind. So for those who think NOAA's adjustments are the cause of the warming trend this is strong evidence that the hypothesis is false. In fact, the opposite may be occurring. NOAA's adjustments may still be inadequate to fully remove the low bias.

Yet another attribution study except for the 2022 (not 2021) heatwave in the Pacific Northwest. Anyway, the point is that these kinds of heatwaves will become 7.4 to 11.5 times as likely by mid to late 21st century. https://iopscience.iop.org/article/10.1088/1748-9326/ad5ab0

The final update for Las Vegas is 120 F.

Las Vegas hit 119 F breaking their all time record high. This is preliminary as additional warming may occur. I'll edit this post with the final high. Edit: 120 F is the updated high.

I'm not sure how I missed this one yesterday...Palm Springs, CA set a new all-time record high. 124 F.

Death Valley set a new record for July 5th of 127 F yesterday. All time record highs may get challenged today in California and Oregon.

And the NWS point forecast on the south side of Bad Water Basin at its lowest point in Death Valley is 132 F on Tuesday.