"According to the analysis, if the world warms by 2C, which could happen in about 20 years' time, then the chances of having a heatwave similar to last week's drop from around once every 1,000 years to roughly once every 5-10 years. "
Apparently you haven't been paying attention to all the failed predictions by alarmists over the past 3 decades including:
The End of Snow (2000) https://www.climatedepot.com/2018/01/04/flashback-2000-snowf...
The predictions of Glacier National Park being ice free by 2020:
https://www.cnn.com/2020/01/08/us/glaciers-national-park-202...
Not only is it extremely, extremely unlikely that 2C warming is experienced in the next two decades, it is completely counter to the trend: http://www.drroyspencer.com/2021/07/uah-global-temperature-u...
All of this article is based on flawed computer models of non-linear dynamic systems that become exponentially unpredictable as a function of time. What were the odds of the 1930s heat waves, which were far more drastic, and far more sustained? No answer there.
"Overall, we rate the Climate Depot a strong Pseudoscience source based on the promotion of human-influenced climate denialism propaganda and the use of poor sources who have failed numerous fact checks."
I'm not sure how an anecdote of one climate prediction failing (your CNN article) is a rebuttal against decades of climate research and unanimous consensus from the vast majority of scientists.
As for Dr. Roy Spencer—his credentials are impressive, but he is just one scientist. The scientific consensus on climate change is established, and "nearly all actively publishing climate scientists (97–98%[3]) support the consensus on anthropogenic climate change"[0]. I don't particularly care for the opinion of one lone man.
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[0]: Anderegg, William R L; Prall, James W.; Harold, Jacob; Schneider, Stephen H. (2010). "Expert credibility in climate change". Proc. Natl. Acad. Sci. USA. 107 (27): 12107–9. Bibcode:2010PNAS..10712107A. doi:10.1073/pnas.1003187107. PMC 2901439. PMID 20566872. https://doi.org/10.1073%2Fpnas.1003187107
Same thing happened with Galileo - I'm not saying anti-climate change perspectives are tantamount to Galileo, but it's precisely that line of thinking that marginalized and abused countless (correct) counter-orthodox scientific arguments.