First, I agree with @davbart - Healthy skepticism is a good thing.
It’s true that the Earth has experienced cyclical warming and cooling throughout history, It’s also true that we are now in an inter-glacial warming period that began 10,000 - 12,000 years ago and is independent of human activity. Yes, climate is always changing; it’s the rate of change since the mid 20th century that doesn’t fit geo-historical norms. The concentration of CO2 in the atmosphere was about 280 ppm for a thousand years up to 1880. It rose slowly to 320 ppm between 1880 and 1966, then much faster to 421 ppm by 2022. I’m not aware of an explanation other than human activity for this rapid rise in atmospheric CO2 and the parallel rise in global mean temperature. Could we eventually discover that accumulating greenhouse gasses and/or other source(s) of global warming are unrelated human activity? Perhaps, but it’s not a bet I choose to take. When my granddaughter’s generation asks how we could have left them such a mess, I won’t have the answer but I will be able to say that I did what I could.
Here are some scientific data you may not be aware of. The theoretical maximum human survivable wet-bulb temperatures were considered to be 95°F at 100% humidity or 115°F at 50% humidity for 6 hours. Recent studies at Penn State showed the actual survivable wet-bulb temperature was lower at 87°F at 100% humidity for healthy individuals in their prime and would be lower for older and health compromised individuals.
This number is the upper limit for our species There are places on the planet that have an average temp of 86F. Areas with those types of average temps will be increasing given the current levels of atmospheric CO2.
I agree a topic/problem spanning eons is likely not valid in a book written a couple years ago. The IPCC has been around offering advice and it was founded in 1988 and has a variety of reports changing year to year.
We lived in Houston for 8 years and it probably only felt like 95/95 for months. We had a small tropical garden outside our kitchen window. Every night the green peepers would be all over the windows. A garter snake lived somewhere around the front door.
Glad to know. A level dialogue is a good thing.
Keep the Open side up.
Pag
I have a question for the more knowledgeable here.
Why do we not see more data from ground temp year to year like we see data on water temp?
If we were to say measure the temp in remote areas on the earth at a depth of 30-40’ it would seem we would get a very stable measurement year to year at the same day and time. You wouldn’t want to go real deep where you get into the earths core temps moving outward and not so close to the surface that daily weather would be a factor.
With ocean water temps like air you are dealing with a constantly moving fluid complicating the problem. It seems to me if the earth temp goes up 1.2C over long periods of time the ground 40’ down should heat up 1.2C.
By long periods of time do you mean 10s, 100s, 1,000s of years?
Once you get past about 6 feet of soil the temps stay rather constant. It is due to what I would call insulative property of soil. Going even deeper and the temp stays constant across the seasons. The latitude has some effect on the below surface temps. Think of the Space shuttle’s ceramic tile heat shield and you can see how effective a thermal barrier can be made of primarily silica (sand) that withstands over 2,000F.
Here is a quote from a google search.
“the temperature fluctuations at the surface of the ground are diminished as the depth of the ground increases due to the high thermal inertia of the soil.”
Add water to the soil and it can change temps vertically more quickly than dry soil, and permafrost can be as much as half a mile deep or deeper.
What is the relevance of soil temperature depth change to climate change that you feel may be of importance? One that is viewed as relevant is the thawing of the permafrost (frozen wet soil with large amounts of organic matter) which is releasing vast amounts of methane and CO2.
(7) Is PERMAFROST the Climate Tipping Point of No Return? - YouTube
To add a bit to what Castoff said, here is a link to geothermal heat pumps that discusses a bit about how the ground temperatures fluctuate. The main reason geothermal heat pumps are so much more efficient than the more common air heat pumps is that ground temperatures are so much more stable.
Ground source heat pump - Wikipedia
As to why not see more of that type of data reported, it in part depends upon the question being asked.
If one is asking “Can we see the same effect of climate warming in ground water data?” or something along those lines, you might find more data sets doing just that. But if the question being researched is “How stable is the temperature underground?”, that may have been done already, the answer confirmed, and the research is considered well informed and there is little need for further examination. I have no idea if either of those possibilities (or other ones you might think of) is the case, just giving a potential answer for pondering.
I can say that in my field of wildlife biology, people asked that type of question a lot. “Why don’t we see more data…” “Why don’t we know how that correlates…” “Why hasn’t anyone looked at that…”
So many questions, so little time and resources available…
When I dive into Lake Erie on a nice summer day I can feel the water temp change as I go deeper to say 10’ I wouldn’t be surprised if it was 20f cooler down 10-12’, and after a storm and the water has been mixed there isn’t that change feeling. Air is the same I have seen days here where the temp swing can change 40f in an hour. These things are weather and not climate change IMO.
If I’m trying to judge the warming of the planet year to year it seems I would want a massive heat sink something that mitigates the short term affects of weather and measures the averaged temp by letting the mass adjust. To me undisturbed soil would maybe be a closer match to that than water. Maybe the way to do it would make a giant cast iron ball 50’ and place it in the shade and let it acclimate to the temp of the earth at that location. Once it was stable measure its temp in the center and then wait a year and see if it has warmed. Statistically if you want record it every day or even constantly but take all the variability out of it by letting it react on its own.
Like I said I’m not a scientist but as a simple man it seems to me if I’m looking for a very small change of 1.2C in 10-50 years or such and I’m aware of the concept of significant digits in scientific data. I can see where the variability of air or water temps can negate any experiment. I guess there are satellite things they are now doing to do actual measurements somehow. Even the sun is not a constant heat source as I have read where solar activity was the likely cause of the little ice age.
It seems like with all the trillions of dollars being put forth to solve climate change someone would be conceiving a system of say a giant world thermometer. Maybe why people are skeptical is we not really being shown measurements but rather being shown effects and predictions of effects.
If the ground temp 12’ down remains a nearly constant temp and I believe this to be true as I have a friend that built a below ground home that uses almost no energy to keep at 72f year round and overheats if he has 6 people over for the day. At some point are we going to have to go underground to survive, and why is there no push to go down with buildings now.
At my old home of 40 years when I bought it I put in a new well that held around 80,000 gallons of water and was imposable to pump down with normal a normal pump running 24-7 and would recover quickly. Winter and summer the water was very cold and I still had access to the old well from in the basement. I always wanted to but never did was to build a simple heat exchanger taking water from the new well and discharging it to the old well for AC of the house. The only reason I never did it up on the Great Lakes we really only have enough hot days to warrant AC you could count on both hands. A tiny window unit was all we needed in the bedroom. I had thought a little about a ground water heat pump but never did that as well.
Most of the climate science I read talks about the oceans being a great heat sink but it would seem to carry thru that the earth mass has to be factored in as well and as the bottoms of the oceans are in contact with the earth land mass and waters circulate. That and the area covered in land has to be sinking heat also. So again not being a scientist shouldn’t the land mass be a measure of global warming and a much more stable one than air or water to remove the variable of weather. I get that permafrost and water in soil is a factor and if there is greenhouse gasses trapped in frozen soil there are going to be outgases if they thaw. Heat travels from warm to cold and is always going to try and equalize. It is that total system equalized number that you would ideally measure and watch for a change I would think.
They have done some sustained underground measurement in some of the permafrost regions. I saw somewhere data showed it has risen in the summer from -3 C to -1C in a matter of a couple of decades. Of course, those reading are location dependent. Zero C is the freezing point. There wouldn’t be much value to measuring something you know won’t change on a time scale that would have much to add to what is happening rapidly in the moment. They are already measuring with accuracy the changing planetary temps where it matters most the surface of the planet that harbors life.
We may have to go underground who knows? If we do, will we become “Morlocks”? 
Unfortunately, there are enough in congress who would rather hold tight to their opinions than risk being proven wrong by data, so they choose to block funding for research that might lead to answers they don’t like.
There’s an easy measurement: world average temperature. These are simple measurements that have been taken constantly all across the world, for decades. This shows clearly the world average temperature rising. You don’t need to build giant iron balls.
Sometimes the simple answer leads to the truth.
Ask yourself: Who stands to profit from climate change denial?
They are. It is just a lot more sophisticated and involved than what you are proposing as a simple methodology. given how often one hears that climate science is complex, I think it is very reasonable to see a more sophisticated “global thermometer” as a good thing. The IPCC report covers just this notion.
It seems you are looking for a way to find a measurement that refutes or confirms the current scientific consensus. That is a valid thing to do in science. But any impact of climate change on the earth 40’ underground won’t show a change in any useful time frame. The earth 40’ down has very little measurable impact on climate that I know of.
The speculation you present is called a hypothesis. That is a valid part of the scientific method. It has to be tested before it’s accepted to have any kind of validity. Otherwise, it falls into a strawman type of argument. The obvious things that impact climate change are being actively measured. It is unfortunate that they aren’t to our liking.
To try and put this in perspective let me ask a question. Would you knowingly pick a thermometer that would take a week or a month to measure your temperature if you had a fever? The other question is what reasonable benefit would that be for you?
Who is denying climate change? Additionally, if you’re going to assign motives to this supposed “denial” then you should apply the same standard/skepticism to those who are using climate change to enrich themselves and gain political power and influence.
Of course as soon as there’s governmental money backing energy-saving initiatives everyone jumps on to try to profit, regardless of politics. But 10, 20, 30, even 40 years ago, before this existed, or at least existed to such an extent as it currently does, there were scientists saying it was happening and plenty of people denying it and attempting to stifle them.
More like 50 years ago. We talked about human input of carbon into the atmosphere in ecology class in the early 70s. That was before there was much public awareness of the issue. I have seen that Exxon and other oil companies also knew about human caused climate change back then. Government funding for much basic research dropped way off in the early 80s due to the recession.
But yes, money drives most people for both good and bad reasons. The higher the sums the more ethics and morality seem to suffer. That would tend to imply the greater the sums the more likely the resistance or the implementation of change depends on that balance. Science that doesn’t directly lead to profits often takes a back seat to money.
So, why the question? Frankly, most of my skepticism isn’t about the data/science as much as about the level of threat it poses, effectiveness of proposed policies, and yes, the motives of those who exploit these things for political and financial gain.
I will say at this point, I’ve been on the periphery of this thread because of this turn. It becomes a political debate at some point, and I’m pretty sure no one wants that on a paddling site.