In a response to Setanta, you said it’s false to presume climate can only heat up in the absence of humans.
I don’t see where Setanta presumed that.
Setanta posted the following:
I would like to point out that the climate is changing and will continue to warm without reference to humans. Certainly human activity accelerates the effect, but the climate had been warming and will continue to change whatever humans do.
How in the world can you interpret what Setanta said in that quote as “climate can only heat up in the absence of humans”
? That’s not what he says. That’s not even what he suggests. I submit that the problem here must be your reading comprehension. That is, unless you’re just intentionally misrepresenting what was said.
He's saying that the climate is warming with or without humans, and humans might be accelerating it but that it would happen either way.
I was just pointing out that climate can either warm or cool (or both simultaneously in various ways) in the absence or presence of humans, depending on how the various parameters govern the energy/heat dynamics of the system(s) involved.
Really, we need to start seeing the climate as part of the larger planetary energy dynamics, and analyzing human activities in terms of how they modify natural patterns that occur in the absence of humans.
For example, when you clear an acre of forest and plant an acre of fruit/nut-bearing trees, that replaces carbon-absorbing trees with carbon-absorbing trees. When you clear the acre and let grass grow to pasture animals, you are replacing one kind of carbon-absorbing land-cover with another, which has different energy dynamics; and likewise if you plant trees for timber, that sets up yet another kind of energy/carbon dynamic.
All the above land-uses are different from clearing an acre and building a parking lot and/or buildings with little to no live canopy to reflect sunlight and absorb CO2 into its wood trunks and roots. Likewise, if you build a wooden structure, that sequesters some carbon by preserving the wood, but if there aren't living trees rooted in the soil there, you're not going to have the same quantity of carbon stored up underground after centuries/millennia of time pass.
Then, once you're thinking at the time scale of centuries/millennia, you can think about the build up of fossil fuels. Tar sands oil is found at between 1000 and 2000 feet underground. Coal can occur at all sorts of depths.
How long does it take biological sediments to reach those depths and levels of compaction/density of energy/carbon?
Taking these fuels out of the ground and converting them into CO2 vastly increases their volume. Tree canopies are like cast-nets for atmospheric CO2 that condense the carbon by converting it into sugars, cellulose, and fats. Trees and other plants feed those carbon products to animals, fungi, etc. so they eventually build up in the ground. It's a very slow process, but it works well over time because it is extensive instead of intensive; i.e. it is better than trying to run around sucking CO2 out of the air artificially and compacting it into some kind of denser form devoid of the energy that fossil fuels contain, because those fossil fuels surely play a role in the larger geological processes of the planet.
We are still viewing geology as separate from climate science, but if you think about it they are just two different layers whose energetic processes function in very different ways. Nevertheless, the oceans and biosphere, as hydrological systems that foster living matter, are part of both the climate and the geological processes, so they must be interconnected and interact in the overall mechanics that naturally distribute and manage energy throughout the planetary system.