“By ‘climax’ I guess you mean systems …”
A common definition: “An ecological community in which populations of plants or animals remain stable and exist in balance with each other and their environment. A climax community is the final stage of succession, remaining relatively unchanged until destroyed by an event such as fire or human interference.”
For an introduction to a more nuanced understanding, see https://en.wikipedia.org/wiki/Ecological_succession.
“how the limits of a system are defined”
For example, see https://en.wikipedia.org/wiki/Ecotone.
I have a young friend who has been exploring this concept in relation to architecture (see, e.g., the abstract on pp. 52–53 in the pdf at http://eurau2016.uauim.ro/dld/EURAU2016%20Abstracts.pdf). I think the concepts he is developing are potentially very fruitful.
“a realistic view of how interrelated life on the planet really is”
On this point, if you are not familiar with the work of Makarieva and Gorshkov in St. Petersburg, you might find the website http://www.bioticregulation.ru/ interesting. In addition to the role of life in affecting climate from the micro to the global scale, I find their work on the information processing aspect quite interesting: “Information fluxes that are processed by the natural biota while performing environmental control exceed the information fluxes that modern civilisation would ever be able to process by twenty orders of magnitude. The biotic mechanism of environmental stabilisation is unique and cannot be replaced by a technological one.”
“there are no sophisticated recording technologies like writing outside of humankind”
I view the invention of the RNA/DNA system a few billion years ago as the first invented written language. The human invention of written language is very recent in the history of humankind. There is a saying “Necessity is the mother of invention.” I think it is not true (I have invented many things that very few people have ever heard about, and most of those who learned about my inventions have probably forgotten what I told them). Influenced by Mike Meyer’s reported experience, I now incline toward the view that “Perceived necessity is the mother of the adoption and spread of an invention.” The adoption and spread of written human languages seem to be associated with necessities created by civilization (cities).
Regarding “industrial” technologies, I offer an analogy to a natural sequence: a relatively massive introduction of a limiting “nutrient” into an ecosystem leads to a population bloom of a species or associated group of species, which in turn leads to a population crash and the formation of a dead zone. An example of such a sequence is the introduction of nitrates and/or phosphates into an aquatic ecosystem followed by an algal bloom and the formation of a dead zone. Another example might be the introduction of fossil carbon (coal followed by oil and natural gas) into the global ecosystem followed by a bloom of humans and associated domestic animals. You are probably aware of some estimates that humans and their domestic animals now constitute about 97% of mammalian biomass on the planet (a “bloom”). I hope we can appropriately anticipate the expected dead zone following such a bloom. (Here I intend a particular meaning of “to anticipate”: to forestall or nullify by taking countermeasures in advance.)