First, I am not a "global warming denier", but rather a skeptic of the accuracy and uncertainty levels being ascribed to global climate models - especially in their extrapolations beyond a decade or two. I am not even confident that thing won't turn out to be better or worse than currently predicted.
That said, I just found a paper (which I have not had a chance to fully read), that seems to have at least advanced our understanding of the astronomic drivers of the ice age cycles. See
https://www.nature.com/articles/s43247-023-00765-x . This seems to answer one of the questions, but we still have a long way to go to understand how the global circulation patterns change and affect local climates to produce ice sheets, etc. That is what we need to understand to better predict the rates of changes and their locations.
It still seems like we have a long way to go to make predictions of the future climate that are very reliable. That should not be any surprise to those of us who have been around for several decades and watched the evolution of our daily/weekly/seasonal weather prediction capabilities - they have improved tremendously, but still can't tell us with much accuracy a lot of the things we would like to know in our daily lives.
The problem is that we don't have time to make our models of future climate accurate enough that nobody can argue with the results. We do already have enough information to know that humans are affecting the climate, and what general directions those effects will have for the future, and that those effects will have negative consequences for a lot of humans, if not all of us.
And, that is just part of how human population has changed our environments and ecosystems. We are also losing species in another mass extinction, mainly due to habitat destruction by us, and polluting with all sorts of chemicals, that have lasting biological and ecological effects, much faster than we are realizing that those effects are occurring.
But, more significantly, humans are reacting badly to the increased population density of humans. (And, that was also a prediction made in the 1950s, with the first quarter of the 21st century predicted to become much more confrontational than usual.) That is a big part of the reason that we cannot control our effects on our environment. We are in conflicts with each other at many levels, and that blocks the trust that is needed not so much in science, but in each other, in order to form and execute the policies that we need to ensure our well being, and maybe even survival as a
technological species.
Those who are thinking that soon enough, we will gain the ability to travel to other planets that can sustain life without support from Earth are almost certainly wrong - for several reasons. Beyond the realities that there are no apparently suitable planets within the region that we have any hope of reaching with our knowledge about basic physics, we have the underlying problem of human nature, itself. That
goes with us even if we could find a "second Earth" and manage to transport a seed population of humans there. We would simply do there what we are doing here, with similar consequences. Even sustained "outposts" on Mars would, in multiple generations, eventually develop similar conflicts to those now on Earth, but in a much less forgiving and supporting set of environment conditions.
So, our only real hope for survival in the form we are currently accustomed to is to
change us so that we behave in ways that are sustainable here on Earth. That means reduce our global population, and find ways to sustain the reduced population that at least allow the Earth's climate and natural ecosystems to be insignificantly affected by our presence.
Yes, we would still be affected by climate changes that occur naturally. All life on Earth has to do so, and we are never going to be able to find ways to control the climate exactly to our specific desires. Even if we had not already changed the global climate into a major warming period, we would then be expecting a global cooling period that we would have needed to adapt to.
In the not so distant past, humans adapted by migrating to different areas when the areas they were occupying became unsuitable, or even just the local resources were use-up. But, as human populations expanded to fill the whole habitable parts of the globe, humans who needed to move found that they had nowhere to move to without overpopulating other areas, and getting into conflicts with those humans already there. Since we have gained the ability to record our history, it is full of conflicts between groups of people who have different life-styles and fight over access to land and water (and now, other resources like fossil fuels and minerals).
So, as a species, we are going to have to adapt to the concept that our environment has limitations that we need to accept to prevent our species' population crashing. (Population crashes in other species that have experienced large population spikes are
normal ecological occurrences, and are
expected.) The only way we should have any hope of avoiding such a collapse of our own population is that we are unusually "intelligent" compared to other species. But, are we "intelligent" enough? I hope so, but, right now, it doesn't look like a good bet.