Do you consider human actions a part of nature or separate from nature?
Very interesting question.
There is no denying that we are part of nature.
I think the last time nature produced anything with the sort of effect we are having is when oxygen producing bacteria (cyanobacter) evolved, and changed the atmosphere from one of mostly methane, ammonia and carbon dioxide to one of mostly oxygen and nitrogen. Completely changed the chemistry of both the air and the water, and restricted most of the then dominant life forms to a few restricted niches (those that weren’t forced to extinction).
As Brian says, we have a new mode of evolution, which is far beyond the ability of any of the older life forms to adapt to. It is up to us to raise our awareness of our relationships to everything else fast enough that we can save ourselves from any (all) of the looming disasters (ecological, biological, economic, astronomic, volcanic, technological).
I am certain we can survive, I am not certain we will. It will be a close thing, whichever way it goes.
Certainly we are natural.
Nature is simply life exploring the possible niches available for survival through various random and not so random processes of variation. We seem to be the highest level of that process to date on this planet (at least so far as we are aware of).
We are an entirely new form of life, going through a difficult birthing process to awareness and full understanding of our unlimited potential.