I don't think so, but the people who express disdain for the impact mankind has on the environment-in evidence here-aren't helping. Ever since Carson McCuller's 'Silent Spring' sparked the environmental movement there has been resistance to virutally every initiative taken to protect the environment, usually spearheaded by corporate and business interests who claimed that being made accountable for their impacts on the environment would bankrupt them, and a vocal contingent of individuals who bought into that as well as objecting to having to pay the costs of advancing technology, generally on the basis of freedom and liberty. Freedom to pollute wantonly, for example. But like one of my favorite conservatives once said, "Your freedom ends at the tip of my nose." That's a double edged sword for most of us, true...but if one person claims that not being able to toss his garbage in the river impinges on his "freedom" ten more who live downstream are going to object to that freedom-loving guy defining freedom strictly to his own advantage and thinking that gives him the right to define liberty for others. We see this attitude shot through democracy-especially in the United States-and in point of fact, it is this attitude in and of itself that brought forth the Magna Carta, the Declarartion of Independence, the U.S. Constition, the Emancipation Proclamation, and the Civil Rights Act, just to name a few efforts to define freedom and equality. The environment is no exception.
To be sure, there will always be those who will push the envelope on either side of the equation; people who will try to block reasonable progress on arcane environmental considerations, and others who will sometimes even deliberately pollute more in what they imagine is some sort of civil disobedience...the at least stated intent to consume and pollute more has been in evidence here repeatedly, in fact. But that is like shooting oneself in the leg to protest gun legislation.
Regardless, technology marches on, and while it does not resolve all the problems, it does address many of them, and is continuing to do so today, albeit with diminishing returns at this point. We see the development of alternative energy, now in its infancy but gaining ground as the efficiency improves and the infrastructure to distribute it is being built; we see progressive methods of farming improving efficiency, decreasing the environmental impacts of farming and yielding greater profits than ever for those who implement them; we see people first grudgingly accept things like recycling because it takes more time than simply dragging three bags of garbage to the curb every week to be landfilled, then seeing the benefits of it, and we see prototypical efforts to generate energy from landfill deposits producing energy on larger and larger scales.
I don't have an answer for deforestation and many of the issues you raise in your question, I am not an expert, and I do not have a crystal ball to say definitely yes or no insofar as what our global environment will be like in 40 years. I suspect that many millions of people around the world will be directly impacted by our habits and routines now, and others downstream-perhaps one could say some of us are downstream of ourselves-will be indirectly impacted by environmental changes. But I think it is an exaggeration to say that our environment will be 'mostly destroyed' in 40 years. I think we have more time than that...and the more pressing issue short term is to avoid an economic and geopolitical global meltdown, since the scale of the problem requires the coordinated efforts of many peoples and countries around the world. We've seen what happens when countries and governments descend into chaos and dictatorships.