I recently got the following brief statement in  an email touching on politics and the war:  "Shouldn't we work towards keeping our planet habitable? It is high time."
    Which inspired the following—with this caveat:  it is not the result of research.  It's grown from things I've observed or read over a number of decades, AND includes what I've assumed from those observations.
We've been working at keeping our planet habitable for some decades now: reclamation of abused landscapes in the Upper Great Lakes Region and Appalachia by large-scale forest replanting beginning in the 1930s; air scrubbers on industrial smokestacks after World War 2 in some severely air-polluted cities.  And many remember the god-awful LA smog of the 1960s, and the noticeably better (though less than good) air of the late 1970s and into the 80s (I left there in 1985)... And old-timers who knew Lake Erie in the 1930s, and its big-time degradation after the oil refineries were built upstream on the St. Clair River in -- I believe the mid or late 1950s —on ex-Indian land bought or leased by Big Oil —may recall the scope and good results of the cleanup. 
    The collapse of raptor populations due to widespread, more or less indiscriminate 2-4D spraying, was followed by their strong recovery after 2-4-D was outlawed. 
    By 1950, gray wolves were virtually absent south of Canada, except for 150-250 in Minnesota and 2 packs on Isle Royal.  Today, wolf populations are well reestablished in a number of western states, and in Michigan and Wisconsin where they'd never been entirely eliminated.  In Minnesota they number something like 3,000 now, boosted by protection, and by migrant Canadian wolves, who don't grok borders.  And in turn, migrant wolves from Minnesota helped recovery in Wisconsin and Michigan.

    Just a few examples to illustrate progress.  Lots left to do.  Even Dubya pays lip service to the need.