For thousands, maybe even millions, of years there have been times when global events of great magnitude were severe enough to affect global climate conditions and weather.   There have been different global events, ranging from asteriod impacts, to widespread uncontrolled firestorms, or to prolonged volcanic activity that would have caused serious disruptions to the Earth's atmosphere and its weather patterns for a period of many decades.
    The point is that all throughout history "none" of these events caused "permanent" damage to the Earth's atmosphere.   After a period of time when the atmospheric disruptions and disturbances finally settled down, the Earth's atmosphere then had a "chance" to recuperate and return to normal.

    All of that has changed with the dawn of the "Combustion Age", however, because now there is hardly any chance that the atmosphere will ever return to normal.
    The good ole days of sudden catastrophes have been forever changed with the "steady" yet silent global catastrophe known as combustion: widespread global combustion on a scale that had never been witnessed before the turn of the last century.   Because, unlike the days of old there is absolutely no time for the Earth's atmosphere to recuperate and catch its "breath" from the constant, relentless onslaught forced out from the billions of combustion engines - ranging from vehicles, aircraft, and ships, to power plants - all around the world, always emitting toxic exhausts 24 hours a day.
    If you "compared" the overall damage caused by the tons of pollutants and harmful chemicals being thrust up into the air and its ozone layer by billions of combustion engines always running in "every" city worldwide, it would be "equivalent" to hundreds of raging forest fires, but without the visible smoke, spread all around the world and burning out of control, nonstop.

    This constant "nonstop" combustion is causing "permanent" damage to the Earth's atmospheric conditions and weather patterns.
    Mankind must either voluntarily stop this uncontrolled "smoking" or we all will continue driving on towards a "certain" future apocalypse.   You can prove the certainty with this mathematical equation:   (x)+(y)= z.   (Steadily increasing amounts of carbon monoxide and "carbon dioxide" increasing towards doomsday because carbon dioxide is mainly absorbed by trees which are all disappearing rapidly.) + (Steadily decreasing amounts of "oxygen" which is mainly being released by trees decreasing to the point of zero.) = certain mass extinction.   About the only way that certain mass extinction can be avoided is by switching the variables within the equation around.   As of right now, the way that the present world economy is structured, fifty percent of all trees will be gone within a century in order to keep pace with the global "construction" of buildings.   Many more will need to be built in the future to provide enough "indoor" space for the inevitable population increase in an already overpopulated world. (A sad result of a religious society that was commanded by their God, "Be fruitful and multiply on the earth and increase upon it as the sand which is upon the sea shore.")
    Until the whole world economy is dramatically restructured I can only see disaster ahead.   That is unless you honestly think that the forests of the world will be able to always provide hundreds of lumber companies with an endless supply of wood without ever affecting our shared biosphere.   I am very concerned that it just cannot work that way.   I know that a serious global catastrophe is now developing and may actually strike within a century or two if the nonstop global combustion plus the global lumber destruction stays the same.
  [* Beware, if global warming isn't slowed nor stopped then it will get too hot outside, sooner than later!   My prediction is that in August, 2100, the temperature on the hottest, summer day in Dallas, Texas will reach 120°F outside.  That means that the hottest, summer temperatures in desert cities will be much hotter, and hot enough to cook people alive!  Until global warming is halted then one sure event can be predicted:  Early in the 22nd century, on the hottest, summer days above 130°F outside, people must wear some protective, air-conditioned space suits when they go outside, or else they will get cooked! *]   But, I am an eternal optimist.   I will never give up hope because I know that there is a bright side to everything.

    So, here is some good news.   I do know that it is possible to steadily decrease carbon dioxide emissions with enough folks "getting involved" to reduce their usage.   I also don't see why we all can't plant millions of trees with enough folks "getting involved" and to eliminate unnecessary construction within uninhabited wilderness.   However, that is the whole world's choice to make.   This is a global problem and it can't be solved without everyone's complete mutual cooperation.   The one human-produced problem (spray-can propellants, etc.) that may not be solved is the ozone hole, which is a region in the upper atmosphere where there is severe depletion of the ozone layer that protects life on Earth by blocking the sun's ultraviolet rays, because it keeps getting bigger every year.   Either way, the damage has already been done and it will take a very long period of recuperation before the Earth can ever be healthy again.