Global Warming, "The Sky is Falling", and Comparing Mars

I'm guessing "The Sky is Falling" effect will be in the form of heat.  The atmospheric layers will still exist, just as with Mars.  The surface will be the coolest, (or the warmest), while the upper layers will be hotter - Earth and Mars can be compared this way now.  I'm afraid without significant amounts of oxygen to protect the surface, and considering the amount of gasey pollution we create, I have to believe, we'll end up just like Mars if the power people are not serious in changing the way "business" is done.  My opinion is that the tools to measure all the atmospheric layers, especially the upper layer where it is the hottest, have not been around long enough to show solid data of earth's possible global warming.  I hate to think that by the time the temperature changes reach the surface, it will be too late.  Anyone who thinks it's not possible for a planet to heat up, should take a closer look at Mars and the history it has that we on Earth could eventually repeat.