Various estimates of world population put it pretty close to seven billion. Give or take a few hundred million. What the heck does that mean?
Ever go to a sports event in a large stadium? Fifty thousand people is a reasonable estimate for the the capacity of a good size stadium. Not counting cheerleaders. (Actually, going by the Wikipedia List of American Football Stadiums By Capacity, the average is probably higher, but fifty thousand is a nice easy number to work with.) The larger stadiums seem to hold close to 100,000 fans. So, for argument's sake, let's say fifty to a hundred thousand (plus the cheerleaders.)
So two stadiums (or one big one) hold 100,000 people. Picture the lines at those bathrooms! And that's only 100,000.
So ten times that ... ten or twenty stadiums ... is about a million people. Ten to twenty football stadiums full of chest-painted, big-foam-finger-wearing, beer-swilling fans ... a million people!
Now take those ten or twenty stadiums, and multiply by 300. Three to six thousand football stadiums. That's a lot of football stadiums. That's like having a football stadium every 25 to 35 miles all across and up and down the entire United States. Think about it. Anywhere in the U.S., you're never more than about 20 minutes from a football stadium And that would be just about enough stadiums to hold every man, woman and child in the U.S. Three hundred million people. All watching football.
Now three times that number, 9 to 18 thousand stadiums, that would be about a billion people.
And the world has almost seven times that many!
So is it possible, just possible, that all those people driving cars and flying jets, using TVs and computers, chopping down trees, eating food, burping, cheerleading, etc. just might have some impact on the world's climate?