Today we took our understanding of global warming to the next level, a more real level. Students did an experiment where they compared the CO2 content in five different samples of air: indoor air, outdoor air, human breath, air from burning wood, and car exhaust. By injecting the air through limewater, which reacts with CO2, they were able to actually see which samples contained the most carbon dioxide.
Most groups found that — no surprise here! — car exhaust had the highest amount of CO2. And human breath had a lot too. But that doesn’t mean human breath is contributing to global warming. The carbon from human breath comes from our food, which starts off as a plant, which gets its carbon out of the air in the first place! That’s no problem at all. But when you take carbon that’s been trapped underground for millions of years (oil, coal, natural gas) and you burn it, you are adding greenhouse gases that the living creatures on Earth just aren’t ready for. The problem with CO2 is not that it’s evil, it’s that all of a sudden we have too much! And our warm, comfortable planet is getting hotter by the day.