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Let’s face it. Trolls aside, global warming is a scientifically verified phenomenon. The question was first “Is it happening?” Our answer is yes. The next question inevitably becomes “Are we causing it?” Again, the science suggests that humans are at the root of AGW (anthropogenic climate change).

Slightly different numbers, same surprising conclusions

How can humans, a single species on this pale blue dot, cause such an atmospheric ruckus? The literature is hard to wade through if you are not a specialist, so let me use one example as to how human activity could be responsible.

CO2

As climate science has outlined, solar cycles, urban heat islands, and naturally progressions in the Earth’s climate are not to blame for the trends that we observe. One of the greatest offenders, the most obvious one, is the greenhouse gas carbon dioxide, or CO2.

Granted, green house gases are vital to our survival; without them the planet would not be warm enough to sustain us. However, produce too much green house gas and you get a “run-away” effect that ends up turning our atmosphere into one more akin to that of nearby planet Venus: a 900 degree (Fahrenheit) death zone.

So excess greenhouse gases like CO2 are the problem. For this to be a human problem, we would have to put out enough CO2 to have an effect. Unfortunately, this is exactly what we are doing.

An Inconvenient Chemistry

It might surprise you to know that every gallon of gas that you burn puts around 20 pounds (9 kilos) of CO2 into the atmosphere. But how could this be the case? How could a 6 pound (2.5 kilo) gallon of gasoline suddenly become 20 pounds of greenhouse gas? The answer, and the problem, is simple chemistry.

It seems impossible that a gallon of gasoline, which weighs about 6.3 pounds, could produce 20 pounds of carbon dioxide (CO2) when burned. However, most of the weight of the CO2 doesn’t come from the gasoline itself, but the oxygen in the air.

When gasoline burns, the carbon and hydrogen atoms separate. The hydrogen combines with oxygen to form water (H2O), and carbon combines with oxygen to form carbon dioxide (CO2).

CO2 molecule with one carbon atom (atomic weight 12) and two oxygen atoms (atomic weight of 16 each)A carbon atom has an atomic weight of 12 (meaning that a certain amount of these molecules, a mole, would be equivalent to 12 grams), and each oxygen atom has an atomic weight of 16, giving each single molecule of CO2 an atomic weight of 44 (12 from carbon and 32 from oxygen).

Therefore, to calculate the amount of CO2 produced from a gallon of gasoline, the weight of the carbon in the gasoline is multiplied by 44/12 or 3.7.

Since gasoline is about 87% carbon and 13% hydrogen by weight (an estimate from a main component, octane, C8H12), the carbon in a gallon of gasoline weighs 5.5 pounds (6.3 lbs. x .87).

We can then multiply the weight of the carbon (5.5 pounds) by 3.7, which equals 20 pounds of CO2!

The math, and the stoichiometry (chemistry-based mathematics), is rather simple but the implications are frightening.

Coming To Our Senses

Given that Americans alone burn 380 million gallons of gasoline every day, this amounts to over 7 billion pounds of CO2 being put into the atmosphere every day, just from gasoline, and just from American use! Can you imagine the amount that we have put into the atmosphere since the invention of gasoline?

The reality is that when you think about how much CO2 we put into the atmosphere everyday, from all over the world, by all the countries, from sources that are far more numerous than gasoline, humans are obviously the culprit of the observations we make about our warming climate.

Can we really think that this gargantuan amount of gas, which we know has a warming effect by itself, would not have consequences for our climate?

[Via FuelEconomy, Climate Change 101]