I've been thinking about challenges to American hegemony.
While most of the discussions of this type focus on clear and present dangers, I've been thinking of some very long run effects that have non-linear consequences. "Tipping point" effects, where we cross a threshhold.
Some of them are end quarternary event scenarios, the kind where many eons from now intelligent cockroaches find our fossils and hypothesize about how we lived.
But others are a bit nearer to now, including how we interact with the environment.
Let me start by saying that there are very few poeple I've listened to who is making sense. If you have heard someone who is making sense, let me know.
Here are some things that I do accept:
1. The earth is getting warmer. Let's not talk about why just yet, but I can accept as fact that the earth is getting warmer.
2. This creates winners and losers, but on the whole more losers than winners; it is a general bad thing.
Um, that's about it.
There are a few challenges that I have about the generally accepted theories of global warming, like the causes.
First, CO2 is a greenhouse gas, sure, and so is methane...but water vapor is far more effective at creating a greenhouse effect. We do lots that puts water vapor into the air, yet no one seems concerned. Do we even know anything about historic levels of water vapor? I don't know, but I'd like to know. And I think that water vapor is probably partly to blame for rising temperatures.
Second, we burn some quantity of fossil fuels each year. The combustion of these fossil fuels generates heat. What if the amount of heat is non-trivial? If that was the case, then cutting our greenhouse gas emission might only be part of a solution. How much is this heat?
Third, how much biomass is in the oceans? Biomass soaks greenhouse gasses. What if the amount of biomass we remove from the oceans is so vast that the oceans can no longer sink greenhouse gasses - or if the biomass we want lives best at a temperature lower than the oceans are becoming? What happens if the oceans become biologically dead?
With all of these thoughts in mind, I did a hypothetical calculation on how many trees you'd need in order to sink the carbon output from your car. It was a quick calculation, full of assumptions.
I assumed that you drive 25,000 miles a year.
I assumed that your car gets 35 miles to the gallon.
I assumed that you'd choose to grow conifers.
I assumed that the trees were 60 years old.
I assumed that all 62 million registered vehicles in the U.S. got 35 miles to the gallon and were driven 25,000 miles a year. In fact, I suspect most cars are less fuel efficient and probably also driven further - 32% of all registered vehicles are commercial, as in 18 wheel rigs and tractors.
I assumed that a tree was a truncated cone.
I assumed that the volume of a tree was well approximated by the number of board feet of lumber it contained.
I've assumed that all of the carbon from gasoline is combusted and becomes carbon dioxide.
I've assumed that our engines burn 100% pure octane.
There may be other, unstated assumptions that I missed; feel free to point them out.
What percentage of America's surface would we need to plant with trees to match the carbon output from all the cars on the road in the States each year?
Every gallon of gasoline releases 186.37 moles of CO2, or about 2.236 kilograms, or about 5 pounds.
If you drive 25,000 miles per year in a car that gets 35 miles to the gallon, then that's 714 gallons of fuel per year, or about 1.786 tons of CO2. This is 0.487 tons of carbon.
A tree sequesters carbon for it's natural life; let's start there. It adds carbon as it grows. The rate at which it grows will determine how much carbon it absorbs.
A Massachussetts Woodland Steward article from the June/July edition in 1999 suggests that the volume of 14" diameter conifer trees should increase at roughly 5% per year.
Each tree will have a volume of roughly 0.25957 cubic meters (same article, based on the fact that it will have 110 board feet in it), a mass of 168.7 kilograms. The composition is approximately 60% water, 40% cellulose, or 67.48 kilograms of cellulose. Cellulose is 4/9ths carbon, so that's 30 kilos of carbon.
That tree is 60 years old, by the way.
So each year, a 60 year old conifer removes an additional 1.5 kilos of carbon from the environment. That means that, in order to support a car that gets 35 miles per gallon 25,000 miles, you'd need 294 conifers that were 60 years old.
There are approximately 62 million vehicles in the U.S., meaning that we'd need 18,228 million trees to support our car habit.
Trees of these type can be planted at 25 to the acre, which gives you 729 million acres of woodland, or about 3 million square kilometers, roughly twice the arable land area of the U.S.