I tried their calculator with 18 tons (36,000 pounds). It said ~1050 trees @ $0.10 per tree, so $105 total per year. vs $45 or whatever on Terrapass.
Let’s shoot for an order of magnitude difference. How might we sell it for $4.50 a year?
Let’s shoot for an order of magnitude difference. How might we sell it for $4.50 a year?
If you plant 1050 trees at $105 per year (I rounded to $110), the will extract 18 tons of CO2 from the atmosphere per year. This assumes that you need to just make a one-time payment and as long as those 1050 trees are alive and healthy, they'll keep extracting 18 tons of carbon from the atmosphere every year.
Since we can't assume those trees will keep on living and being healthy as long as you're alive, we need an average healthy lifespan for them. Instead of trying to figure that out (googling resulted in wildly different answers), I decided to assume their healthy lifespan is 10 years. That seems very conservative, but it does give us round numbers to make the math convenient.
So every 10 years, you would need to pay $110 to keep offsetting your carbon. That comes out to $11 per year.