I've somewhat recently been going down the climate change + excess CO2 rabbit hole. I'm trying to grasp it and am hoping that my not-quite napkin math can be doublechecked.
We've been thinking about moving closer to town, partly to drive less. I gather that the big issue with fossil fuels is that there's no sequestering in their lifecycle, at least in the present. So you burn them, but they don't get sequestered. So if we were burning wood, it should at least even out, possibly be negative depositing some carbon in the soil.
I started to wonder about the forest that we have, and that maybe maintaining this forest and keeping someone from logging it/developing it, is actually of some benefit. So I started to look into carbon sequestion figures for Idaho forests.
We have 11.5 acres of land. A lot of it is forest, but much of it isn't ideal or very dense. Maybe 7 acres equivalent? Maybe less? Let's be optimistic and say 7.
From what I've read, Idaho forests should be worth about 1.21 metric tons of CO2 equivalent per year. This, if accurate, has me at 8.47 metric tons per year in the negative. Which, it could easily be less.
Our daily driver, largely dictated by road quality, has been a 1991 Landcruiser. Estimating 85% highway driving, 15% city, and 15,000 miles per year, fueleconomy.gov puts me at 10.5 metric tons of CO2 per year! Now I usually get slightly better than the EPA estimate -- 14-15 MPG instead of 13MPG highway. But sometimes there's a trailer involved. At best, it's probably about 9 metric tons of CO2.
So now we are CO2 positive with just the daily driver! Comparable vehicles that we can realistically drive will be a lot better, but still close to 7 metric tons per year.
Estimating 250 gallons of propane use per year (hot water, dryer, and stove) puts me at 1.4 metric tons of CO2. I think we use a hair more, but this is close.
Now for grid power: I see about 5,500kW/hour used in the past 12 month cycle. Our power mix is 75% hydroelectric, 13% nuclear, and 12% "nonspecified" (whatever that means?) -- I guess this is lower CO2 than others.
From this website:
https://www.dw.com/en/fact-check-is-nuclear-energy-good-for-the-climate/a-59853315
I see different esimated figures. I figure they're worth taking with a grain of salt, but here it goes.
75% hydro should be 16.5kg CO2 at 4 grams per kw/hour.
13% nuclear should be 83kg CO2 at 117 grams per kw/hour.
12%, not sure what to call it, so going to leave it out.
This is about 0.1MT CO2 per year, so a lot less than vehicles or propane.
It seems like it would be more carbon friendly to use even basic, non-heat pump hot water heater than to use propane. Is that right? Given this power blend.
Back when we were using electric for hot water, dryer, and stove, we used about 16,000kW hours per year. So maybe 0.3-0.4MT CO2/year. Really seems like propane is less carbon friendly in this case.
Now for food!
If we eat 400lbs of beef per year, on average. Using the worst case 60kg CO2 / kg of beef, is that 10.9MT CO2? It can't be right, can it? More than the Landcruiser? Lamb would cut that in less than half.
Now the beef might not be that high in terms of CO2, but it's probably not less than half, right?
My estimates don't account for grass CO2, which seems like mostly a wash. Also doesn't account for CO2 emissions due to other purchases.
Does this math look plausible? Am I thinking correctly about this?
If so, the situation looks pretty dire!
Some links I have been using:
https://www.epa.gov/energy/greenhouse-gas-equivalencies-calculator-calculations-and-references
https://extension.psu.edu/the-economic-value-of-private-forests-and-climate-change-mitigation
Thank you!
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