A country with trains might have the equivalent of 3-10 times the length of the country worth of train tracks, and countries are roughly 600-3000 miles across, with perhaps 10-100 countries with a lot of trains that are also not far below the 600 mile size. The geometric means are approximately 5.5vlength , 1350 miles, 30 countries. Multiply all of these and you get 222,750 miles.
Q1 Answer: 222,750 miles.
Post-hoc edit: If you take these numbers and do the right math on them, you get a more accurate answer. The right math for this kind of thing is not just to multiply the geometric means. You want to take 50 draws from a random variable that’s the product of size S times length multiplier L, which are lognormally distributed. If you do that you get about 600,000. If you do it for 30, you get 346,000. So, if you use the numbers I gave with some actual math, it’s 346,000. But I looked at the correct answer before deciding to bother to do the math.
Air freight is perhaps 10%-30% of passenger travel since I see more passenger planes at airports than freight. Passenger travel is easier to estimate. Say that each of 1,000,000,000 people travel twice per year by air. 15 people plus their baggage is one metric ton. 2 × 17% × 1,000,000,000 / 15 = 22,000,000 metric tons.
Q2 Answer: 22,000,000 metric tons per year for both years.
A country with trains might have the equivalent of 3-10 times the length of the country worth of train tracks, and countries are roughly 600-3000 miles across, with perhaps 10-100 countries with a lot of trains that are also not far below the 600 mile size. The geometric means are approximately 5.5vlength , 1350 miles, 30 countries. Multiply all of these and you get 222,750 miles.
Q1 Answer: 222,750 miles.
Post-hoc edit: If you take these numbers and do the right math on them, you get a more accurate answer. The right math for this kind of thing is not just to multiply the geometric means. You want to take 50 draws from a random variable that’s the product of size S times length multiplier L, which are lognormally distributed. If you do that you get about 600,000. If you do it for 30, you get 346,000. So, if you use the numbers I gave with some actual math, it’s 346,000. But I looked at the correct answer before deciding to bother to do the math.
Air freight is perhaps 10%-30% of passenger travel since I see more passenger planes at airports than freight. Passenger travel is easier to estimate. Say that each of 1,000,000,000 people travel twice per year by air. 15 people plus their baggage is one metric ton. 2 × 17% × 1,000,000,000 / 15 = 22,000,000 metric tons.
Q2 Answer: 22,000,000 metric tons per year for both years.