The earth has a radius of 6400 km. Surface area is 4πr² and about 1⁄3 of that is land, giving around 200 million square kilometers of land surface.
I think… most of that is barely populated, and probably has few train tracks? Let’s say 1% of it is densely popualated, 10% is sparsely populated, and 90% is basically unpopulated. In the densely populated bit, I could believe 1 km track per square km area. In the sparsely populated let’s say a tenth of that, and ignore the rest. That gives… 2 million km in dense, plus another 2 million in sparse for 4 million km in total.
That feels low, I think? But I’ll stick with it unless I come up with something better.
I think a lot more freight goes by boat then plane. Let’s say plane is 1% of boat.
I think an aircraft carrier displaces, what, 100,000 metric tons? So it’s maybe reasonable to guess that a respectable bulk transport can carry 100,000 metric tons of cargo.
Let’s say at any given time there are 100 of those underway, on journeys lasting 30 days. That makes about 100,000,000 metric tons shipped annually by boat, and 1,000,000 by plane.
Between 2009 and 2019 I’m gonna guess it went up by enough to count as one order of magnitude. So let’s split the difference and call it 300,000 in 2009 and 3,000,000 in 2019.
Suppose air freight has dectupled every decade, starting at one metric ton in 1909. Then we get 10^10 metric tons in 2009 and 10^11 in 2019. That’s 4½ orders of magnitude more than my other answer. :/
I currently suspect this one is too high and that one is too low, but that one is closer.
Attempt at q1:
The earth has a radius of 6400 km. Surface area is 4πr² and about 1⁄3 of that is land, giving around 200 million square kilometers of land surface.
I think… most of that is barely populated, and probably has few train tracks? Let’s say 1% of it is densely popualated, 10% is sparsely populated, and 90% is basically unpopulated. In the densely populated bit, I could believe 1 km track per square km area. In the sparsely populated let’s say a tenth of that, and ignore the rest. That gives… 2 million km in dense, plus another 2 million in sparse for 4 million km in total.
That feels low, I think? But I’ll stick with it unless I come up with something better.
q2:
I think a lot more freight goes by boat then plane. Let’s say plane is 1% of boat.
I think an aircraft carrier displaces, what, 100,000 metric tons? So it’s maybe reasonable to guess that a respectable bulk transport can carry 100,000 metric tons of cargo.
Let’s say at any given time there are 100 of those underway, on journeys lasting 30 days. That makes about 100,000,000 metric tons shipped annually by boat, and 1,000,000 by plane.
Between 2009 and 2019 I’m gonna guess it went up by enough to count as one order of magnitude. So let’s split the difference and call it 300,000 in 2009 and 3,000,000 in 2019.
Another attempt at q2:
Suppose air freight has dectupled every decade, starting at one metric ton in 1909. Then we get 10^10 metric tons in 2009 and 10^11 in 2019. That’s 4½ orders of magnitude more than my other answer. :/
I currently suspect this one is too high and that one is too low, but that one is closer.