You just need the density of permafrost and then you can compute the volume from the exagram value, and depending on how thick you make it you get back either the surface of northern Canada and Siberia or you get a really really tall tower of permafrost that reaches into low earth orbit :-).
> I wonder how they have any confidence in the error range.
It is my understanding that there are many many core samples at various locations in the permafrost to understand its nature and make up. My guess would be that they derive the error ranges using the change in concentrations between all of the sample points leading them to a median and mean difference in concentration samples as their base set.
You just need the density of permafrost and then you can compute the volume from the exagram value, and depending on how thick you make it you get back either the surface of northern Canada and Siberia or you get a really really tall tower of permafrost that reaches into low earth orbit :-).
> I wonder how they have any confidence in the error range.
It is my understanding that there are many many core samples at various locations in the permafrost to understand its nature and make up. My guess would be that they derive the error ranges using the change in concentrations between all of the sample points leading them to a median and mean difference in concentration samples as their base set.