On Meteors and Megatons
I have two major objections to this form of analysis, where nuclear weapons are used as some kind of barometer for general energy release. The first is about the character of energy release is important — because it affects how these things are felt at the human scale. The second is about whether these sorts of comparisons are actually clarifying to the general public.
I think the objection is ironic, because no protest against measuring nuclear explosions in kilo- or Megatons of TNT is made, although it’s a similar same issue — does detonating 50 kT of TNT give the same result as a nuclear blast with the same yield? Another thing making it a poor argument is that not all nuclear blasts are the same — ground vs airburst, for example. If we are to compare on effect, then you create the bizarre scenario in which a two detonations of the same energy release aren’t classified the same. This isn’t meant to be a precise equivalence.
We can compare earthquakes, at least in energy release, and do so because they are relatively common. Even still, we can’t equate the devastation because it depends on the quality of construction in the affected region. A 7.0 earthquake in Haiti caused of order a quarter-million deaths, while other quakes of similar strength cause few, or none. Meteor impacts, though? We don’t have a common ground for comparison.
As for the suggestion of describing the event in terms of actual damage, sure. I think journalists already tend to do this, though.