Martel (1997) estimates a considerably higher annualized death rate of 3,500 from meteorite impacts alone (she doesn’t consider continental drift or gamma-ray bursts), but the internal logic of safety engineering demands we seek a lower bound, one that we must put up with no matter what strides we make in redistribution of food, global peace, or healthcare.

Is this correct? I'd expect that this lower-bound was superior to the above (10 deaths / year) for the purpose of calculating our present safety factor... unless we're currently able to destroy earth-threatening meteorites and no one told me.