100 times. I read on the internet awhile back that 1 or 2 would destroy the entire planet.
How much more powerful are the present day nuclear bombs than the ones dropped on Nagasaki and Hiroshima?
From Quora :
The bombs dropped on Hiroshima and Nagasaki were relatively low yield weapons with yields of 15kt and 21kt of TNT respectively. The average nuclear warhead today has a yield of about 200kt and the most powerful nuclear device ever detonated had a yield of 50mt with a maximum of 100mt. The reason we stopped producing bombs with the explosive power of millions of tons of TNT is because we are able to accurately place the warhead within a few feet of the target.