That depends on what you mean by "destroy the world". If you mean completely annihilate the world so that all that is left is an expanding cloud of dust, then the answer is probably that it would take thousand to millions of times more bombs than currently exist of much greater yield that any that have ever been built. In order to completely destroy Earth, you would need a weapon capable of actually throwing the materials that make it up outward with sufficient force to reach escape velocity. Hydrogen bombs are incapable of this. The atmosphere would slow the debris from such an explosion too much for it to escape. Additionally, there would not be enough hydrogen in all of the water on Earth to build enough bombs to accomplish the complete destruction of Earth. Now, if you mean how many H-bombs it would take to destroy all life on Earth, I don't know what the numbers would be, but it would still take more than are present in all of the arsenals of the world. In order to insure that you destroyed all life you would have to pretty much cauterize the the entire surface. This would require boiling away all of the oceans and melting the polar ice caps to insure that you got all life forms. While this is more doable than the complete destruction of Earth, it is still well beyond our capabilities. Finally, if you mean how many H-bombs would it take to make this planet uninhabitable by human, then you are getting into a scenario that is much more realistic, though I still question whether we even have the capability to do that.

Far more than any of us could possibly imagine. In spite of doom and gloom fantasies, humans lack the ability to destroy the world. We also lack the ability to destroy all life on it. However, we do not lack the ability to do substantial damage to the flora and fauna sharing this planet with us. But life has always pulled through and has gone on to diversify beyond our wildest dreams. It has been opined that god has an inordinate fondness for beetles - some 350,000 known species - so, perhaps, the next period might be that of the beetle. There have been three major and several minor decimations of species over the history of this planet that have identified with some confidence. These have occurred over relatively short periods of time geologically, but a very long period of time in terms of human life. The most recent, at the end of the Cretaceous period (~65 million years ago), changed the ecological balance on the earth by removing the dinosaurs as the dominant species. The largest occurred at the end of the Permian period (~225 million years ago), when some 96% of known species became extinct. The first major decimation happened during the Cambrian period (~550 million years ago). This oldest decimation has, in turn, provided us with tremendous knowledge about the evolution of life on earth. Mankind could trigger a mass extinction, but it would be far less devastating that those in the past.

It depends on how you classify 'destroyed', physically, we cannot destroy the planet, but we can DEFINATELY make it completely impossible to survive on, the radiation, dust clouds, and explosions themselves would easily annihilate almost every form of life on earth... But yeah, we cant like... blow chunks off the planet into space like in cartoons ;) Not yet at least : /

It would take about 7.. 1 for each continent..

According to my studies at the University of Nuclear Fusion Scientific Exploration, the world will blow up if one nuclear bomb were to be placed at the precisely California, then it would start a massive chain reaction that would trigger all of the other nuclear bombs in California, that would create a shock hundreds of thousands of miles across the world.This would cause all of the other bombs in the world to trigger, and melting all of the polar ice caps. Life that is not destroyed by the blasts, will certainly drowned!!!

We could make the world uninhabitable for humans with as few as 100 5 meg ground bursts. +5