The Russians are building new nuclear-armed missiles, bombers and submarines to replace those built in the 1980s and now reaching the end of their operational lives. Their nuclear torpedo, more of an underwater drone, deliberately seeks to turn a city into a radioactive wasteland that would last for decades. It is a throwback to the worse designs of the Cold War, long since abandoned. And the U.S. is rearming as well. The Obama administration is planning to spend over $1 trillion in the next 30 years on an entire new generation of nuclear bombs, bombers, missiles and submarines to replace those built during the Reagan years.
Because of decisions likely to be taken this year and next, nuclear weapons will become a normalized and permanent part of the 21st-century American arsenal, and therefore of the arsenals of many other nations; nuclear weapons, that is, will have become an essential element of the human future -- as long as that future lasts.
In 2014 there are more nuclear weapons than ever, but we don't really talk about them very much. Instead we talk, primarily about the possibility of human extinction due to climate change, food shortages, ocean acidification or, occasionally, super-volcanos or comet collisions. All of these things are possible, and all of them are very unlikely to cause the extinction of humanity.