People worry about nuclear weapons and nuclear holocaust. I don't think that's the real problem

Why?

Because nuclear holocaust is theoretical not actual. We have made it around 80 years now since Hiroshima and Nagasaki. Because of this maybe we have figured out how to survive nuclear weapons.

However, Global Climate changes are eventually going to kill everyone on earth. I think people are afraid to say this but it is true. As you are beginning to see in places like the U.S. people who are dying in their home countries in Central and South America are coming to the U.S. so they don't die in their native lands.

The same thing is happening in Africa and the Middle East as people migrate north to Europe and Russia and even China so they can better survive here on earth.

It's important for people to realize that this is only going to get much worse.

However, if you don't deal with the Cause which is Global Climate change you are losing the whole point here. 

Global Climate Changes are going to be worse than Nuclear weapons have ever been because it isn't people directly that is the problem but what all people have done the last 25,000 years to survive and that's all catching up with us now and is going to lead to human extinction unless solutions are found soon. (within a few hundred years).

So, which is worse: Nuclear Weapons or Global Climate changes? 

I would say Global Climate changes are much worse in the long run. Because Global Climate changes can and will lead to human extinction unless they are dealt with usefully and effectively somehow.