Climate Change Bringing End of the World? How Much Should I Care?

I read Johann Hari's review of the book Storms of my Grandchildren, by James Hansen, in Slate magazine this morning. http://www.slate.com/id/2242201/ Hansen is a NASA scientist who has been correctly predicting climate change since 1981, and his current prediction is that if we don't make enormous global changes in behavior, we will soon reach a tipping point where we will no longer be able to prevent climate changes, rising sea levels, etc. He advocates Gandhi-like civil disobedience in support of environmental protections.

This article stuck with me today, leaving me miserable and depressed. I have been contemplating whether I have a responsibility to join Hansen in civil disobedience, or whether Hansen is wasting his time because there is just no way people are going to make the sacrifices that would be necessary to have any effect. I have been looking out the windows and imagining the streets empty, the buildings crumbling, my city and the entire earth abandoned.

I know, it's quite dramatic, but I feel some variation of this once every couple of months, after I watch or read something that hits a certain nerve. My boyfriend refuses to let me watch the History / Discovery channel "end of the world" programs anymore, because I might be depressed for days. Being depressed and obsessing about end of the world scenarios is not very productive, but is it unnatural?

Shouldn't we be depressed and obsessive about this?

I really find it more interesting that I am able to forget about it and go on with my life after a day or two. If I refuse to think about it long enough, some subconscious process of denial takes over, and I am able be happy and focus on other things. Often, I will flip right past the magazine article about climate change. "I know," I might think to myself, "it's over for us. Sorry grandkids!"

I think there is some subconscious defense mechanism that will not allow me to truly contemplate the enormity of this problem most of the time. And I think the same thing is happening to most of the people out there. I know that there are a lot of people out there who don't believe in climate change, and I won't even attempt to guess what is going on in their heads. But the rest of us, who acknowledge the reality of the problem, and express concern, but then we have to decide what to make for dinner, and find a babysitter, and meet a deadline, and suddenly the extinction of the human race is barely an afterthought. I don't get it.

What allows us to know that something is real and yet not feel as if it is real? What do we do about it?