Danger

As a species, we tend to react to threats that are direct and personal, and conversely tend to ignore threats that the non-specific and impersonal.  We also tend to react to dangers that are proximal and imminent (the tree falling in the forest), and to behaviors we personally find disgusting.  

I think it's interesting and says something about our species that two of the top three threats we've evolved to avoid are from other humans (direct and personal attacks and disgusting behaviors), and only one is from the natural world (proximal and imminent dangers - the disaster scenario).  We're obviously our own worse enemies.

We react to dangers that are proximal and imminent, but we're not responsive to threats that are distant and gradual.  This may be why people don't get as alarmed about climate change compared to the actual threat that it does pose - sure, it'll be catastrophic for us as a species, eventually, but not necessarily this year.  So we ignore it, or delegate action on it to such a low priority compared to perceived proximal and imminent threats that we do nothing about it.

In addition to climate change, we are threatened by the eventual Cascadia subduction zone earthquake, which has the potential to take out much of the northwest United States and southwest Canada, and the Yellowstone supervolcano, which could cover over half the U.S. in volcanic ash. But who knows when these disasters will happen, so we focus our attention on this week's weather forecast even while we continue to build new infrastructure over the geological failures of our continent.

I'm not saying we should live in a perpetual state of anxiety about these eventual disasters, but am merely pointing out the ways that our minds work.