Individually, they are the size of a grain of rice. Together, and under the right conditions, the only thing that has stopped them is their own insatiable hunger. Behold the devastation of the Mountain Pine Beetle:

It’s surreal to walk around in the forests with so many dead trees. They creak in a Halloween-y kind of way. Up close, the trees look like they were infected with an STD. From afar, the deep greens you expect to see rolling across the mountains are instead streaked with huge patches of grey.

The rangers remove the ones that pose the greatest threats to life and property, but there’s really nothing they can do about millions of dead trees except wait for them to fall down and hope there’s not a fire.

How the hell does this happen? It starts like this: one beetle, a female, will land on an old or weakened tree and release her tantalizing pheromones. Others come. A lot of others. Males and females. They all do their sexy dance together and then burrow into the tree to lay their eggs under the bark.

The tree has defenses – if it’s young and has access to plenty of water the tree can fight off the attack by covering the beetles in sap. But the beetles have countermeasures. There’s a fungus they carry with them, and when they burrow into the tree the fungus will prevent it from being able to produce the sap. It also cuts off the flow of water and nutrients. So while the larvae are eating the soft, inner bark, the tree can’t eat or defend itself, and it dies.

Normally, this is part of the cirrrcle of liiife. The beetles get a breeding ground and in taking down the old and weakened trees there is plenty of room for new growth. The beetles’ numbers are held in check by hard winters (the severe cold kills most of the eggs and larvae) and wet summers (trees that have access to lots of water can typically fend off the attacks by producing more sap).

But these last few years have been different. Unusually hot, dry summers and mild winters, along with the fact that the forests were filled with old growth trees, have made for very favorable conditions for the pine beetles. The good news? The pine beetles are gone now. They ate their way through everything they could and died out themselves.

Climate change is really happening, and its effects are devastating.

There was a display at a visitor’s center in the Petrified Forest that I thought did a great job of describing the difference between weather and climate:

Weather is the local conditions over just a few days. Climate is the product of several interrelated systems over the course of thirty years or more: the atmosphere (air), lithosphere (earth), hydrosphere (water), cryosphere (ice), and biosphere (life).

You can observe the climate of your own region by walking out your door. Is the air clean or is there smog? Is the land you live on at sea level or a higher elevation? How much rain fall do you typically get? Are you land locked or are you near an ocean or a lake? Do you get snow in the winter? What kinds of animals and plants are thriving?

If any one of these things were to change it would impact all the others.

I know all your career coaches have been telling you to focus on the big things, but we really should be sweating the small stuff. These small changes are making a big impact. Here are 25 things you can do to help.