The event/issue is  climate change.

There are no real people in this cartoon.

The people in the first box represent people who say they care about the environment. The people in the last box represent people who truly care about the environment.  

The cartoonist's opinion is that a lot of people say that they care about the environment, but very few actually do care.

I agree with the cartoonist, because many people say things that we cold try to help the environment, but they never actually do anything to help the environment.