had we been paying attention.

On a sunny day, it is hotter to stand out in the sun than it is to stand in the shade.
Trees provide both shade and lower the temperature by releasing moisture out through their leaves. This could be considered a form of natural air-conditioning.
When you cut down a large tree, that spot gets hotter on a sunny day. If you cut down a lot of trees that grow near each other, that area becomes drier and hotter.
When whole forests are cut down, local rain patterns change. Rainfall diminishes in areas that were once dense forests after they are cut down.
When trees that line a small year round creek or stream are cut down, that water usually ceases to flow during dry spells.
When human activity destroys vast areas of once forested areas, noticeable climate changes take place.
Humans have the ability to alter climate conditions, for the better or worse, through their activities.
Be part of the solution-plant a tree or two, or many.