The invisible threat

The world is getting hotter because __________ us!

Our factories and planes __________ the air dirty.

When __________ sun shines, everything gets hot.

And the dirt stops the hot air from going __________ to the sky.

Because the hot air has nowhere to go, __________ gets hotter.

Already our world is __________ than it was one hundred years ago.

Hot countries may become drier and the people who live there will not be able to grow food. Ice in cold areas __________ changing to water because of higher temperatures.

When this happens, the seas become bigger. Some towns __________ the sea may have a problem soon.

We can help __________ we stop making the air dirty but we must do something fast.