Scientists estimate that there have been at least 5 mass extinctions in the last 540 million years.
They also believe that we have entered a new extinction event.
Species are becoming extinct at a much faster rate than before.
Instead of asteroids or volcanic eruptions, the current event is the result of human activities.
Human activities, for example, have led to global warming.
Global warming is the result of an increase in carbon gases in our atmosphere.
These gases trap heat from the sun, so the Earth is getting warmer.
As a result, sea levels are rising and weather patterns are changing.
In addition, we humans are destroying the habitats of many plants and animals.
Cutting down forests and polluting rivers destroys the habitats of many forms of life.
There is no longer any doubt that this is happening
Species of life are disappearing at an increasing rate.
Global temperatures are rising and weather patterns are changing.
Scientists are warning us that fast action is necessary to save our future.
If we don't act, we may go the way of the dinosaurs.
(This new extinction event is caused by humans.)