To speak about environmental problems, you need the appropriate vocabulary.
Extinction of animals - when types of animal no longer exist;
Soil erosion - destruction of the top layer of earth that plants grow in;
Ozone depletion - reduction of the amount of ozone;
Loss of biodiversity - when we do not have enough types of plants and animals that exist in a particular area or in the world generally, or the problem of protecting this;
Depletion of natural resources - reduction of natural resources;
Global warming - when the air around the world becomes warmer because of pollution;
Greenhouse effect - the gradual warming of the Earth's surface caused by an increase in pollution and gases in the air;
Radioactive contamination - pollution containing harmful radiation.
Examples:
We are afraid of radioactive contamination.
People try to do something to avoid ozone depletion.
Have you ever heard about loss of biodiversity?