Why can't farmers in very parts of the word grow enough to eat? What do you think we should to do save the earth?

we are destroying the Earth . The seas and rivers are too dirty to swim in . There is too smoke in the air in many cities in the world , we are cutting down too many trees . We are burning the forests . We are also destroying a lot of plants and animals . Many areas of Earth are wasteland . Farmers in many parts of the world can not have enough to eat . In some countries there is too little rice . The Earth is in danger . Save the Earth

why can't farmers in very parts of the word grow enough to eat ?

what do you think we should to do save the earth ?