If humans continue to disregard Mother Nature and keep on using up the Earth's resources unfairly or excessively (e.g. not recycling whenever possible) or continue polluting water bodies or the air, then sooner or later, we will surely bring about the world's doom. We have already created a hole in the ozone layer and have not tried our best to stop - how long will it be before something else major happens? Will we only start to change then?
From my point of view, we should reuse, reduce and recycle more often to ensure the survival of not only the human race, but the survival of other species of animals and plants as well. We can conserve resources more often as well.