"he has no children. all my pretty ones? did you say all? o hell-kite! all? what, all my pretty chickens and their dam at one fell swoop? "

Natural selection is the process by which nature selects organisms or species which fit closely to the environmental conditions. The question of how it can negatively affect humans is thus related to drastic changes in environmental conditions such as climate change. If climate changes become worse in the near future, the criteria for natural selection will also change. It has been argued a lot that changes in climate would not be in favor of currently living organisms, hence, nature will start eliminating humans along with other organisms.

Here is an example: if global warming results into increase in temperature, ice will melt and lead to sea level rise. Most of the continents will be covered with water. On the other hand, terrestrial animals including humans are not able to survive in the water which will result in their elimination.