Some people consider global warming to be the most devastating environmental problem which we have at the moment, others have believe that the deforestation more severely affects our world, and these both sides will remain the centre of discussion.
One school of thoughts, presume that global warming has a destructive role regarding environment, because it brings about various catastrophic events; like, floods, wildfire etc. Firstly, due to global warming, there is an up-surge in the temperature of the earth that causes the glaciers and polar ice to melt and it results in soaring the water level in oceans and ultimately, inducing the flood which affects wider populations. Moreover, the global warming also has a pessimistic role in producing wildfire; due to high temperature, the forest fire occurs, which dramatically causes death and destruction of wildlife and thus damaging the major portion of the environment.
On the other hand, other school of thoughts, think that the deforestation has more detrimental impact on the environment; for example it disturbs bio-diversity, water cycle etc. As forests are home to wild animals, one cannot negate their importance, once there is declination in their number, the proportion of animals residing there also decreases due to their death because of either shortage of food or loss of habitat. Furthermore, deforestation also disturbs the water cycle because of no or less transpiration or evaporation from leaves, and thus affecting the patterns of rain, making the land infertile and finally, leading to the droughts.
Conclusively, I believe that the detrimental impacts of both the global warming and deforestation cannot be defied as they influence the environment badly by bringing out floods, forest fire and affecting bio-diversity and water cycle, respectively, and none of them surpasses other for such damages.