Danger #3: Global Warming
Unlike the two previous threats to humanity, global warming is not exaggerated at all. It is a serious threat to the Earth and its consequences can be fatal to the human race. Global warming, not only endangers the Earth and nature, but also humanity. It is also the immediate cause of the abnormal recurrence of some other natural catastrophes such as hurricanes and tornadoes.
Melting North Pole ice. Source: Christopher Michel, via CC by 2.0.
Pine beetle damage to the forest.
Drought on agricultural lands by global warming.
Flooding in Bangladesh.
Global warming also endangers some species to near exctinction.
If we could move a part of the human population to space, the pollution and greenhouse gas emission would decrease and thus the global warming problem would be resolved. This is why space colonization is so important to our home planet.