The biggest issue in recent years that leads to talk about a possible future inhabitability of the globe is a term that’s been thrown out a lot: global warming. Before talking about how humankind is involved, it is important to note that there also exists a natural climate change. It has gone from freezing temperatures with periods where the oceans were completely iced over, to blisteringly hot temperatures. This natural variability takes quite a while to go from one extreme to the other. It is also predictable to some extent (due to Milankovitch cycles, which use the tilt, precession, and eccentricity of the Earth to detect climate change patterns), and so should not provide much of a problem for humankind.
Additionally, natural climate change only accounts for a slight variation in temperature over the years. This indicates that although global warming consists of both natural and anthropogenic parts, the anthropogenic part may be the one causing the majority of the damage. Human invention and technology (specifically those that use or rely on coal, oil, and other “dirty” energy sources) warm the Earth by releasing greenhouse gases that bring in increasing quantities of harmful UV radiation. As long as people continue to rely on modern day technology, such as petroleum-based transportation and electricity consuming appliances, the anthropogenic portion of global warming will continue to persist. This one problem alone can lead to numerous ways in which humans could meet their end, including but not limited to: floods caused by rising sea levels due to melted polar ice caps, normally occurring weather-related disasters, and stresses to other forms of life, thereby destroying the tightly packed network of the global food chain.
|A polar bear on top of melting ice,|
an effect of global warming.
Another major issue that could lead to human extinction is a possible collision by a meteorite. In
the past, dinosaurs were thought to have been destroyed by a giant asteroid. If even the giant fearsome dinosaurs were killed by an asteroid, how would frail, puny humans (in comparison to the giant dinosaurs) fare? It doesn’t take an expert to realize that an asteroid of decent size could cause major damage to human life. Although large meteorite collisions are rare, just one could wipe out all of humankind. To give an idea of how rare large meteor collisions are, a 1 km meteorite that could cause a nominal global effect (about 1 million fatalities) is expected to occur once every million years, and a 10 km extinction class event is only expected to occur every 100 million years. Despite the low probability of events, if a meteorite did threaten to hit, humankind would either need a way to repel it or an escape route to ensure survival. Ways to deal with incoming meteors are currently in the works, but as of yet, there is not confirmed deterrent method. Meteors are just one facet of all the cosmic threats humankind faces, many of which could happen in the near future.
|An artist rendition of meteorite impact|
destroying the dinosaurs.
Because of these impending threats to planet Earth, it is essential that the human race move outwards, and find new places to live across the universe. There are many risks associated with space travel, such as poisonous radiation, and we should start finding ways to prevent or at least reduce these problems today. That way, if the time ever comes that we need to leave planet Earth to ensure our survival, we will be ready. Lastly, you may note that I did not include the risks of artificial intelligence and manmade nuclear weaponry that could obliterate the population. This is due to the fact that these threats will exist no matter where humans live, and so there is not much of a way to account for these (other than separating the human race into multiple planetary environments). We should rather spend our time preparing for threats that matter on our current planet, where all of humankind currently resides.