There are a few science fiction films which have spawned the film industry, about the destruction of Earth. Formerly responsible were dangerous enemy aliens, fantastic creatures, sometimes meteorites and asteroids and other are pandemics and deadly viruses. While all of these scenarios are based on the inexhaustible imagination of some talented screenwriters and directors, there are some scientists who express there real concerns for the future of our planet.
Global Warming
Climate change is the greatest threat which confronts the planet, as many scientists agree. Because of this extreme weather conditions seen in many parts of the world may become even more extreme, such as more drought in some areas, floods, rising sea levels, etc.
Nuclear war
Many scientists still fear that the end of the earth will come from a nuclear war, if nuclear weapons that many countries own, fall into the wrong hands.
Asteroid
There are some scientists who fear that what has been done in Hollywood scenarios can actually happen in reality. An asteroid wiping out the entire Earth. Besides, as some experts suggest, dinosaurs became extinct when an asteroid collided with Earth. In 1908 in the Tunguska region of Siberia a meteor destroyed an area of approximately 2,000 square kilometers.
Pandemic threat
New pathogens are appearing every year. Recently we had the cases of SARS, severe acute respiratory syndrome, avian influenza and coronavirus MERS in Saudi Arabia. A deadly disease could be transmitted as lightning in our interconnected world. The threat of a global pandemic is very real, as argued in their book Biology, writers Joseph Miller and Ken Miller.