The End of All Mankind? While probably not for a very long time to come, the existence of humanity is bound to eventually vanish from our planet. By ways unknown, little is certain about the nature or time of our demise, even from the most renown of scholars. Below are the list of the 5 most probable and likely ways man will meet its doom.
One of the most dangerous threats to the human population is a simple virus — that is, a deadly disease that spreads rapidly throughout the world. Within the last century we’ve had four major flu epidemics, as well as HIV and SARS, and scientists says it’s inevitable that another will occur. The 1918 influenza outbreak killed more people than World War I, and if a deadly contagion surfaced today, it could spread even faster and infect even more people. Considering how quickly diseases spread though all forms of modern transportation — and the amount of international travel that takes place today — an outbreak similar to that of 1918 “could have a more devastating impact,” says Maria Zambon, head of the Health Protection Agency's Influenza Laboratory.
And if nature doesn’t send such a deadly contagion our way, mankind just might. Biological warfare is another threat that looms over the modern world, and diseases like Anthrax, Ebola and Cholera have all been weaponized
2. Global Warming
Whether you believe in man-made warming or not, there’s no denying the planet is getting hotter. In fact, 2010 tied 2005 for the warmest year on record with global temperatures 1.12 degrees Fahrenheit above the 20th century average. And there are some who say that we’re running out of time to stop irreversible climate change — in fact, by some calculations we’re less than a decade away.
According to climate scientists, once a critical greenhouse gas concentration threshold is passed, global warming will continue even if we stop releasing gases into the atmosphere. If this occurs, the Earth’s climate will become more volatile, resulting in catastrophic weather patterns. Plus, as temperatures rise, food will become scarce, air quality will worsen and diseases will spread. The World Health Organization estimates that 150,000 people are already killed by climate change-related issues each year, and U.N. Secretary General Ban Ki-moon has said that global warming poses as much of a threat to the world as war.
3. Nuclear Warfare
The Cold War is over, but the threat of nuclear war still exists today, with a number of countries possessing the capability of deploying such destructive devices. In addition to threats from the explosion and radiation, there are also indirect effects such as contaminated food and water supplies, poor air quality, destruction of power grids affecting communication and transportation, and nuclear winter.
It’s been theorized that detonating nuclear weapons will cause large amounts of smoke, soot and debris to enter Earth’s stratosphere, reducing sunlight for months or even years. Such a nuclear winter would result in severe cold temperatures and interference in food production. In 2007, scientists Brian Toon and Alan Robock concluded that if India and Pakistan were to launch 50 nuclear weapons at each other, the entire planet could experience 10 years of smoke clouds and a three-year temperature drop.
Movies like “Deep Impact” and “Armageddon” may be works of fiction, but the threat of an asteroid hitting the planet is quite real. After all, the Earth and moon have craters that prove they have a long history of being hit by large objects from space.
In 2028, the asteroid 1997XF11 will come close to hitting Earth, but scientists say that won't actually happen. However, if it were to hit the planet, the mile-wide rock would race toward the surface at roughly 30,000 mph and probably wipe out most life on the planet. The species that did survive would be in for a rough life after such a catastrophic event. Dust from the impact and ash from the forest fires would remain in the Earth’s atmosphere for years, blocking sunlight and destroying plant life, which would cause food shortages worldwide. However, NASA's Spaceguard Survey searched for large near-Earth asteroids and has determined that there are no threatening asteroids as large as the one that killed the dinosaurs 65 million years ago.
5. Gamma Ray Bursts
When a supernova explodes, it unleashes a massive gamma ray, or high-frequency electromagnetic radiation. Most of these huge bursts of energy take place too far away to harm Earth, but if one occurred within 30 lightyears from the sun — which is pretty close on the cosmic scale — it would be disastrous. The gamma ray would blow apart a portion of the planet’s atmosphere, produce worldwide fires and kill most of Earth’s species in just a matter of months.
However, the odds of a gamma ray burst destroying the planet are extremely low because not only would the supernova need to be close to Earth, the explosion would also have to be pointed in Earth’s direction. Fortunately, there are few high-mass stars with the potential to explode.