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Nuclear weapons -

Everyone knows that nuclear weapons have the potential to cause instant devastation–a single explosion can leave thousands of people dead. But nuclear warfare can also have long-term consequences.

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Nuclear weapons -

According to experts Kennette Benedict and Nobuyasu Abe, nuclear explosions could trigger a “nuclear winter,” during which dust and sulfates prevent sunlight from reaching Earth.

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Nuclear weapons -

It would be very difficult to grow food during a nuclear winter, and there could be widespread famine for years on end. This could have disastrous consequences for mankind.

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Biological and chemical weapons -

Biological and chemical weapons may sound less scary than their nuclear weapon cousins, but in fact their accessibility means they pose an equal, if not greater, threat.

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Biological and chemical weapons -

While nuclear weapons are expensive and difficult to make, both biological and chemical weapons can be made on a budget. According to expert Angela Kane, both have the potential to cause a global catastrophe.

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Biological and chemical weapons -

These weapons are all the more worrying for the fact that some countries don't care that they’re banned. Biological and chemical weapons are both illegal, but have been used at least four times in the last 40 years.

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Climate change -

Perhaps the most obvious threat to be included on this list is climate change. Experts believe that by 2100 there is a 90% chance the planet will be 2°C (about 36°F) warmer, and a 33% chance it will be 3°C (around 37°F) warmer.

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Climate change -

If nothing is done to combat climate change and the planet does in fact warm by 3°C (37°F) by 2100, most of Florida and Bangladesh will be underwater and other major cities will be swamped.

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Climate change -

Of course, some action has already been taken to slow down global warming, but a lot more effort is required if we are to stop global temperatures from rising to these levels.

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Collapse of the global ecosystem -

We need our global ecosystem for things such as air, water, food, and shelter. And yet since the 1950s, activity such as deforestation has been rendering the ecosystem increasingly less inhabitable.

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Collapse of the global ecosystem -

An international group of scholars has determined nine “planetary boundaries” that allow the world’s ecosystem to stay stable, and humans have already surpassed the limit of four of those boundaries.

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Collapse of the global ecosystem -

According to Maria Ivanova, a professor of global governance at the University of Massachusetts, Boston, and Philip Osano, a research fellow at the Stockholm Environment Institute, the world’s ecosystems are at great risk.

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Antibiotic-resistant bacteria -

The antibiotics that we currently rely on to fight off many different types of bacterial infection are becoming less and less useful as certain strains of bacteria become resistant to them.

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Antibiotic-resistant bacteria -

This is a very real threat, as has been noted by David Heymann, head of Chatham House’s Center on Global Health Security.

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Antibiotic-resistant bacteria -

If scientists are not able to develop new antibiotics, the number of people killed each year by antibiotic-resistant bacteria could reach 10 million by 2050.

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Global pandemics -

In October 2018, Business Insider published an article that listed widespread outbreak of disease as one of the greatest threats facing mankind in the long-term future.

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Global pandemics -

The outbreak of the COVID-19 global pandemic in early 2020 serves as evidence that this threat was a lot closer than previously thought.

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Global pandemics -

Although the COVID-19 outbreak does not compare with the epidemics of days gone by (the plague wiped out 15% of the world’s population on two occasions), dense urbanization means that there could be more severe outbreaks in years to come.

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Asteroids -

Although asteroids may sound like the stuff of science fiction, they are in fact a very real threat. When an asteroid hit Mexico 65 million years ago, it wiped dinosaurs off the face of the Earth.

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Asteroids -

According to Tim Spahr, the CEO of NEO Sciences, an asteroid large enough to trigger a global catastrophe is likely to strike the Earth once every 120,000 years.

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Asteroids -

Also according to Spahr, an asteroid big enough could cause the Earth to cool by releasing particles that block the sun’s light. There could be famines that kill off hundreds of millions of people.

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Supervolcanic eruptions -

When the Toba supervolcano erupted in Indonesia around 74,000 years ago, humans were nearly made extinct by the billions of tonnes of dust and sulfate released into the atmosphere.

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Supervolcanic eruptions -

While it is impossible for scientists to predict a supervolcanic eruption more than a few weeks or months in advance, data suggests they happen every 17,000 years.

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Supervolcanic eruptions -

It has been 26,500 years since the last eruption, and we are therefore overdue. Although it may not extinguish the human race, a supervolcanic eruption would kill many and destroy agriculture.

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Artificial intelligence -

Many scientists are in agreement that AI to rival the human brain could be upon us in the next few decades and it is possible that machines more intelligent than humans will follow.

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Artificial intelligence -

This poses a threat to humanity because, according to five members of the Future of Life Institute, artificially-intelligent machines could be designed to destroy lives.

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Artificial intelligence -

Furthermore, even if machines are designed with doing good in mind, there is always the possibility they will stop at nothing to achieve their goal, leaving devastation in their path.

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Unknown threats -

Perhaps the biggest threats facing mankind today are those we are not even aware of yet. As science continues to develop, more threats will emerge that cannot even be predicted yet.

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Unknown threats -

The ability to predict global catastrophes has not always been mankind’s strong point. For example, most people did not predict the explosion of the first nuclear bomb before it happened.

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Unknown threats -

On the flip side, there are some events that have been imagined but which scientists have deemed too unlikely to occur. The possibility of mass extinction caused by a gamma ray burst by a star, for example.

Sources: (Business Insider) (BBC)

See also: What to do if a worst-case nuclear scenario actually happens

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