What if humanity goes extinct?

The closer the hands of the doomsday clock are to midnight, the worse it would be for humanity. Although the imaginary clock has stood still for about four years, yesterday the scientists gave the hands a twist. Closer to midnight actually. Which brings us to the question: what if humanity actually destroys itself and becomes extinct?

Suppose the man suddenly disappears. The first thing that happens is that the earth becomes one big crash site. Cars collide, planes fall from the sky. Within hours, power plants will shut down when fuels are no longer supplied. Oil refineries and chemical plants are becoming ticking bombs. When the power goes out and the pressure is too high due to overloading, devastating fires occur, sending toxic junk such as hydrocyanic acid and dioxins into the air. And we are not even talking about the tanks in which liquid fuels are stored at high temperatures. When the soil rusts through due to lack of maintenance over time, the toxic content seeps into the soil.

But that is not the only danger to nature. We are also leaving behind hundreds of nuclear power plants. After more than a week, an inevitable disaster process sets in motion. Because the water in the cooling basins is no longer replenished and the safety equipment no longer works due to lack of power, the water will boil and evaporate. At some point, the vapor reaches the spent fuel in the storage areas, which then catches fire. The resulting radioactive fire will eat away at the top of the reactor within hours, after which the core will begin to melt: a meltdown. The overheating of the fuel tanks causes explosions and the disaster is complete.

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Green oasis

Time bombs, chemical factories and nuclear power plants alike wreak death and destruction within a radius of a few 10 kilometers with their suffocating toxic fumes, radioactivity and explosions. Still, nature gets over this blow surprisingly quickly. It can be seen, for example, after the nuclear disaster in Chernobyl in 1986. “The final effect is positive for plants and animals, if you look at the number and diversity of species,” says environmental biologist Ronald Chesser. He investigates how nature recovers in the reactor area. “In Chernobyl itself, you now see cherry trees with delicious cherries and rose trees with evil spikes that have grown to gigantic sizes. In all 126 destroyed villages around the power plant, you will find bats in apartments, falcons roosting on balconies, wild boars roaming gardens, and foxes and wolves sheltering in cellars.”

As humans die out, oil refineries pose a threat to nature by releasing all kinds of toxic gases and liquids. ©Getty Images

In short: If humans die out, the earth becomes one big, green oasis. It already starts with the agricultural and livestock areas, with which we have covered more than a third of the earth’s surface. An experiment at the end of the nineteenth century in Rothamsted, England, showed what happens when people completely leave a piece of winter wheat field alone. The wheat continued to sprout spontaneously for another five years, but bear’s claw appeared after only two years. Within ten years, seedlings of hazel, ash and oak began to take root. Now there has been a dense forest for more than a hundred years. Largely a patchwork of agricultural and livestock land, Europe is expected to turn back into primeval forest within a thousand years, as it was a few thousand years ago.

Entire cities cannot escape the invasion of nature after man has disappeared. It starts with weeds, followed by fast-growing (especially exotic) plant species from gardens and parks, such as the Chinese tree of heaven, and then trees such as oak and maple. They begin to grow out of holes in the streets, and later out of the houses themselves. Animals, big and small, find shelter in all kinds of buildings.

Art as a meal

Still, it’s only a matter of time before the animals have to give up their hiding place. Our structures all collapse at some point. It starts with the roof. The supporting structure of the tree is inevitably affected by moisture and mold and collapses within fifty years of man’s passing. Brick and concrete walls are also ravaged by wind and weather, after which more and more cracks appear. Entire skyscrapers fall in less than a century.

In cities such as London, Moscow, New York and Washington, the underground tunnels collapse within twenty years. Because the pumps no longer work, the bottom water comes to the tunnels. After the road surface gives way, the streets will turn into rivers. Human monuments such as the Eiffel Tower in Paris cannot escape decay either. After two centuries, the rain has washed away the protective paint from the tower and the elements have free play on the metal frame. A century later, French pride is collapsing like a house of cards.

If humans die out, most art will perish.  Earthworks like this Buddha statue will last a long time.
Most art quickly perishes without the presence of man. One of the exceptions is earthenware items like this Buddha statue. As long as they remain intact, of course. ©Getty Images

Art is doomed. There is climate control in museums, but without electricity, the way is free of moisture, mold and the black carpet beetle to eat its way through paintings and other works of art. Anything stored electronically, on DVDs or hard drives, will also suffer.

Is there anything left of our human existence? Yes; anything made from precious metals, such as gold and platinum, will last forever, as will ceramic products (made from minerals). Bronze statues will also last a long time. But one typical human product in particular is indestructible: plastic. Over time, microbes will learn to digest the plastic – as they once did with plant fibers – but this could take more than 100,000 years.

Greenhouse ventilation

Plastics are not the only products of mankind. Greenhouse gases, of which carbon dioxide is the most important, are also greenhouse gases. We pump about 37 billion tons of carbon dioxide into the air every year. With global warming and a rise in sea level as a result. But what happens to the greenhouse effect when humans die out and therefore never burn coal, petroleum and natural gas again?

“In the next few hundred years, about 80 percent of all the carbon dioxide we have produced since the 18th century will dissolve in the oceans. This results in ocean acidification,” says Dutch climate scientist Pieter Tans, who works at the US NOAA. The remaining 20 percent must be dissolved in the ocean in another way, he explains. “The dissolved carbon dioxide in raindrops reacts with limestone, the petrified remains of marine animals. This results in a larger amount of lime in the ocean, which neutralizes acidification. This is a very slow process; it may take 100,000 years for carbon dioxide concentrations to return to pre-human levels.”

When people die out, rusty train cars are common
An overgrown track with rusty train cars will be a common sight decades after man has disappeared. ©Getty Images

But humanity has caused much more changes to the atmosphere than just extra carbon dioxide. “There are more than a dozen industrial gases,” says Tans. “Some of them have contributed to the thinning of the ozone layer, others are very toxic and many are also greenhouse gases. Some disappear within ten years, others remain in the atmosphere for thousands of years.” So it takes some time, but then you also have something: clean air and a natural climate. A relief for plants and animals.

A new world

Now that plants and animals have the kingdom all to themselves, the question is how they will evolve over time. Suppose we all move away from earth now and come to see in five million years. “I expect that 95 percent of the plant and animal species will be largely the same as today. The rest will have adapted to the environment in amazing, often unpredictable ways,” says environmental biologist Chesser.

“Herbivores will come in gigantic herds because they have much more space to graze on than before humans became extinct. Predators will therefore have the greatest urge to adapt. I expect large birds to come hunting in flocks. They won’t be able to fly, but they have terrifying beaks and sharp claws to bring prey down together.”

One of these amazing new species could become intelligent; perhaps as intelligent as man. That would give us a new dominant species on Earth. However, a few conditions are required. First, it must be a social species, animals that communicate and work together. In addition, they must also have the opportunity to learn how to use tools to bend nature to their will. “Based on that, apes have the upper hand with their intelligence and potential technological development,” says Chesser, “but birds don’t fare any better. They have a complicated social structure, are above average intelligent, and cleverly use twigs and the like to get food. I think crows and ravens in particular have a good chance.”


Millions of years after we are extinct, very little of the human glory will remain. A future dominant and intelligent species would only find bones, plastic parts, jewelry and ceramic products (if not broken) from us. A desolate prospect for man, but a great victory for nature.

This article was also in KIJK 3/2014.

Picture (main): André Kesseler

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