The Next Mass Extinction Has Begun

There have been five major mass extinction events in Earth's past. During each one more than 70 percent of all species were wiped out.  One of them, the Permian-Triassic event 252 million tears ago, actually killed off about 96 percent of all species.

Most of the events were caused by a significant climate change brought on by a combination of volcanic activity, asteroid impacts, sea level changes and drops in oxygen levels. The most recent mass extinction - the Cretaceous-Paleogene event 66 million years ago - is thought to have been almost entirely due to a massive asteroid strike known as the Chicxulub Impact, on Mexico's Yucatan Peninsula. It has become the most well-known of all extinction events, primarily because it caused the extinction of the non-avian dinosaurs. The dust cloud created by the impact reduced global temperatures by several degrees for decades. After that there was a period of rapid warming due the huge increase in carbon-dioxide in the atmosphere. For up to 100,000 years the global temperature was an average of five degrees higher. There was little time for most species to adapt.

An artist's impression of the Chucxulub impact crater a few hundred years after the asteroid hit. The crater is about 150 kilometres in diameter, and up to 20 kilometres deep.

There will be another mass extinction event - a sixth massive reduction in the number of species living on this planet. That extinction event, known as the Holocene extinction, is already under way, and its cause seems to be exclusively linked to human activity.

Humans have been responsible for extinctions for many thousands of years. The mammoth, which had been in decline as a species since the end of the last ice age more than 11,000 years ago, is one of the first examples. It was finally hunted to extinction 5,000 years ago. This was the start of our destruction of our planet's ecosystem.

Over the last century our rapid advance into a global technological civilisation, and our massive population growth, has lead to extremes of habitat destruction, over hunting, pollution and subsequent climate change. Without a drastic change to our activities most species will be extinct within a few centuries. Humans will have caused the fastest and most extreme mass extinction ever known on this planet. And it is more than possible that our own species will be one of those driven to extinction as the ecosystem we rely on collapses.

To survive as a species we need to do two things. And we need to do them now.

1. Halt our Destruction of Earth's Ecosystem

An extreme level of cooperation between the governments of the world's nations is required if we are to stop, or even just slow down, the climate change caused by our activities. And that cooperation needs to start this year. Unfortunately, as always, governments seem preoccupied with political, economic and territorial disputes. Climate change, and its effect on our very survival as a species, seem to be far down the list of priorities.

Radical policies are needed, with developed countries pushing for the complete replacement of fossil fuels with clean energy generation within a decade. Nuclear energy, despite its controversial nature, is very clean compared to coal and gas burning. In fact, nuclear energy generation produces zero emissions, and very little waste due to the density of nuclear fuel. The land required for a 1,000 megawatt nuclear energy generator is only about one square mile, compared to 75 square miles for the equivalent solar power plant. As well as building many more nuclear power stations, solar and wind power generators should, of course, be expanded rapidly, too. This will accelerate the closure of coal and gas power stations.

The massive and ever increasing human population on Earth needs to be ethically controlled. Developing countries in particular need immediate help to remove the need for people to have more than two children. If population growth is not controlled it is predicted that there will be almost ten billion people living on this planet by 2050 (up from 7.6 billion now). The demand on resources is already unsustainable. With such an increase we are condemning billions to starvation.

2. Build Self-Sufficient Colonies Away From Earth

The creation of self-sustaining colonies away from Earth should have started decades ago, but at least there seems to have been some recent minor progress towards such colonies. NASA have brought forward plans to get humans back to the Moon. It will create a sustainable human presence on the Moon by the middle of the next decade, and the Gateway, a space station in orbit around the Moon, will be a staging post for crewed missions to Mars.

NASA's space station orbiting the Moon. Construction is expected to start as early as 2022. It will be used as a staging post for Moon landings, and as a stepping stone to Mars.

While NASA does not seem to have much of a timeline beyond for the crewed missions to Mars (other than 'sometime in the 2030s') the plans for the Moon seem to be quite well defined, and impressively ambitious. The resources of the Moon can and will be used to manufacture the fuel for future missions to Mars.

This relatively sudden new momentum is encouraging, and must continue.

As soon as a permanent settlement is established on the Moon the missions to build one on Mars must begin immediately. No time can be wasted. And as the Mars colony grows in the 2030s there must then be a push to establish colonies further afield, such as on Jupiter's moon, Callisto (which orbits outside of Jupiter's harsh radiation belt - see 'Humans on Callisto within 15 Years'), and on Saturn's moon, Titan. Despite the extreme cold Titan is particularly suitable for a very large human colony - see my article, 'Human Colony on Titan' for more on that subject. In fact, it seems to be one of the best places to create a very long term human presence.

There must also be space-born colonies: vast habitats that do not rely on a planetary body and that can exist in their own independent orbits around stars and in interstellar space. They would obtain all the resources they need from small asteroids and comets, found abundantly for example in the Kuiper belt and the Oort cloud.

Will this century be the last time we'll be able to look down on Earth from space? Is the damage to the environment and climate caused by human activity already beyond recovery? If so, our technological civilisation will soon end.

If we do nothing to limit the effects of the current extinction event then we certainly deserve our fate. If our species becomes extinct then at least our destructive activities will cease. Earth will begin a slow recovery and a new climate equilibrium will allow a host of new species to flourish. Over many millions of years the Earth will become a thriving and lush haven for life, at least until another highly intelligent species starts to dominate and abuse its environment.

Is it possible that some of the many smaller spikes of extinction and climate change in Earth's past were caused by a dominant intelligent species that brought about their own demise? We could simply be continuing a natural cycle of events that has already played out on this world and millions of others. That cycle needs to be broken right now, before we doom yet another of Earth's civilisations to oblivion.