Can we survive the 21st Centry?

Humanity is facing the sternest test in our million-year ascent. But this isn't a single challenge – it's a constellation of 10 huge man-made threats now combining to imperil our future.

Society regards these risks – ecological collapse, resource depletion, weapons of mass destruction, global warming, global poisoning, food insecurity, population and urban expansion, pandemic disease, dangerous new technologies and self-delusion – as if they were separate issues. In reality, they are intertwined: each affects the others. They cannot be dealt with one by one, but must be solved in conjunction – and at species, not national, level.

Of late, I meet many well-educated, well-informed people – scientists, grandparents and young people especially – fearful that we may be entering the endgame of human history. That civilisation, and maybe even our species, will not survive the compound dangers we are accruing for ourselves. In 'Surviving the 21st Century' I assess the evidence for whether they are right or not.

Drawing on the latest and best science it evaluates each of these risks and also what we need to do – both as a species and as individuals – to avoid them. Finding ways to limit mortal danger is what humans generally do best: that's how we made it through the last million years. Almost certainly, we have the technical ability to do so again. However, on present evidence, our governments, financial and other institutions lack the capacity, wisdom and will to overcome this compound threat. As famed British ecologist Sir David Attenborough warns, many are "in denial" over its sheer scale and speed.

Ignoring existential threats does not banish them. It only renders humanity less prepared. There is no other way to resolve such a complex problem than to face it, to understand it thoroughly, and then take resolute and agreed species-wide action to prevent it.

Here are some examples:

Eco-collapse: Dozens of species are going extinct every day due to human activity. As the world's greatest biologist, E.O. Wilson, warns: "We are tearing down the biosphere" – the very thing that supports life.

The solution is not as hard as some imagine. It is to move half the world's food production into cities using advanced production systems, recycle all nutrients and water, and then "re-wild" about half the land mass under the wise management of indigenous people and farmers. It is to gradually replace mining with mineral recycling, and to cease releasing toxins. It is to replace fossil fuels with renewables. Yet answers like these are still missing in our social and political discourse.

Resource scarcity: Over a lifetime we each use 100,000 tonnes of fresh water, 750 tonnes of soil, 720 tonnes of metals, five billion energy units and emits 300 tonnes of greenhouse gas. No wonder resources are becoming scarce and landscapes worldwide being ruined to obtain them. The self-evident answer is to re-use everything, and then re-use it again. Thanks to technology the "circular economy" is already feasible and becoming profitable. Yet resistance – by political and vested interests – continues to block it.

WMD: The latest climate science indicates it would only take 50-100 small, Hiroshima-sized nuclear bombs to terminate civilisation in a nuclear winter and global famine. World stockpiles currently hold around 15,000 weapons; the risk of them falling into terrorist hands is growing; a new arms race is under way. Nuclear conflict remains the most likely route for civilisation to end – and eight nations now have the power to do it. As the International Red Cross points out, the only way to remove the risk the of such a threat is to eliminate all WMDs and their material stockpiles.

Climate's hidden risk: The release of 2.9 trillion tonnes of carbon dioxide into the atmosphere and oceans by humans will raise the Earth's temperature by +5-10 degrees centigrade. The unseen risk is that, as the planet warms, some of the additional 5 trillion tonnes of frozen carbon (methane) locked in the tundra and seabed will vent, causing "runaway" heating. Scientists say the planet would then become so hot it would be uninhabitable by most large life forms, including humans. The answer is to cease using fossil fuels completely and revegetate half the world's land mass. Green energy is advancing in leaps and bounds and will soon be in a position to take over.

The poisoned planet: Every day, every child on our planet is poisoned by man-made toxins. We, and all life on Earth, are mired in a toxic swamp of 250 billion tonnes of annual chemical emissions from human activity. They are in our food, water, the air we breathe, our homes, vehicles, schools and workplaces, in wildlife, the oceans, in our bodies and even in our genes. Medical evidence is piling up of damage to human intelligence, gender, reproduction and health. There is an answer, though not an easy one: it is for consumers worldwide to reject toxic goods and foods, and to reward companies and farmers who produce clean, safe products. Concerned citizens, parents, cancer societies, doctors, environmentalists and others are already joining hands, worldwide, to forward this goal.