Stephen Hawking died in March at age 76. He was a brilliant scientist and an author of note.

IFOD: Why was Stephen Hawking Famous?

Last month his (supposedly) last book was published called Brief Answers to the Big Questions. As the title suggests, this book focuses on ten big questions facing humanity, including: does God exist, is there intelligent life elsewhere in the universe, how did the universe and life begin, what is inside a black hole and is time travel possible, among others. I thought the book was great (anyway the parts I understood).

One topic he addressed was Will We Survive on Earth? Here’s his take of the big threats facing humanity in rough order of likelihood of threat:

 1. Nuclear War. Dr. Hawking worried that we have become complacent about this risk. He says:

It is without a doubt the case that our world is more politically unstable than at any time in my memory. Large numbers of people feel left behind both economically and socially. As a result, they are turning to populist – or at least popular – politicians who have limited experience of government and whose ability to take calm decisions in a crisis has yet to be tested [and as such] the prospect of careless or malicious forces precipitating Armageddon grows.

2. Asteroid Collision. Dr. Hawking reckons that major collisions with Earth have occurred about every 20 million years and the last major collision was 66 million years ago. Note, that NASA Planetary Defense does track “Near Earth Objects” and is developing measures to “deflect or disrupt an object on an impact course with Earth, or to mitigate the effects of an impact that cannot be prevented.”

3. Climate Change. Hawking’s comment on climate change:

Global warming is caused by all of us. We want cars, travel and a better standard of living. The trouble is, by the time people realise what is happening, it may be too late.

[M]any politicians are denying the reality of man-made climate change, or at least the ability of man to reverse it, just at the moment that our world is facing a series of critical environmental crises. The danger is that global warming may become self-sustaining, if it has not become so already. The melting of the Arctic and Antarctic ice caps reduces the fraction of solar energy reflected back into space, and so increases the temperature further. Climate change may kill off the Amazon and other rainforests and so eliminate one of the main ways in which carbon dioxide is removed from the atmosphere. The rise in sea temperature may trigger the release of large quantities of carbon dioxide. Both these phenomena would increase the greenhouse effect, and so exacerbate global warming. Both effects could make our climate like that of Venus: boiling hot and raining sulphuric acid, with a temperature of 250 degrees centigrade (482 degrees Fahrenheit). Human life would be unsustainable. We need to go beyond the Kyoto Protocol, the international agreement adopted in 1997, and cut carbon emissions now. We have the technology. We just need the political will.

We can be an ignorant, unthinking lot. When we have reached similar crises in our history, there has usually been somewhere else to colonise. Columbus did it in 1492 when he discovered the New World. But now there is no new world. No Utopia around the corner. We are running out of space and the only places to go to are other worlds.

Related:

IFOD on Eco-anxiety

IFOD on what other scientists think are the biggest threat to humanity:  Apocalypse Now

IFOD on an asteroid which passed close to Earth: Florence 3122

Have a nice weekend.