By Anders Lorenzen

The British theoretical physicist, cosmologist and author Stephen Hawking died last week.

He was much loved in Britain and around the world. He rose to fame because of his theory of black holes called the Hawking radiation, and because he had lived since his early 20s with motor neurone disease which paralysed him. When first diagnosed he was told he would die at age 23. When he died this week he was 76.

While it did not dominate his work, he was a strong advocate for action on climate change. But he was very pessimistic whether we could deal with this problem, and worried that we had acted too late. He believed, that in order to keep our options open and to save humanity from climate change and other catastrophic natural events, we should start to cultivate other planets. He warned that Earth could eventually turn into Venus, which had experienced runaway climate change earlier in its history.

He made that comparison as an example of what could happen to our planet, if there is a lack of serious action, and greenhouse gases continue to grow unhindered. Our planet could be like Venus, he explained. It could reach a tipping point, with a temperature of perhaps 250 degrees and raining sulphuric acid. For that reason, he wanted to send climate deniers, for whom he had no time, to Venus, and he even offered to pay for their journeys so they could experience the impact greenhouse gases would have on a habitable planet.

Hawking’s strongest opinions about climate change came in his later years, almost as if the older he got, the more worried he became about the issue.

Hawking believed climate change to be one of the biggest threats facing humanity, and he was particularly concerned over US President Donald Trump`s disregard for the issue and his policy to pull the US out of the Paris Agreement. In January he said about the move: “I am not denying the importance of fighting climate change and global warming, unlike Donald Trump, who may just have taken the most serious, and wrong, decision on climate change this world has seen.”

For Hawking, space exploration had become a climate adaptation necessity: “We must continue to go into space for the future of humanity. I don’t think we will survive another 1,000 years without escaping beyond our fragile planet,” he said.

But he was optimistic that mankind would be able to achieve this, saying: ““Perhaps in a few hundred years, we will have established human colonies amid the stars”. But he was adamant that until then we must take action to prevent the worst impacts of climate change: “right now we only have one planet, and we need to work together to protect it. To do that, we need to break down, not build up, barriers within and between nations.”

Apart from his major contributions to science and the scientific community, Stephen Hawking leaves behind three children.