Former US President Bill Clinton has warned that global warming presents a bigger long-term challenge to the world than international terrorism.
Bill Clinton addressed 800 people at a hotel in central Glasgow
During an engagement in Glasgow, Mr Clinton said the problem could transform life on earth.
Mr Clinton said countries now had an opportunity to create high-calibre jobs in finding alternative energy sources.
He addressed 800 business people in Glasgow. Each table of 10 cost £5,000 for lunch with the former US leader.
Mr Clinton also used part of his speech to praise the power of the internet as a force for change.
The visit was partly brokered by former Rangers winger Brian Laudrup, who has played golf with Mr Clinton and is linked with a celebrity events company.
The 42nd US president - who left the White House in 2001 after two terms in office - was introduced by First Minister Jack McConnell.
Entrepreneur Tom Hunter, who donated £55m to the new Clinton-Hunter Development Initiative, was also present.
During his speech, Mr Clinton said that the most profound threat to the way of life in the UK and US was not terrorism but global warming.
He said: "There may be other terrorist attacks. Some of the attacks over the next 20 years may involve small-scale chemical, biological or nuclear materials but there has never been a nation destroyed by terrorism alone.
"It is not about to start now.
"But I think this climate change has the capacity to change the way all of us live on earth."
He later added that there were great opportunities in the development of clean energy sources.
In a response to a question from the chairman of the Scottish Environment Protection Agency, Sir Ken Collins, he said: "If I was 25 again and I was setting up a career in the private sector, not as a public servant, I would go into clean energy.
"I would be a billionaire before you could turn around."
Mr Clinton's visit provoked protests from some groups.
Andy Gunn, who contracted HIV and hepatitis from infected blood products, said that while Mr Clinton was governor of Arkansas, contaminated blood from prisons was exported to other countries.
He said: "They were making a lot of money. In fact, blood was worth more in weight than gold at the time.
"They knew the blood was infected with HIV and hepatitis and the prisoners were themselves dying of these conditions.
"It was actually illegal to use the blood in America and they secretly sent it up to Canada where it was turned into Factor VIII and punted around the globe."