Climate change deniers should be punished, Al Gore has said, adding that politicians in particular should be made to pay a price for rejecting “accepted science”. He stopped short of suggesting what that punishment might be.

Speaking at the South by South West (SXSW) technology and innovation festival in Texas, he told the tech-savvy audience that they should embrace the power of social media to launch a grassroots movement to tackle climate change and call out climate change deniers, EcoWatch has reported.

“We have this denial industry cranked up constantly,” Gore said. “In addition to 99 percent of the scientists and all the professional scientific organizations, now Mother Nature is weighing in.”

He also used his speech to insist that extreme weather events could only be due to climate change, and sought to pin the rise of ISIS in the middle east on global warming.

Andrew Montford, writing on his Bishop Hill blog, commented “No geek or tech shindig is complete without an address from a more or less completely bonkers environmentalist and the South-by South West festival in Austin Texas has gone the full 12-Gore this year.

“It’s always interesting to see what scattergun wildness emerges from the top of Mr Gore’s head. Are polar bears about to sprout flippers and swim off to Clacton? [He] does not disappoint.

“Remind me. Was it Mr Gore who went off to live in a yurt in the north of Scotland or am I thinking of someone else?”

Gore also drew criticisms of hypocrisy for exhorting investors to put their funds in renewable energy schemes, telling his audience that smart investors are moving away from fossil fuels, despite his own investment company dumping millions of dollars worth of green tech shares at a loss three years ago.

“Generation Investment says it is all about climate change, but it is just a typical investment fund with typical stocks,” said Bill Gunderson, President of Gunderson Capital Management at the time.“It has Amazon, Colgate Palmolive, eBay, Nielsen, Qualcomm, Strayer University and a smattering of stocks from biotech and health care. Not one company that makes solar panels, or windmills or bio-gas or electric cars. Catheters and commercial real estate, yes. Solar panels, no.”

As the cost of gas and coal drops whilst subsidies are increasingly difficult to come by, renewable energy is becoming an increasingly poor investment. Generation Investment lost tens of millions of dollars on First Solar, selling 1.12 million shares for $28 million just two years after buying 440,000 shares in the company for $65 million.

It also had holdings in SunTech, EcoSynthetix, Landi Renzo and Meyer Burger, all of which lost between 25 percent and 88 percent of their worth in 2012.

“I don’t blame Gore for getting out of alternative energy,” Gunderson said, “even if he did it too late in the case of First Solar. But when is he going to tell people that alternative energy is a lousy investment?”

Despite this, Gore told the SXSW audience that more investment into the renewable energy sector was to be encouraged, lending his support to a proposed federal cap and trade system. “We need to put a price on carbon to accelerate these market trends. And in order to do that, we need to put a price on denial in politics,” he said.

The speech took a bizarre turn at one point when Gore showed a slide of the current Pope, asking the audience “How about this Pope?”

According to the Chicago Tribune, Cardinal Peter Turkson, a Vatican official who has helped to draft an upcoming encyclical on the environment, due in June or July, said recently that the planet was warming and that Christians need to do more to address the problem.

“I’m not a Catholic, but I could be persuaded to become one,” Gore said.