What Evidence Would Persuade You That Man Made Climate Change Is Real?

This is source I found from another site, main source you can find in last paragraph

Al Gore recently had a telling altercation with a journalist. The Spectator’s Ross Clark wanted to ask him about Miami sea-level rises suggested in the new film, “An Inconvenient Sequel.” The reporter started to explain that he had consulted Florida International University sea-level-rise expert Shimon Wdowinski. Gore’s response: “Never heard of him — is he a denier?” Then he asked the journalist, “Are you a denier?”

When Clark responded that he was sure climate change is a problem but didn’t know how big, Gore declared, “You are a denier.”

I was recently on the receiving end of a similar rebuff from Chile’s environment minister. I’d written an op-ed for a Chilean newspaper that, among other things, quoted UN findings on how little the Paris climate treaty would achieve and argued that vast investment in green energy research and development is a better policy. Marcelo Mena proclaimed, “There is no room for your climate-denying rhetoric in Chile.”

Something odd — and dangerous — is happening when even people who accept the reality of man-made climate change are labeled “deniers.” The unwillingness to discuss which policies work best means we end up with worse choices.

Consider the case of Roger Pielke Jr, a political scientist who worked extensively on climate change. He believes that climate change is real, human emissions of greenhouse gases justify action and there should be a carbon tax.

But he drew the ire of climate campaigners because his research has shown that the increasing costs from hurricane damage are not caused by storms made more intense by climate change but by more and pricier property built in vulnerable areas. He took issue with the UN’s influential International Panel for Climate Change over a chart in its 2007 report that seemed to imply causation when there was only circumstantial evidence.

Pielke was proven right, and the IPCC’s subsequent outputs mostly accepted his arguments. Yet he was the target of a years-long campaign, including a massive but baseless takedown that later turned out to have been coordinated by a climate-campaigning think tank funded by a green billionaire, alongside an investigation launched by a congressman.

Pielke left climate change for other fields where “no one is trying to get me fired.” And sidelining him has made it easier for climate campaigners to use Hurricanes Harvey, Irma and Maria to argue for carbon-cut policies, even though these will do very little to prevent future hurricane damage.

Pielke finds that we should make relatively cheap investments to reduce vulnerability, like limiting floodplain construction and increasing porous surfaces. Ignoring this means more harm.