University of California physics professor Richard Muller, one of the most vocal sceptics, gathered a team of 10 scientists, mostly physicists, including 2011 Nobel Physics Prize winner Saul Perlmutter, to create the Berkeley Earth Project.
Bob Ward, policy and communications director for the Grantham Institute for Climate Change and the Environment in London, told the BBC he's ready or apologies, including one from Republican presidential candidate Rick Perry, who has accused scientists of manipulating data.
"So-called 'sceptics' should now drop their thoroughly discredited claims that the increase in global average temperature could be attributed to the impact of growing cities," he said.
"More broadly, this study also proves once again how false it was for 'sceptics' to allege that the e-mails hacked from UEA proved that CRU land temperature record had been doctored.
"It is now time for an apology from all those, including US presidential hopeful Rick Perry, who have made false claims that the evidence for global warming has been faked by climate scientists."
Add this new study to your points on how to talk to a climate change sceptic. And maybe punctuate it with your middle finger.