An important new study in “Climate Dynamics” has criticized a key methodology that the Intergovernmental Panel on Climate Change (IPCC) uses to attribute climate change to greenhouse gases, raising questions about the validity of research that relied on it and prompting a response from one of the scientists who developed the technique. The new study’s author, economist Ross McKitrick, told The Epoch Times in an exclusive interview that he thinks his results have weakened the IPCC’s case that greenhouse gases cause climate change. The methodology, known as “optimal fingerprinting,” has been used to link greenhouse gases to everything from temperature to forest fires, precipitation, and snow cover. McKitrick compared optimal fingerprinting to the way law enforcement officers use fingerprinting to identify criminals. “[They] take this big smudge of data and say, ‘Yeah, the fingerprints of greenhouse gas are on it,’” he said. McKitrick said the optimal fingerprinting research he criticized, …