The State Department of Natural Resources recently scrubbed language from an agency web page on the Great Lakes that said humans and greenhouse gases are the main cause of climate change. The DNR now says the subject is a matter of scientific debate. The department made the changes on Dec. 21, striking out whole sentences attributing global warming to human activities and rising levels of carbon dioxide. It’s the most recent example of the DNR removing information related to climate change. More broadly, the changes reflect how the administration of Republican Gov. Scott Walker has de-emphasized the subject since he took office in 2011.