It seems more that reasonable to believe that the global climate ball has been given some added weight in the form of added greenhouse gases. (realclimate.org)
Global warming also refers to what scientists think will happen in the future if humans keep adding greenhouse gases to the atmosphere. (vox.com)
Over the last 150 years, humans have triggered climate change by adding greenhouse gases, such as carbon dioxide, to the atmosphere. (sciencenewsforstudents.org)