A 2013 study (following a 2004 study), quantifying the consensus on the link between anthropogenic greenhouse emissions and global warming, found that 97% of studies agreed humans were causing global warming. As of last week, it reached over 1 million downloads. However, up until last year, approximately 10% of Canadians believed that climate change is a theory that has not been proven and another 20% believed it is was a result of natural causes.