On the issue of global warming and its causes, the SPM states that:
- "Warming of the climate system is unequivocal."[9]
- "Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations."[10]
Very likely and likely mean "the assessed likelihood, using expert judgment" are over 90% and over 66%, respectively