You are right, but your premise is probably different. They were indeed wrong. They were too conservative. Some historical perspective: 1990: 1st Assessment

You are right, but your premise is probably different. They were indeed wrong. They were too conservative. Some historical perspective: 1990: 1st Assessment Little observational evidence for a detectable human influence on climate 1995: 2nd Assessment The balance of evidence suggests a discernible human influence on global climate 2000: 3rd Assessment Most of the observed warming over the last fifty years is likely* to have been due to the increase in greenhouse gas concentrations * > 66% chance 2007: 4th Assessment Most of the observed increase in global average temeratures since the mid-20th century is very likely* to to the observed increase in anthopogenic greenhouse concentrations * > 90% chance 2016 It is extremely likely** that human influence has been the dominant cause of the observed warming since the mid-20th century. ** > 95% chance 2021: It is indisputable that human activities are causing climate change, making extreme climate events, including heat waves, heavy rainfall, and droughts, more frequent and severe.