claim: Water vapor helps trap heat, and is a far the strongest of the major greenhouse gases, contributing 36–72 percent of the greenhouse effect.
evidence: In November 2017, a second warning to humanity signed by 15,364 scientists from 184 countries stated that "the current trajectory of potentially catastrophic climate change due to rising greenhouse gases from burning fossil fuels, deforestation, and agricultural production – particularly from farming ruminants for meat consumption" is "especially troubling".