Is water vapor more responsible for climate change than carbon dioxide?

Water vapor is a climate feedback rather than a climate forcing, meaning that it does not initiate warming, but instead amplifies existing warming from another source.

It is true that water vapor is the most abundant greenhouse gas in the atmosphere and responsible for a majority of the greenhouse effect. However, atmospheric water vapor cannot increase until temperatures first rise to facilitate more evaporation of water vapor into the atmosphere.

In modern times, carbon dioxide emissions from human activities such as burning fossil fuels and deforestation are responsible for the initial warming that began during the Industrial Revolution.

According to NASA, “water vapor is potent enough to double the climate warming caused by increased levels of carbon dioxide in the atmosphere.”