Warm air holds more water vapor than cold air does, so the air is more humid than a few years ago. (nydailynews.com)
An example of a feedback is the way a carbon dioxide - rich warmer atmosphere holds more water vapour, which is in itself a greenhouse gas. (realclimate.org)
However, this doesn't account for feedbacks, for example ice melting and making the planet less reflective, and the warmer atmosphere holding more water vapor (another greenhouse gas). (skepticalscience.com)