There isn’t yet any empirical evidence for their claim that greenhouse gases even cause temperatures to increase.
Some scientists propose that greenhouse gases act like a blanket surrounding Earth, keeping Earth approximately 33 oC warmer than expected for a planet at Earth’s distance from Sun. Blankets are well-known to slow the loss of thermal energy from a body of matter, but a blanket has no way to increase the amplitudes of oscillation at every frequency of oscillation. A blanket cannot be the source of new thermal energy required to increase the temperature of the body under the blanket, unless it is an electric blanket that adds thermal energy from somewhere else. [...] What is most surprising, given the importance of greenhouse gases in today’s politics, is that greenhouse gases absorbing infrared radiation have never been shown by experiment, a cornerstone of the scientific method, to cause any significant increase in air temperature as explained at JustProveCO2.com. Greenhouse gases absorbing infrared radiation have never been shown by experiment to cause any significant increase in air temperature.