we don't deny it, we deny that humans have any significant impact on it...
the average co2 content of atmosphere is 0.04% (400ppm), humans contribute about 10% of that; and that figure hasn't changed in 70-80 years.
It's amusing to me that greenies drive around in their electric cars patting themselves on the back thinking they're saving the world, when they still buy 99% of their shit from China, which couldn't give two shits about pollution and has four times more coal plants than the rest of the world combined (1100-1200)