Oh yes it is, oh no it isn't.

Wattsupwiththat published an article called Changing minds: How do you communicate with climate change skeptics?.

I read down as far as this nugget:

Bargainers are also very strong, adamant deniers of climate change, but they see religion and the environment as more of a negotiated relationship. They take some bits of science and marry it with their faith, but then they ignore the parts of science that don’t support their viewpoint.

They would likely say that rising carbon dioxide levels are really great because that helps plant life grow. It’s true — carbon dioxide does improve plant life — but only to a certain level, which we’ve far exceeded.

That's news to me. Let's see what the professionals have to say about it. From Fifth Season Gardening Co:

If you are green to gardening you might not know that carbon dioxide, the gas we all exhale, is critical to plant growth and development.

Photosynthesis, the process through which plants use light to create food, requires carbon dioxide. CO2 concentration in ambient air ranges from 300-500 parts per million (ppm), with a global atmospheric average of about 400 ppm. If you are growing in a greenhouse or indoors, the CO2 levels will be reduced as the plants use it up during photosynthesis.

Increasing the CO2 levels in these environments is essential for good results. Additionally, there are benefits to raising the CO2 level higher than the global average, up to 1500 ppm. With CO2 maintained at this level, yields can be increased by as much as 30%!