I felt the problem with the CO2 treaty is that the so called 3rd world nations were not held to it, why just move the problem there.
China puts a little over 22% of the man made CO2 in to the air and they are the number one producers in the world.
The US with as you said only 300 million people puts about 19.9% and we are the second largest producers. But we also consume a lot of goods from China.
India puts out 5.5% to be the third producer of CO2.
I think Russia is next with about 5.4%
Washington DC puts out 32% of the nations hot air.
Fox puts out the rest.
I would think at a garden forum people would be very aware of the weather, climate and the ability to grow crops.