But CO2 does cause warming. If I drop a cloche over my tomato starts today, the air around them warms, not because the sun is any brighter or because the sun is any closer, but because the heat, the same heat, radiating from the ground is trapped, slowed by the glass. Thus CO2, which demonstrably traps and slows the radiation of heat, does cause warming.Quote from jem:
That is what I have been telling you. There is no evidence co2 is causing the warming...
Now, let's say I leave the cloche there "forever". Variations in solar output and Earth's orbit will change the interior temperature of the cloche. Without further variables added, this cycle will continue so long as the cycles of sun and orbit continue. But suppose I come along and add a slightly larger cloche over the first, in effect creating a double-walled mini-greenhouse. Now the insulative effect of the cloche is greater, and the temperature inside will rise still more, and it will be trapped longer.
This is why, if you can afford it, you want a double-walled greenhouse instead of single-walled.