It isn't steady.
And this:
"In order to focus on you and what you are doing to increase the CO2 in the atmosphere, which, as everyone knows will destroy the globe, we do not discuss the activities of termites. Fifteen years ago it was estimated that the digestive tracts of termites produce about 50 billion tons of CO2 and methane annually. That was more than the world's production from burning fossil fuel. Additionally, cattle, horses and other ruminant animals are huge producers of both CO2 and methane, but, being unable to respond to our demands on this issue, their activity is ignored. "
There were termites and ruminants around for a long time. But massive use of fossil fuels as well as large scale deforestation only counts for a few hundred. By the way, a horse is not a ruminant, which tells a bit about the quality of this rather common statement.
Here is a simpler statement.
It is known that an increase in greenhouse gas % will lead to heating. It is also known roughly how much we release, and golly it is actually measurable. And now, starting to be viewable. So, why be surprized?