0 A.D. was a bit cooler than it is now. By 1000 A.D. global temperatures had warmed to roughly what we're at now. Then it cooled down again, reaching a minimum somewhere around 1700 A.D. (which, incidentally, is what the global warming apologists frequently use as the pre-industrial average temperature, rather than an unusually cold minimum.) Then it started warming again, until about 1997, when it appears to have leveled off again.
Did Jesus develop lots if industrial technologies that caused a rise in CO2 and a corresponding rise in temperatures for the next 1000 years? Did an economic downturn in 1000 A.D. cause Jesus Industries Inc. to collapse, reducing CO2 output, and thereby cooling the earth off for the next 500 years or so? There must have been a cause, and since we all know that human produced CO2 is the only possible thing that affects global temperatures, that must have been it, right?
When I say the climate has always been in flux, I don't mean we've been in and out of ice ages for millions of years, with a 20,000 year static climate between ice ages, and an 80,000 year static climate during an ice age. I mean it's been in flux. Every single year is either warmer or colder than the year before it. There is not now, nor has there ever been, a static climate on earth. Man-made CO2 global warming models all seem to assume that the climate would be roughly static between ice ages, but for human-caused warming. All evidence points to this assumption being false.