A couple of graphs are highly illustrative, from an article titled, appropriately enough, When Did Global Warming Begin? at Watts Up With That?.
This graph, generated from ice core data collected at two sites in Antarctica, shows temperature changes over the last 450,000 years. It’s interesting that there have been four sharp rises in temperature prior to the latest one, and each of them has been at least as sharp as the latest one. The latest one also appears to have flattened out at roughly the same levels as, or a bit lower than, those four.
Now see this graph, generated from ice core data collected in Greenland.
The graph axes are a bit hard to read: on the upper graph, the left axis is Air Temperature (oC) at the Summit of the Greenland Ice Sheet, the right axis is Approximate Global Temperature Anomaly (oC); on the lower graph, the left axis is Atmosphere CO2 (ppm—parts per million), the X-axis for both graphs is Years before Now.
In spite of the CO2 panic-mongering, it’s pretty clear that a CO2 rise has been occurring for the last 7,000 years, and that rise is completely unrelated to the warming/cooling spates that have been occurring over the same interval (and the preceding decrease in CO2 levels is similarly unrelated to temperature in that preceding period). In fact, since the temperature peak some 3,500 years ago, successive temperature peaks have been decreasing, even while atmospheric CO2 continues to rise. Some pollutant.
It doesn’t appear very much like humans are impacting Earth’s climate in any significant way, even though we can impact our ecology quite significantly (see the expansion of the Sahara, apparently due to overgrazing, for instance). But climate mongering is an enormous money machine for the climate panickers, far more so than ecology ever has been.