Perhaps I need to explain basic math. The rate of change is the slope of the graph at a given point. Look at the graphs of either carbon dioxide over time or temperature over time and observe how steep the curve is at any given point. That steepness is the rate. To my eye looking over the data graphs, including those at NOAA and NASA, there is no period where the steepness of the curves are anywhere close to the modern global warming event. The nice thing about scientific data is that anyone with basic knowledge can interpret it. Give it a try.

But you certainly don't have to take my word for it or do it yourself. Here is a piece on the unprecedented (in the past 650,000 years) levels and accelerating rate of carbon dioxide. And here is an extensive discussion of the issue (warning: PDF).

The most rapid warming events in the past followed ice ages. These changes took place over approx. 5000 years. The rates I see (roughly) are:

current warming: .74 degrees C in 100 years (mostly in the last 25 years and occurring at an accelerating pace, but let's keep the .74/100 as our rate). That means over the last 100 years the earth has seen a .0074 degree C increase per year on average. Keep in mind this very much underestimates the current rate because 75 of those years was much slower and the last 25 years much faster. But let's accept an underestimate of the current rate just to be conservative.

average warming after glaciations range from 4-7 degrees over 5000 years. Let's again be conservative by overestimating this (and simplify the calculation) by calling it 10 degrees over 5000 years. That is a rate of .002 degrees C per year on average.

This means that the current rate of change is MORE THAN three times the absolute FASTEST ever seen before. Keep in mind I deliberately underestimated the current rate and overestimated the post glacial rate. In itself, this three fold higher rate than ever seen before in the geological record would be worrisome, but not hugely worrisome. But keep in mind that the .002 degrees per year is the FASTEST ever seen before while the .0074 degrees per year is still accelerating.

But again, don't take my calculations at face value. Read the links I gave above and go to the NOAA and NASA websites and look at the raw data. That's what I do frequently. You can also see this breakdown of how no natural influence on climate can account for the current change (thanks John Mashey!).