Prior to the immense post-WWII consumer/industrial CO2 emissions, the world was warming, which peaked in the year 1944 (see chart).
The total pre-modern temperature increase to an identified peak (Sept. 1944) was +0.55°C, using the 12-month mean for year 1850 as the starting point.
Since the end of 1944 though, the modern era warming only added another +0.40°C on top of the 1944 peak, based on the high point for the rolling 12-month average, which was reached in mid-1998 (Aug. 1998).
With all the doom and gloom of global warming alarmism, this unexpected truth of modern global warming being less than the pre-modern era is an indicator that man-made catastrophe is not just around the corner. And this good news comes to us from the IPCC's own gold-standard for temperature observations - the UK's HadCRUT4 global dataset.
Also, the above chart of the 12-month means clearly shows a climate that moves from cooling to warming phases, and then back - a natural oscillation that 'catastrophic global warming' skeptics have long discussed, while being dismissed by the IPCC and its cohorts.
Keeping the observed oscillation in mind, the last significant warming ended with a peak in 1998 (the peak during 2010 was a very close second) and temperatures have since paused. Recently, this natural climate oscillation has been identified (by none other than the premier science journal Nature) as a potential cause of the 'Pause' that is generating such befuddlement for the "consensus" climate experts.
Not only has there been a very noticeable pause, since late 2001 there has been an actual cooling of global temperatures, which is noted on the chart with a light blue text box. As for the 12-month 2013 mean, it represents a slight temperature drop of -0.09°C since the 1998 peak (another case of those-stubborn-facts).
Understand, this chart does not explain the amount of any given warming/cooling that is due to either nature or humans, respectively. Nor does it tell us how long the 'Pause' will last or which direction temperatures will take after the stall. Some experts say temperatures will surely fall, while others claim that warming is hiding in the ocean deeps just waiting to climb out - your choice as to which view is correct.
The chart does suggest however that unpredictable temperature movements and climate change will happen regardless of CO2 levels and any human actions.
Finally, many CAGW alarmists predict that global temperatures will jump some 6 degrees by year 2100AD with a doubling of CO2. This chart's axes have been set to provide that context. Per the empirical history since 1850 and the recent global cooling, the 2100AD temp is much more likely to reflect the established +0.47°C per century trend...one thinks.
For those sharp-eyed readers, the chart title has slightly different temperature increase numbers than this article's text. The chart increases are based on the year-end that the peak temperatures took place; the increases used in the text are based on the actual month/year the 12-month mean peak happened.
Note: Excel was used to calculate the 12-month rolling means and plot the data. Used the HadCRUT4 dataset; the post-1958 CO2 dataset; and the pre-1958 CO2 dataset (divided annual ppm levels by 12). Don't know how to chart in Excel? It's easy. Go here to learn how.