“Averaged over all land and ocean surfaces, temperatures warmed roughly 1.53°F (0.85ºC) from 1880 to 2012, according to the Intergovernmental Panel on Climate Change (see page 3 of the IPCC’s Climate Change 2013: The Physical Science Basis, Summary for Policymakers – PDF).”
HOWEVER, according to NASA, “The connection between solar activity and terrestrial climate is an area of on-going research.” This connection may still be poo-pooed by the IPCC, but after rigorous statistically analysis, it’s withstood the test of scrutiny and has entered mainstream science. Adds NASA: “Early records of sunspots indicate that the Sun went through a period of inactivity in the late 17th century. Very few sunspots were seen on the Sun from about 1645 to 1715 (38 kb JPEG image). Although the observations were not as extensive as in later years, the Sun was in fact well observed during this time and this lack of sunspots is well documented. This period of solar inactivity also corresponds to a climatic period called the “Little Ice Age” when rivers that are normally ice-free froze and snow fields remained year-round at lower altitudes. There is evidence that the Sun has had similar periods of inactivity in the more distant past.”
Source: NASA’s Solar Science Website on The Sunspot Cycle
Getting back to the IPCC’s arbitrary selection of 1880 as a starting point… The temperature in 1880 was significantly lower than mean over the last 2000 years. For example, it was a good 0.5 deg C (0.9 deg F) warmer throughout the several hundred year long Medieval Warm Period than it was in 1880. Thus, to be objective, selecting the mean over the last 2,000 years, we find the temperature rise in recent years isn’t nearly 1.53 deg F, but rather, closer to 1 deg F, well within normal variation. Furthermore, in the last 15 years, the temperature has not adhered to the IPCC predictions, instead rising just 0.2 deg F.
When you expand the time window out to, say, 50,000 years, we find that recent changes are miniscule compared to recent times. We find temperatures were 1.5 deg C warmer than they are today during the Medieval Warming period approximately 1,000 years ago; 2.5 deg C warmer than they are today during the Roman Warming period approximately 2,200 years ago; and 3.25 deg C warmer than they are today during the Minoan Warming period approximately 3,350 years ago. Temperatures were as also hot as they were during the Minoan Warming period back around 7,000 years ago as well as 7,800 years ago. We’ve also had mini-ice ages, around 8,300 years ago, 4,700 years ago, and 1,200 years ago.
These facts match an earlier release by NASA scientists entitled, Anthropogenic Global Warming Science Assessment Report.
So – What does all this mean? How does the modern rise stack up against the much larger swings throughout the last 10,000 years?
Answer: It’s nothing but a blip. At least twelve rises over the last 10,000 years have been several times greater than the modern rise. See for yourselves: