The AGW hypothesis states that human CO2 emissions will cause the world to warm, with the the globe’s polar areas being especially vulnerable to rapid warming, due to CO2. The evidence from the last 1,000 years plus does not support the hypothesis.
Previously, we examined the data from Antarctica. Now we look at the actual Arctic area data (see chart below) and find that like the Antarctic, the northern polar regions have temperature swings unrelated to the CO2 levels. From peak to valley, Arctic temperatures changed more than 1.6 degrees Celsius while CO2 levels remained fairly stable. (click on image to enlarge)
Despite the alarmist claims of polar regions melting due to CO2-induced warming, there is no evidence to support that claim, either historically or currently. In fact, the highest temperatures reached over the last 1,000+ years were during the Medieval Period (about 1,000 years before present) when CO2 levels were close to being their lowest, based on the ice core data.
Temperature data is from the Greenland GISP II ice core, which ends in year 1905. CO2 levels are from the same dataset used in the previous Antarctica graph.
More historical charts here. Other climate history postings here. Modern temperature charts.