My previous article here was about the NH Summer energy driving the changes in the Earth’s climate. I used ice core data to show that Greenland and Antarctica both warmed after the NH summer energy started increasing 18,000 years ago. I have also discussed that ice cores give more of a regional temperature indicator than a local indicator here.
If both of those are correct, then the temperature of the Northern Hemisphere (NH) should be shown to be warmer in the past than it is now. A recent paper (Sundqvist, Zhang, Moberg 2010) says just this. It focuses on the two time periods of 6,000 and 1,500 years ago and uses 104 temperature reconstructions from around the Arctic region to determine the temperature at those two times. It also provides some results for the differences between 6,000 years and 500 years ago. Due to limitations in the data the overall results are for the 6,000 and 1,500 years ago.
Here are the results for 6,000 and 500 years ago.
The overall conclusion is:
“A large majority of the here investigated temperature
reconstructions indicate that temperatures were warmer at
the mid-Holocene (6000 BP ± 500 yrs) compared to the pre-
industrial period (1500 AD ± 500 yrs), both in summer, win-
ter and the annual mean. By taking simple arithmetic aver-
ages over the available data, the reconstructions indicate that
the northern high latitudes were 0.9 ◦ C warmer in summer,
0.5 ◦ C in winter and 1.7 ◦ C warmer in the annual mean tem-
perature at the mid-Holocene (6 ka) compared to the recent
This study supports the overall idea that the long-term trend for the NH has been cooling for the past several thousand years. It does not go into the variability in temperature, but it is a good indicator that cooling has been occurring. This also supports that the Arctic region and the animals that live there are fully capable of surviving the current temperature.
As I have stated many times before. The Earth is always changing. The biggest adjustment that is needed is to our perspective. We must understand that the Earth does not stay the same. Ignoring the natural changes of the Earth makes it impossible to understand it.