Temperatures are rising after the Little Ice Age (LIA) a few hundred years ago. How much of today’s temperature levels are natural recovery from the LIA and how much are due to human CO2 release, he asks. "They can’t even really quantify how much of the CO2 with the fossil fuel 'signature' is even actually released by human activity and how much is natural from such things as global coal seam and gas pit fires."
But why choose the LIA as their starting point anyway? There have been other cold periods and other recoveries. "There were cold periods during the Roman Empire that caused great migrations of people. Why did the Visigoths migrate South from Sweden? Why did the Vandals migrate South from the Baltic? Because it got too COLD there!"
Then he turns to the medieval warm period (MWP).
They would also claim the MWP doesn’t exist and say they can’t find the tree ring signal for it. We don’t NEED a tree ring signal, we have chronicles of the time that report what was being grown and where it was being grown. We know that in many places in the Alps, Scandinavia, Greenland, and other places, some things that were being grown in various locations can not be grown today because it is still too cold in those places.“The Cause”, he says, would write this off to local circulation changes.
Problem is that we see evidence for the MWP in Alaska, the Sierra Nevada, the Great Basin, South America, and Africa, too.Now comes the crunch point. To top it all off, they have picked some arbitrary fairly recent period to represent “normal” temperatures when that recovery from the LIA might not even be complete yet.
It might even take the oceans another few hundred years to fully recover at depth and so they are going to be rising as the water undergoes thermal expansion and they will also release more CO2 as it warms at depth.And, he concludes, "if word were to get around that maybe what we are seeing is a natural recovery of temperatures, what would happen to these people's careers?
Others have asked, if we really could engineer the global climate (ha ha) and keep it stable (ha ha), would we choose present temperature levels? The world might well be better off a few degrees warmer anyway.