Dating age range graph
The difference is estimated to be 0.9ºC on the annual average (Box, pers comm).
Let’s have ago at reconstructing Easterbrook’s Fig 5, covering the last 10,000 years of GISP2 data.
It also reflects regional Greenland warming, not global warming.
Most of the last 10,000 years were warmer Even if the warming were as big as the IPCC imagines, it would not be as dangerous as Mr. After all, recent research suggests that some 9,100 of the past 10,500 years were warmer than the present by up to 3 Celsius degrees: yet here we all are.
Here’s what he had to say: The contention that the ice core only reaches 1905 is a complete lie (not unusual for AGW people).
The top of the core is accurately dated by annual dust layers at 1987.
Richard Alley discussed that in some detail at Most of the past 10,000 [years] have been warmer than the present.
The first data point in the file is at 95 years BP.
This would make 95 years BP 1855 — a full 155 years ago, long before any other global temperature record shows any modern warming.
The two blue crosses on the chart show the GISP site temperatures (adjusted from GRIP data) for 18.
It’s clear there is a calibration issue between the long term proxy (based on ∂O measurement) and recent direct measurement of temperatures on the Greenland ice sheet.