Wierd, coulda sworn there was a post here a moment ago saying something about the ice age start date, been Googling? ....
Just wrong. Borehole proxies work by actually measuring the current temperature at various depths and adjusting for upward heat flux (read the paper!), nothing to do with isotopes. Ice cores work by analysing the composition of ice bubbles trapped at various depths. The borehole data goes up to present day, albeit with decadal resolution, the ice cores, well just one more thing that Easterbrook gets wrong:
Here's another Easterbrook special
You'll notice that
- He has 10K years ago warmer than today, as opposed to -2C in the borehole data,
- He has no idea when the MWP was, and
- His 'present day' temps are just nuts.
Apart from that, a perfectly informative graph.
Sure you want to champion this guy?
The bore hole/ice core data reconstructs the data to 1995 to be exact. The fact that they have analysed temps from the ice, using Oxygen isotopes up until the present time makes a complete mockery of the assertions on Skeptical Science that it isn't possible, i.e. the data only goes up until 1855. It quite obviously doesn't.
Easterbrook plots the temperature data from the GISP2 core, as archived here. Easterbrook defines “present” as the year 2000. However, the GISP2 “present” follows a common paleoclimate convention and is actually 1950. 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. In order to make absolutely sure of my dates, I emailed Richard Alley, and he confirmed that the GISP2 “present” is 1950, and that the most recent temperature in the GISP2 series is therefore 1855.
You'll notice that
- He has 10K years ago warmer than today, as opposed to -2C in the borehole data,
- He has no idea when the MWP was, and
- His 'present day' temps are just nuts.
Apart from that, a perfectly informative graph.
Sure you want to champion this guy?
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