In this video of a presentation given at a climate-skeptic Heartland Institute conference, Don Easterbrook presents his view of recent climate history. He compares his own projections of future climate with IPCC forecasts and claims them to be superior since about 1999.
This comparison has been debunked (see this SkepticalScience post) as a misrepresentation of IPCC results.
But, more interestingly, Easterbrook also presents paleoclimate reconstructions based on oxygen-isotope analysis of ice cores which he claims show both much higher and much lower temperatures in the past 15,000 years than other, more widely accepted paleoclimate reconstructions (the key discussion starts around 3:32 in the video). In particular he claims that the ice-core data are better at showing the well-known medieval warm period and the little ice age than tree ring proxies for temperature but also show periods over the last few thousand years that are significantly warmer than present.
This is clearly a contrarian view compared to the current mainstream consensus on historic climate (often dominated by tree-ring temperature proxies for the last millennium-ish). So are his ice-core based temperature reconstruction credible? and if not, why not?
NB please let's keep the discussion to the question of O2 isotope analysis of ice-core data and not get diverted into ad-hominem attacks on Easterbrook's other opinions.