One of the big selling points of Al Gore’s alarmism is worldwide glacier retreat. “Everywhere in the world the story is the same,” he says, “including in the Andes in South America.” He shows a picture of the Qori Kalis glacier in Peru, showing undeniable retreat in the past fifteen years (see p. 52-3 of the book version of An Inconvenient Truth).

Inconveniently, it seems that Andean glaciers have retreated and advanced many times in recent history (in geological terms). A new peer-reviewed paper by Polissar et al even suggests that the glaciers disappeared completely during the holocene warm period that ended about 5000 years ago (“during most of the past 10,000 yr, glaciers were absent from all but the highest peaks in the Cordillera de Merida.”) Dennis Avery has a summary here. For the more technically minded, Steve McIntyre has a detalied explanation of what this means for the “hockey stick” view that global temperature hasn’t varied much over the past 1000 years here.