Data from hundreds of temperature reconstructions show the Northern Hemisphere was significantly warmer for much of the past 10,000 years (Holocene) than it is today. The study published in Climate of the Past examined the sediment records from 66 glaciers and icecaps (GIC) from all over the Arctic, covering the past 12,000 years. Based on these records, they conclude the Arctic was warmer 6,000 years ago than it is today. This research suggests many glaciers and icecaps present today disappeared entirely during the summers 6,000 years ago, as they were warmer than at present. The study reports: "The full Arctic compilation suggests that the majority (50% or more) of studied GICs were smaller than present or absent by ∼10 ka. We find the highest percentage (>90%) of Arctic GICs smaller than present or absent in the middle Holocene at ∼ 7-6 ka, probably reflecting more spatially ubiquitous and consistent summer warmth during this period than in the early Holocene…In the first half of the Holocene, most of the Arctic’s small GICs became significantly reduced or melted away completely in response to summer temperatures that, on average, were only moderately warmer than today."
