Caspar M. Ammann

TL;DR: The Medieval period is found to display warmth that matches or exceeds that of the past decade in some regions, but which falls well below recent levels globally, and the Little Ice Age is marked by a tendency for La Niña–like conditions in the tropical Pacific.

TL;DR: A synthesis of decadally resolved proxy temperature records from poleward of 60°N covering the past 2000 years indicates that a pervasive cooling in progress 2000 years ago continued through the Middle Ages and into the Little Ice Age.

TL;DR: A review of late-Holocene palaeoclimaoclimatology represents the results from a PAGES/CLIVAR Intersection Panel meeting that took place in June 2006 as mentioned in this paper, emphasizing current issues in their use for climate reconstruction; various approaches that have been adopted to combine multiple climate proxy records to provide estimates of past annual-to-decadal timescale Northern Hemisphere surface temperatures and other climate variables, such as large-scale circulation indices; and the forcing histories used in climate model simulations of the past millennium.

TL;DR: This paper extracted volcanic sulfate signals from each ice core record by applying a high-pass loess filter to the time series and examining peaks that exceed twice the 31-year running median absolute deviation.

TL;DR: A significant, multi-year, El Niño-like response to explosive tropical volcanic forcing over the past several centuries is demonstrated, shedding light on how the tropical Pacific ocean–atmosphere system may respond to exogenous radiative forcing.