Nathan J. Steiger

TL;DR: No evidence for preindustrial globally coherent cold and warm epochs is found, indicating that preindustrial forcing was not sufficient to produce globally synchronous extreme temperatures at multidecadal and centennial timescales, and provides strong evidence that anthropogenic global warming is not only unparalleled in terms of absolute temperatures, but also unprecedented in spatial consistency within the context of the past 2,000 years.

TL;DR: In this article, the authors use linear, univariate forward models (PSMs) that map climate variables to proxy measurements by fitting proxy data to 2m air temperature from gridded instrumental temperature data; the linear PSMs are then used to predict proxy values from the prior estimate.

TL;DR: In this article, a review of the principal proxy data available for hydroclimatic reconstructions over the Common Era (CE) and last-millennium model simulations is presented.

TL;DR: In this article, the efficacy of a novel ensemble data assimilation (DA) technique is examined in the climate field reconstruction (CFR) of surface temperature, where a minimalistic, computationally inexpensive DA technique is employed that requires only a static ensemble of climatologically plausible states.

TL;DR: This database, called the Paleo Hydrodynamics Data Assimilation product (PHYDA), will provide a critical new platform for investigating the causes of past climate variability and extremes, while informing interpretations of future hydroclimate projections.