Pliocene Warmth, Polar Amplification, and Stepped Pleistocene Cooling Recorded in NE Arctic Russia

Abstract

Understanding the evolution of Arctic polar climate from the protracted warmth of the middle Pliocene into the earliest glacial cycles in the Northern Hemisphere has been hindered by the lack of continuous, highly resolved Arctic time series. Evidence from Lake El'gygytgyn, in northeast (NE) Arctic Russia, shows that 3.6 to 3.4 million years ago, summer temperatures were ~8°C warmer than today, when the partial pressure of CO2 was ~400 parts per million. Multiproxy evidence suggests extreme warmth and polar amplification during the middle Pliocene, sudden stepped cooling events during the Pliocene-Pleistocene transition, and warmer than present Arctic summers until ~2.2 million years ago, after the onset of Northern Hemispheric glaciation. Our data are consistent with sea-level records and other proxies indicating that Arctic cooling was insufficient to support large-scale ice sheets until the early Pleistocene.

Late Pliocene and Early Pleistocene vegetation history of northeastern Russian Arctic inferred from the Lake El'gygytgyn pollen record

“…Building on the initial studies of Melles et al (2012) and Brigham-Grette et al (2013), this paper provides a more complete record and a more detailed discussion of climatical and environmentally driven vegetation changes in the northeastern Russian Arctic between ∼ 3.58 and ∼ 2.15 Myr BP. Their papers are based on the original work presented here.…”

“…A first compilation of data obtained from the lower part of the Lake El'gygytgyn sediment record, from ∼ 3.6 to ∼ 2.2 Myr BP, was provided by Brigham-Grette et al (2013). In this study multiproxy evidence suggests extreme warmth and polar amplification during the middle Pliocene, ∼ 3.6 and ∼ 3.4 Myr BP, when temperatures were ∼ 8 • C higher but pCO 2 is estimated at ∼ 400 ppm, comparable with today.…”

Stratigraphic and Paleoenvironmental Reconstruction of a Mid-Pliocene Fossil Site in the High Arctic (Ellesmere Island, Nunavut): Evidence of an Ancient Peatland with Beaver Activity + Online Appendix Figures S1 and S2 (See Article Tools)

“…Climate estimates from the Beaver Pond site and the nearby Fyles Leaf Bed site, using multiple proxies, show evidence of a climate Mean Annual Temperature (MAT) that was 14˚ to 22˚C warmer than today (Table 1). The Beaver Pond site and other sites, including the recently described Lake El'gygytgyn record (NE Arctic Russia) (Brigham-Grette et al, 2013), offer key evidence for understanding the history of the Arctic terrestrial climate in the context of global warming. Despite the importance of the Beaver Pond site in paleoecological and paleoclimate research, the sedimentology and depositional history of the site have not been characterized.…”

Drilling the solid earth: global geodynamic cycles and earth evolution

“…This is important because drilling is expensive, and projects that can address multiple themes will win wider support and result in more scientific impact, than projects that are limited to a single issue or theme. Examples of the synergy that results from successful projects with multiple themes include lake-drilling projects that address both climate change and impact processes (Brigham-Grette et al 2013) and projects that address volcanic processes and geothermal energy (Shervais et al 2013a) or magmatic processes and ore formation.…”