Climate of the Past

How to reconstruct past climates from water stable isotopes in Polar ice cores ?

Mathieu Casado, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany. Anais Orsi, Laboratoire des Sciences du Climat et de l’Environnement, Université Paris-Saclay, France March 15, 2018

Backlit layering in a snow pit in Antarctica (credit waisdivide.unh.edu )

Ice cores are a favored archive to study past climates, because they provide a number of indications on the history of the climate and of the atmospheric composition. Among these, water stable isotopes are considered as a very reliable temperature proxy. Yet, their interpretation is sometimes more complicated than a simple one-to-one correspondence with local temperature and requires intercomparis ...[Read More]

Mountain glacier variations: natural thermometers and rainfall gauges

Pierre-Henri BLARD, CRPG (CNRS, Université de Lorraine), France - Laboratoire de Glaciologie, ULB, Bruxelles, Belgium. February 14, 2018

Glaciers from the Andes Cordillera (Peru, Southern America). Photo credit: Julien Charreau

Name of proxy Fluctuations of mountain glaciers Type of record Geomorphological features Paleoenvironment Continent – High mountain areas Period of time investigated From historical periods (c.a. 300 years ago) to the end of the Pleistocene (up to 200 000 years back in time) How does it work? Mountain – or “alpine” – glaciers are small ice bodies (from 1 to 10 000 km2). Alt ...[Read More]

Varves – Revealing the past layer by layer

Matthew Carney, PhD Student in Physical Geography Manchester Metropolitan University December 22, 2017

Figure 1. Extraction and splitting of glacial lake cores from Chat Moss, Lancashire, U.K.

Name of proxy Varved glacial lake sediments Type of record Sedimentological structures Paleoenvironment Ice marginal lake environments Period of time investigated Last Glacial Termination (LGT, c.21-14 thousands of years (ka)) to present times How do varves work? Proglacial lakes form in front of glaciers and act as sinks for water and sediment flowing from melting ice. Analyses of proglacial lake ...[Read More]

Forams, the sea thermometers of the past!

Mercè Cisneros Bermejo and Cacho Isabel from GRC Geociències Marines, Departament de Dinàmica de la Terra i de l’Oceà, Facultat de Ciències de la Terra, Universitat de Barcelona, Barcelona, Spain November 24, 2017

Figure 1: Planktonic foraminifera Globigerina bulloides specimen (scanning electron microscope picture of Isabel Cacho).

Name of proxy Mg/Ca-SST on planktonic foraminifera shell Type of record Sea Surface Temperature (SST) Paleoenvironment Marine environments Period of time investigated 55 Million years ago to recent times How does it work ? Foraminifera (or Forams) are single-celled organisms varying from less than 1 mm to several cm in size. They are very abundant in the ocean floor (benthic species) or floating a ...[Read More]