CL
Climate: Past, Present & Future

past climate reconstruction

Misinterpretation of glacial aridity in subtropical environments in the Southern Hemisphere

and March 11, 2024
Misinterpretation of glacial aridity in subtropical environments in the Southern Hemisphere

To understand Earth’s changing climate, scientists often examine how the climate has varied in the past, by studying geological records. These records allow us to reconstruct past climates and help us predict planet’s responses to different climate forcings. In this context, it has long been thought that past ice ages on Earth were relatively dry, whereas the warm periods between ice ages we ...[Read More]

Levoglucosan, the witness of past fires

June 6, 2018
Levoglucosan, the witness of past fires

Name of proxy Levoglucosan Type of record Biomass burning Paleoenvironment Lake and marine sediments and ice cores Period of time investigated Present to approximately 130,000 years ago How does it work? Levoglucosan is a molecule that is exclusively formed during the combustion of vegetation at low-temperature. It is therefore considered to be a source-specific tracer for biomass burning. During ...[Read More]

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

March 15, 2018
How to reconstruct past climates from water stable isotopes in Polar ice cores ?

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

February 14, 2018
Mountain glacier variations: natural thermometers and rainfall gauges

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]

Forams, the sea thermometers of the past!

and November 24, 2017
Forams, the sea thermometers of the past!

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]

What speleothems can tell about the past climates !

and September 5, 2017
What speleothems can tell about the past climates !

Name of the proxy: Stable isotope ratios of carbonates in speleothems Type of proxy: Precipitation, atmospheric circulation, CO2 availability in soil, soil productivity Paleoenvironment: Continental environments Period of time investigated: Present day to 10 million years How does it work? Speleothems are inorganic carbonate deposits growing in caves that form from super-saturated cave waters (wit ...[Read More]