A team of scientists from Cardiff, Bristol and Texas A&M universities braved the lions and hyenas of a small East African village to extract microfossils in samples of rocks which show the level of CO2 in the Earth's atmosphere at the time of the formation of the ice-cap.
Geologists have long speculated that the formation of the Antarctic ice-cap was caused by a gradually diminishing natural greenhouse effect.
The study's findings, published in Nature online, confirm that atmospheric CO2 declined during the Eocene - Oligocene climate transition and that the Antarctic ice sheet began to form when CO2 in the atmosphere reached a tipping point of around 760 parts per million (by volume).
Professor Paul Pearson from Cardiff University's School of Earth and Ocean Sciences, who led the mission to the remote East Africa village of Stakishari said: "About 34 million years ago the Earth experienced a mysterious cooling trend. Glaciers and small ice sheets developed in Antarctica, sea levels fell and temperate forests began to displace tropical-type vegetation in many areas.
"The period, known to geologists as the Eocene - Oligocene transition, culminated in the rapid development of a continental-scale ice sheet on Antarctica, which has been there ever since.
"We therefore set out to establish whether there was a substantial decline in atmospheric carbon dioxide levels as the Antarctic ice sheet began to grow."
The team mapped large expanses of bush and wilderness and pieced together the underlying local rock formations using occasional outcrops of rocks and stream beds.
Eventually they discovered sediments of the right age near a traditional African village called Stakishari. By assembling a drilling rig and extracting hundreds of meters of samples from under the ground they were able to obtain exactly the piece of Earth's history they had been searching for.
Co-author Dr Gavin Foster from the University of Bristol Earth Sciences Department said: "By using the rather unique set of samples from Tanzania and a new analytical technique that I developed, we have, for the first time, been able to reconstruct the concentration of CO2 across the Eocene-Oligocene boundary - the time period about 34 million years ago when ice sheets first started to grow on Eastern Antarctica. "
The new findings offer important lessons for the future and will add to the debate around rising CO2 levels in the earth's atmosphere as the world's attention turns to on UN Climate Conference, which opens in Copenhagen later this year.
Co-author Dr Bridget Wade from Texas A&M University Department of Geology and Geophysics added: "This was the biggest climate switch since the extinction of the dinosaurs 65 million years ago.
"Our study is the first to provide a direct link between the establishment of an ice sheet on Antarctica and atmospheric carbon dioxide levels and therefore confirms the relationship between carbon dioxide levels in the atmosphere and global climate."
Professor Paul Pearson | EurekAlert!
Further reports about: > African elephant > Antarctic Predators > Antarctic ice > Antarctic ice sheet > Antarctica > CO2 > Earth's magnetic field > Eocene > Oligocene > Science TV > atmospheric carbon > atmospheric carbon dioxide > atmospheric carbon dioxide levels > carbon dioxide > carbon dioxide levels > ice sheet
A sudden drop in outdoor temperature increases the risk of respiratory infections
11.01.2017 | University of Gothenburg
Urbanization to convert 300,000 km2 of prime croplands
27.12.2016 | Mercator Research Institute on Global Commons and Climate Change (MCC) gGmbH
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
17.01.2017 | Earth Sciences
17.01.2017 | Materials Sciences
17.01.2017 | Architecture and Construction