The air contains greenhouse gases such as CO2, which are now known to be responsible for global warming because their concentration has risen continu-ously for a number of years. In contrast to the atmosphere, the concentration of CO2 in the oceans is sixty times higher.
In the global carbon cycle the sea ab-sorbs a proportion of the atmospheric CO2 but also releases CO2 into the at-mosphere again. About half of the anthropogenic emission of CO2 is absorbed naturally by the oceans. Thus it is all the more important to understand how the exchange of CO2 between the ocean and the atmosphere functions with regard to a world that is warming up. The newly available study shows that the ocean was able to store more CO2 during the ice age than it can today.
Practically static bodies of water
Together with North American colleagues, an ETH Zurich research team made measurements on sea bed sediments. These sediments originate from moun-tains lying at a depth of about three kilometres below the water surface of the sub-Arctic Pacific Ocean. At that point the water temperatures are close to freezing and the conditions are very stable, because there is practically no mix-ing between the deep bodies of water and the surface water. The circulation of the water is measured using the radio-carbon method, which is based on the radioactive decay of the carbon isotope 14C. Measurements showed that the deep Pacific water has not been at the surface for more than 2,000 years.
Tiny single-celled organisms betray the CO2 level
To find out how the situation has changed compared to the last ice age, the re-searchers studied mud from the sub-Arctic Pacific Ocean lying approximately one metre below the present sea bed and about 20,000 years old. Tiny single-celled organisms with limestone shells known as foraminifera were selected from this mud under a microscope and afterwards measured with mass spec-trometers. These foraminifers locked in the carbon isotope signature of the seawater of their day - like in a time capsule. The research team has now been able to measure the 14C content precisely. This enabled them to show that the water in the ocean depths exchanged less CO2 with the atmosphere than at present.
A sobering result
The team also looked for key indicators that provide some information about the chemical composition of the ice age water. They found unusually clear evidence that this water captured more CO2 from the atmosphere than the water at the present day. The latest research results show that the oceans are generally able to fix more CO2 when they are cold.
Oceans that warm up as a result of climate change release more CO2 into the atmosphere. This discovery has far-reaching consequences for the climate. The ocean warming caused by humans contributes to the formation of additional greenhouse gases, mainly CO2. Consequently the positive feedback with the atmosphere associated with the latter leads to an even greater acceleration in global warming.
Samuel Jaccard, Research Assistant at ETH Zurich and one of the two principal authors of the study thinks that: "With a system as complex as the climate, even if we cannot draw conclusions directly from the natural cold past that are appli-cable to the warm future modified by humans, our results show that anthropo-genic warming causes additional critical feedback on the CO2 balance."
Original paper: Galbraith, E.D., Jaccard, S.L., Pedersen, T.F., Sigman, D.M., Haug, G.H., Cook, M., Southon, J.R., Francois, R. Carbon dioxide release from the North Pacific abyss during the last deglaciation, Nature, 449, 890-894.
Renata Cosby | idw
Predicting unpredictability: Information theory offers new way to read ice cores
07.12.2016 | Santa Fe Institute
Sea ice hit record lows in November
07.12.2016 | University of Colorado at Boulder
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
07.12.2016 | Health and Medicine
07.12.2016 | Life Sciences
07.12.2016 | Health and Medicine