Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Where climate is made in a greenhouse world

02.06.2006


New scientific results for the Late Cretaceous greenhouse indicate radically different climatic mechanisms operating about 75-90 million years ago compared to the ones that control today’s climate. The study, published on 29 May 2006 in “Palaeogeography, Palaeoclimatology, Palaeoecology” as part of a special issue on “Causes and Consequence of Marine Organic Carbon Burial Through Time” by Sascha Floegel from the IFM-GEOMAR in Kiel/Germany and Thomas Wagner from the University of Newcastle upon Tyne/UK aims to identify the main ‘climate kitchen’ in a world with about 5-9°C warmer global temperatures than today.



The researchers focus their interest on the causal relationships and feedbacks between the tropics and higher latitudes. Using marine geological records and data from global paleoclimate simulations they identify a previously unrecognized link between higher latitude climate dynamics and tropical African climate, the latter leading to exceptionally high burial of organic carbon in the deep tropical Atlantic. Marine geological record show that enhanced burial of organic carbon in the deep sea was confined to short time envelops of about 5 thousand years that reoccurred over millions of years at a regular pattern (see Beckmann and co-workers, published 8 September 2005 in Nature 437).

Climate modelling is one key technique to identify and understand the larger-scale mechanisms that result in geological evidence. By varying one of Earth’s orbital parameters, the precession of the equinoxes, the modelling setup used in this study provides new insights to the dynamics of global climate during past greenhouse conditions. Accordingly, changes in the amount of energy approaching the top of the atmosphere, called “insolation”, finally triggered cyclic variations of the tropical water cycle in tropical Africa. Periods of enhanced precipitation and freshwater runoff then resulted in massive burial of organic carbon at the sea floor suggesting that processes in the atmosphere drive changes in the ocean. The remaining, fundamental question on the source area(s) where cyclic fluctuations in tropical water cycling and marine carbon burial were triggered was addressed using global climate simulation.


Applying four different orbital configurations of one complete precession cycle the model identifies cross-latitudinal variations of atmospheric pressure systems, fluctuations in the magnitude and direction of surface winds, and associated precipitation and runoff patterns. Previously unrecognized, the model identifies the strongest variations in atmospheric pressure above the South Atlantic at mid-southern latitudes between 25–55°S. Establishment of an atmospheric teleconnection between this area and tropical Africa, however, is limited to one specific orbital configuration, which lasted for about 5 thousand years and caused strongest climate contrasts in a seasonal cycle.

These new results challenge current notions on role of the tropics as main driver of Cretaceous climate. They rather support the conclusion that tropical climate in a greenhouse world is ultimately triggered by climate change at mid-southern latitudes, with precipitation and river discharge being the transport mechanisms.

Today the tropics control a big fraction of Earth’s climate. The new findings reported here suggest that the mid-latitudes will have a much stronger impact on low latitude climate system at predicted future levels of atmospheric CO2. This conclusion has severe consequences for the future low latitude water cycle and associated nutrient and carbon fluxes to coastal areas. The latter fluxes from the continent strongly influence surface ocean productivity, O2 consumption in the water column and thus marine ecosystems, and many other processes affecting the global carbon balance. The broader implications support substantial interaction between the water cycle and atmospheric circulation on regional and hemispheric scales during times of global warmth. As evident from this study we probably still do not realise all the relevant processes that drive future global warming. Knowing them, however, is critical to get prepared and mitigate the effects for society and ecosystems.

Professor Thomas Wagner | alfa
Further information:
http://www.ncl.ac.uk

More articles from Ecology, The Environment and Conservation:

nachricht Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel

nachricht Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

Im Focus: Computer-Designed Customized Regenerative Heart Valves

Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.

Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...

Im Focus: Light-induced superconductivity under high pressure

A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.

Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Supersonic waves may help electronics beat the heat

18.05.2018 | Power and Electrical Engineering

Keeping a Close Eye on Ice Loss

18.05.2018 | Information Technology

CrowdWater: An App for Flood Research

18.05.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>