Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

What does global climate have to do with erosion rates? Not so much, say scientists

05.07.2018

For the last several decades, Geoscientists have been intrigued by a potential link between erosion rates at the Earth’s surface and changes in global climate. What was the cause and what the effect remained unclear. However, a new study now calls into question the link itself. A team of researchers re-examined 30 locations with reported accelerated erosion after the onset of glacial-interglacial cycles a few million years ago. In nearly all of the locations, the proposed link between erosion and global climate could not be confirmed. Their study appears in the current issue of Nature.

The basic ideas sound convincing: Faster erosion rates can lead to faster silicate weathering and efficient burial of organic carbon in sedimentary basins, both of which can induce global cooling by removing CO2 from the atmosphere.


The U-shaped Veneon Valley was formed by glaciers and erosion.

Taylor Schildgen/GFZ

On the other hand, a global increase in erosion rates over the last several million years was associated with glacial-interglacial cycles. This was proposed on the basis of accelerated worldwide sedimentation rates in the oceans. Glaciers scraping off landscapes and subsequent warmings that lead to meltwater transporting sediment into the sea are plausible causes for increased sediment-accumulation rates.

Yet, other studies have indicated that global erosion rates may have remained steady over this time period, and that the apparent increased sediment-accumulation rates are due to the irregularities in how sediments are deposited in space and time, and because older deposits are more likely to be lost by erosion compared to younger deposits.”

More recently, a global compilation of thermochronology data, which tracks the cooling history of rocks as they move toward the surface, has been used to infer a nearly two-fold erosion-rate increase from mountainous landscapes over the last several million years.

So the link between glacial-interglacial cycles and faster erosion seemed to be confirmed – until a team of researchers from the GFZ, led by Taylor Schildgen, and from the Universities of Potsdam, Grenoble, and Edinburgh re-examined the 30 locations with reported accelerated erosion based on thermochronology.

Their analysis shows that in 23 of these locations, the reported increases are a result of what they term a “spatial correlation bias”; i.e., combining data with disparate cooling histories, a process that converts spatial variations in erosion rates into temporal increases.

In most cases, the disparate cooling histories result because data points were combined across major tectonic boundaries (faults). In four other locations, the increases can be explained by accelerated tectonic deformation (i.e., faster mountain-building processes), rather than climatic changes.

Together, these 27 erroneous out of 30 proposed links between faster erosion and climate can be explained by neglecting the local context of the data in the earlier analysis, a dangerous potential pitfall in big-data analysis. In only three cases, climatically induced accelerations are recorded, driven by localized glacial-valley incision.

The team’s findings suggest that thermochronology data currently have insufficient resolution to assess if climate change over the last several millions years affected erosion rates on a global scale. They conclude that currently, no data provide clear support for the hypothesized link between faster erosion and global cooling. Nonetheless, a synthesis of local findings that include location-specific information may help to further investigate drivers of global cooling and erosion rates.

Original study: Spatial correlation bias in late-Cenozoic erosion histories derived from thermochronology

Weitere Informationen:

https://www.nature.com/articles/s41586-018-0260-6 - Link to the paper (you'll need an account with Nature or a subscription)

Josef Zens | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ
Further information:
http://www.gfz-potsdam.de/

More articles from Earth Sciences:

nachricht Turbulence creates ice in clouds
08.11.2019 | Leibniz-Institut für Troposphärenforschung e. V.

nachricht Manganese nodules: project on environmental impact during deep sea mining
08.11.2019 | Jacobs University Bremen gGmbH

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A new quantum data classification protocol brings us nearer to a future 'quantum internet'

The algorithm represents a first step in the automated learning of quantum information networks

Quantum-based communication and computation technologies promise unprecedented applications, such as unconditionally secure communications, ultra-precise...

Im Focus: Distorted Atoms

In two experiments performed at the free-electron laser FLASH in Hamburg a cooperation led by physicists from the Heidelberg Max Planck Institute for Nuclear physics (MPIK) demonstrated strongly-driven nonlinear interaction of ultrashort extreme-ultraviolet (XUV) laser pulses with atoms and ions. The powerful excitation of an electron pair in helium was found to compete with the ultrafast decay, which temporarily may even lead to population inversion. Resonant transitions in doubly charged neon ions were shifted in energy, and observed by XUV-XUV pump-probe transient absorption spectroscopy.

An international team led by physicists from the MPIK reports on new results for efficient two-electron excitations in helium driven by strong and ultrashort...

Im Focus: A Memory Effect at Single-Atom Level

An international research group has observed new quantum properties on an artificial giant atom and has now published its results in the high-ranking journal Nature Physics. The quantum system under investigation apparently has a memory - a new finding that could be used to build a quantum computer.

The research group, consisting of German, Swedish and Indian scientists, has investigated an artificial quantum system and found new properties.

Im Focus: Shedding new light on the charging of lithium-ion batteries

Exposing cathodes to light decreases charge time by a factor of two in lithium-ion batteries.

Researchers at the U.S. Department of Energy's (DOE) Argonne National Laboratory have reported a new mechanism to speed up the charging of lithium-ion...

Im Focus: Visible light and nanoparticle catalysts produce desirable bioactive molecules

Simple photochemical method takes advantage of quantum mechanics

Northwestern University chemists have used visible light and extremely tiny nanoparticles to quickly and simply make molecules that are of the same class as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

High entropy alloys for hot turbines and tireless metal-forming presses

05.11.2019 | Event News

Smart lasers open up new applications and are the “tool of choice” in digitalization

30.10.2019 | Event News

International Symposium on Functional Materials for Electrolysis, Fuel Cells and Metal-Air Batteries

02.10.2019 | Event News

 
Latest News

How the Zika virus can spread

11.11.2019 | Life Sciences

Researchers find new potential approach to type 2 diabetes treatment

11.11.2019 | Health and Medicine

Medica 2019: Arteriosclerosis - new technologies help to find proper catheters and location of vasoconstriction

11.11.2019 | Trade Fair News

VideoLinks
Science & Research
Overview of more VideoLinks >>>