Research led by a consortium of European researchers has recently examined the link between global climate and erosion rates. Previous studies have suggested that faster erosion rates can be linked to global climate cycles. However, findings from this new study, published in Nature, question this tenuous link.
It has previously been suggested that faster erosion rates can lead to global cooling due to increased silicate weathering, organic carbon burial and, consequently, the removal of CO2 from the atmosphere. Conversely, it has also been suggested that glaciation, and subsequent warming, has led to increased sediment accumulation rates by disturbing terrestrial land which is then carried away in the melt-water.
Thermochronology data tracks how rocks cool as they move toward the surface and has been used recently to analyse mountainous erosion rates over the last few million years – thought to all but confirm the link between erosion rates and glacial-interglacial cycles.
However, a European consortium of researchers, including members from GFZ German Research Centre for Geosciences, University of Potsdam, University of Grenoble and University of Edinburgh, has re-assessed this data. They found that 23 out of 30 locations exhibited apparent increases in erosion due to ‘spatial correlation bias’. This means that spatial variations are converted into temporal variations which could otherwise be explained because the data points were combined across major tectonic faults.
In total, they found 27 out of 30 of the links proposed could be otherwise explained in the context of local data. The other 4 tenuous links, the increases in erosion could be explained by accelerated tectonic deformation, and therefore the faster formation of mountains. The team indicated that thermochronology doesn’t offer the resolution required to assess the effect of climate change on erosion rates. The link will need to be further investigated, incorporating the effect of localised data.
[via phys.org]
