Sediments deposited in oceans by major Arctic rivers hold clues to future global climate

May 19th, 2009 - 2:08 pm ICT by ANI  

Washington, May 19 (ANI): A new study has suggested that sediments deposited in the ocean by major Arctic rivers may hold clues to understand how Earth’s climate will change in the next few decades.

The study was carried out by geoscientists at The University of Texas at Austin and Texas A and M University, US.

Sediments deposited in large river deltas around the world record information about past sea level, productivity and storminess on the ocean margin, climate on the adjacent continents and human factors that affect sediment delivery to the margin, among other things.

In addition to these climate factors, Arctic sediments, in particular, could contain records of changes on land due to warming, including permafrost temperature and melting of upland glaciers.

According to Mead Allison, senior research scientist at The University of Texas at Austin’s Jackson School of Geosciences and co-author of the study, Arctic river deltas have been neglected as records of past climate because the far north is a challenging and expensive environment to work in and it only came to be seen as a bellwether for climate change in the last decade or so.

Arctic river deltas are critical to explore because the largest changes in climate are projected for the Arctic, said the researchers.

Large amounts of carbon are stored in Arctic permafrost. As those soils thaw, rivers will transport much of their organic carbon to the oceans.

As global warming speeds up the melting of shorefast ice (ice attached to the shore), it will likely accelerate coastal erosion from storms, providing a further supply of organic carbon to the coastal zone.

Allison described several ways these sediments could advance scientists’ understanding of the global climate system.

They could help answer a hotly debated question about the role of river deltas in the global carbon cycle.

Arctic river deposits could also confirm the existence of natural climate cycles that climate models need to take into account.

Finally, these sediments would establish past climate proxies for specific locations that could be monitored in the future to track the changing climate of the Arctic.

If it is a region that will experience the biggest climate changes in this century, it will be important to establish how climate is recorded in sediments. (ANI)

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