Arctic River Deltas May Hold Important Climate Information
28.05.2009 - Water & Oceans, Land & Geology, Other, Arctic
A new study suggests that scientists struggling to understand how Earth's climate will change in the next few decades could find useful information in sediments deposited in the ocean by major Arctic rivers. 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.
Mead Allison, senior research scientist at The University of Texas at Austin's Jackson School of Geosciences and co-author of the study, described several ways these sediments could advance scientists understanding of the global climate system.
- They could help answer a hot topic concerning the role of river deltas in the global carbon cycle. Scientists don't know whether large river deltas are a net source or a net sink of carbon. That's a critical question because carbon dioxide is a major greenhouse gas and because human acivity alters river systems in many ways (damming, diverting, etc.), potentially shifting the ability of those systems to fix, burn and store carbon.
- Arctic river deposits could also confirm the existence of long natural climate cycles that climate models need to take into account. Because there are only about 50 years of high quality climate data from the Arctic, it is sometimes hard to assess to what extent changes now being observed are natural or human-induced. River delta sediments might allow scientists to reconstruct Arctic climate for thousands of years into the past, giving scientists a better insight into long natural cycles.
- 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.
- Another advantage of studying margin sediments adjacent to large rivers in the Arctic and elsewhere is that they are deposited at a very high rate. This makes it possible to extract information on a year-to-year basis with high resolution.
