Better prediction of climate change
By reconstructing past changes in ocean circulation and climate, paleoceanographer, Nil Irvali, aims to better understand the ongoing changes and improve predictions of our future climate.
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In the deep depths of the basement at the Faculty of Mathematics and Natural Sciences, behind a red door, lies a large and cold room containing sediment cores from the world’s oceans. Underpinning the marine geological research in Norway, samples used to better determine anchoring for ocean wind farms lie side by side with samples that can help us to better predict future climate change.
Thousands of sediment cores are stored in large temperature-controlled room. This core is from south of Greenland.
Almost invisible to the naked eye
Among the many thousands of samples, paleoceanographer at the University of Bergen, Nil Irvali, takes out a core that to the naked eye looks like a column filled with clay. Buried in the sample and almost invisible, lies a wide range of clues Irvali uses to reconstruct the past.
- In this sediment core from the ocean floor of the North Atlantic Ocean, there are tiny microfossils we need a microscope to see. These microfossils are a record of the environment they have lived in, says Irvali.
- By analyzing these microfossils, we can reconstruct sea surface temperatures, measure salinity conditions and how warm it was in the past. This information also helps us to better understand the natural variability of our climate system and gives climate modelers better basis for predicting future, says Irvali.
Laboratory work, and particularly microscoping, is a large part of Irvali’s daily work. When starting on a new project, she easily spends 20-25 hours a week microscoping.
Microfossils are tiny, they are in the range of fine sand grains in size, for example about 0.15 – 0.25 mm in the picture above.
A Microfossil as seen through a scanning electron microscope. This is a planktonic foraminifera called Neogloboquadrina incompta, that lives in the subpolar surface waters.
Mapping recent climate history
Originally from Istanbul, Turkey, it might seem logical for Irvali to explore earthquakes and not sediment cores form the seabed outside Norway. However, an IAESTE summer internship at the Bjerknes Center for Climate Research working with microfossils got her hooked. Today, Irvali works with two strategic projects, under the Centre for Climate Dynamics and the Bjerknes Centre for Climate Research, funded through the Ministry of Education, mainly focusing on the ocean circulation and climate of the last millennium.
In her latest research project, she seeks to combine her passion for microfossils with instrumental records to better understand our recent climate history. Combining the two research methods could help transform our ability to reconstruct and understand climate change, but it has its challenges.
- Working closely with climate modelers has led me to realize how limited our current traditional methods we use to date our samples are. The chronological toolbox we use for dating our sediment cores leads to high age uncertainties, for example up to 50 years with radiocarbon dating, which is still too high if we want to compare our records to short but annually resolved instrumental records, says Irvali.
In addition to extensive work in the lab, Irvali need to go on research cruises to collect sediment cores. Her on a cruise to Greenland last summer.
To narrow down the chronological uncertainties, Irvali propose using anthropogenic signals recorded in the sediments. In her newly published paper, Revising chronological uncertainties in marine archives using global anthropogenic signals: a case study on the oceanic 13C Suess effect, she lays out some of her newest research.
- We are now observing the global effects of anthropogenic activities, such as the increase in atmospheric CO2, also in marine geological archives. I think we might be able to use this information to “date” the very recent marine sediment core material, says Irvali.
- The potential is clear, but there is still a long way to go. Now hard work is needed before a revolution is possible, the impacts need to be painstakingly established so that there are reference curves for different ocean regions and the methods need to be modernized to be more efficient so that sediments can be easily and routinely dated this way.
Although there are some challenges to overcome, if Irvali is successful, her research would provide a better understanding of natural climate variability, extending the instrumental records further back in time with a better precision.