The study, published in the Journal of Geophysical Research: Oceans, examined fast ice conditions from 1986 to 2022. Fast ice, which forms when ocean water freezes and remains attached to land, is an essential habitat for various species, including penguins, seals, and marine life such as krill and algae. Additionally, it offers a stable platform for scientific research, as scientists traverse the ice to monitor both the ocean beneath and the atmosphere above.
Contrary to expectations of a consistent decline in ice thickness due to climate change, the researchers discovered that fast ice thickness in McMurdo Sound varies year-to-year, mainly influenced by storm events, air temperatures, and wind speeds. There was no clear long-term trend suggesting significant impacts from climate change during the study period.
Lead researcher Dr. Maren Richter, who conducted the study as part of her PhD at Otago, stated, "The ocean/ice/atmosphere system there seems to still be able to balance out effects of climate change." She added, "We see a slight increase in air temperatures over the last 10 years of our study period, but if we look at air temperature over a longer time period (from the mid-1980s to now) there is no clear trend."
The findings provide a baseline for understanding natural variability in ice thickness, which can be used to detect when significant changes occur, such as shifts in ice conditions that could signal the early effects of climate change. Dr. Richter emphasized the importance of long-term monitoring, saying, "Only long time series of observations allow us to distinguish between natural variability and trends influenced by climate change."
The data from this research will be instrumental for modeling future ice thickness variations, helping scientists predict conditions for upcoming years. It could also guide research planning in Antarctica and assist logistics teams in choosing the appropriate vessels for station resupply operations.
The study could also serve as a reference for future models projecting changes over the coming decades, particularly with rising carbon dioxide levels in the atmosphere. Dr. Richter concluded, "Now might be the last time we can observe some systems before effects of climate change dominate over natural variability."
Co-author Dr. Inga Smith, Richter's PhD supervisor and Associate Professor at Otago's Department of Physics, noted that while fast ice covers a smaller area than pack ice, it plays a critical role in the Earth's climate system and the survival of species like penguins and seals. "We know very little about how fast ice behaves over long periods of time which means we cannot currently predict future changes," she explained.
Dr. Richter pointed out that 30 years of observations are still relatively short when it comes to detecting climate trends. "There might have been changes in earlier years which we do not know about because we were not measuring fast ice thickness," she said. Despite no discernible trend in McMurdo Sound, she cautioned that other regions in Antarctica have shown notable changes in fast ice characteristics.
The full study, titled The Interannual Variability of Antarctic Fast-Ice Thickness in McMurdo Sound and Connections to Climate, is available for further reading here: [DOI link](http://dx.doi.org/10.1029/2023JC020134).
Dr. Richter's research was supported by funding from the University of Otago, Antarctica New Zealand, NIWA, the Antarctic Science Platform, Te Punaha Matatini, and the Royal Society of New Zealand.
Related Links
University of Otago
Beyond the Ice Age
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