Scientists have undertaken an extensive analysis of over 30 years of critical data regarding the thickness of landfast sea ice in Antarctica’s McMurdo Sound, which will assist in assessing future climate change ramifications.
University of Otago — Ōtākou Whakaihu Waka scientists have conducted a thorough analysis of more than three decades’ worth of essential information on the thickness of landfast sea ice in Antarctica’s McMurdo Sound. This research will serve as a valuable tool for evaluating the potential impacts of climate change moving forward.
The findings, published in the Journal of Geophysical Research: Oceans, aimed to uncover the primary factors influencing the thickness of fast ice, analyzing data collected from 1986 to 2022.
Fast ice refers to the frozen sea water that remains attached to coastlines and endures for a minimum of 15 days. It plays a crucial role in providing habitats for penguins and seals, as well as supporting various marine life such as fish, krill, and algae that thrive beneath the ice.
Researchers also navigate the area around McMurdo Sound on the fast ice to conduct experiments and gather data about the oceanic conditions below and the atmospheric conditions above. The thickness and stability of the ice are essential for ensuring safety during these activities.
Instead of indicating a consistent trend of increasing or decreasing thickness, the research highlighted that extreme weather events, ambient air temperatures, and winter wind speeds are the key variables causing yearly fluctuations in fast ice thickness.
Dr. Maren Richter, the leading researcher who completed this work as part of her PhD program at Otago, noted that fast ice in McMurdo Sound has not yet shown pronounced effects from climate change.
“The ocean/ice/atmosphere system in this region still seems capable of counterbalancing the impacts of climate change,” she explained.
“While we do observe a slight rise in air temperatures over the last decade of our study, examining a longer timeline from the mid-1980s onward reveals no clear trend,” she added.
The research data establishes what constitutes ‘normal’ variability for fast ice in McMurdo Sound. This baseline can later be referenced to spot significant changes, such as atypical years or emerging trends in fast ice conditions over successive years.
“The analyzed data underscores the necessity of ongoing and long-term monitoring of the Antarctic environment. Continuous long-term observations allow us to differentiate between natural fluctuations and shifts due to climate change,” she stated.
Dr. Richter intends for the new research to aid modelers in forecasting yearly variations, which would be beneficial for scientists planning ice-based research or for research station operators determining necessary supply ship logistics.
This study may also prove valuable in validating and optimizing models that make projections for decades ahead, helping to assess what average rapid ice conditions might be in 100 years under increased carbon dioxide levels in the atmosphere.
“This might be one of the last opportunities we have to observe certain systems before the impacts of climate change overshadow natural variability,” she remarked.
Co-author and Dr. Richter’s primary PhD supervisor, Associate Professor Inga Smith from the Department of Physics, emphasized that despite the total area of fast ice being considerably less than that of pack ice (fragmented sea ice) in Antarctica, it plays significant roles in Earth’s climate system and is essential for the reproductive success of penguins and seals.
“Our understanding of how fast ice behaves over extended periods is quite limited, which hampers our ability to predict future changes,” she noted.
Dr. Richter pointed out that 30 years of data is still relatively “brief” when discussing climate trends.
“There could have been alterations in earlier years that remain undocumented due to the absence of fast ice thickness measurements at that time.
“I want to emphasize that while no trend has been observed in fast ice thickness in McMurdo Sound, other regions in Antarctica have demonstrated changing trends in fast ice thickness, extent, and duration.”
*Dr. Richter’s PhD research received guidance from Associate Professor Inga Smith, Dr. Greg Leonard from the School of Surveying, and Professor Pat Langhorne from the Department of Physics.
