The study reveals the uncertainties arising from the effects of climate change.
A study co-lead by the CIIMAR researcher Irina Gorodetskaya, brings together all up-to-date data on the phenomenon of atmospheric rivers in Antarctica and reveals the uncertainties arising from the effects of climate change.
Atmospheric rivers are long, narrow corridors of intense horizontal moisture transport in the atmosphere that carry both moisture and heat from the tropics to the poles. They are a relatively new climatic phenomenon in the field of meteorology and climate and their understanding has changed a lot over the last 10 years.
A review study by an international community of researchers from ten countries, co-lead by CIIMAR researcher Irina Gorodetskaya together withJonathan Wille (ETH, Switzerland) and Vincent Favier (IGE, France), brought together all the information on the phenomenon of atmospheric rivers available over the last 10 years of research. The article “Atmospheric rivers in Antarctica” is now published in the journal Nature Reviews Earth & Environment.
An emerging area
By their very nature, atmospheric rivers strongly affect humidity levels, precipitation and temperature in polar regions. Antarctica, the great frozen continent that holds more than 90% of the world’s fresh surface water, is no exception. The last 10 years of research into this climatic phenomenon show us that, although atmospheric rivers appear to have a positive effect on the ice sheet balance by promoting snowfall, they can also cause melting and instability in the Antarctic ice sheets and thus contribute to the Antarctic ice sheet mass loss and its contribution to the global sea level rise .
The fact is that Antarctica has been losing mass at an exponential rate since 1992, with losses reaching 150 billion tons of ice per year. “In this context, atmospheric rivers have been responsible both for compensating for these losses by causing large snowfall events, and for exacerbating this loss of mass by inducing more melting events and instability,” explains Irina Gorodetskaya, a researcher at CIIMAR.
The knowledge gathered
It has become clear over the last 10 years that atmospheric rivers are extremely important for modeling the Antarctic climate. The study “Atmospheric rivers in Antarctica”, highlights the preponderant role of atmospheric rivers in the Antarctic region and provides information on their drivers as well as their impacts on the Antarctic climate and mass balance.
According to Irina, “among the main processes described in this review study are dynamic atmospheric patterns specific to this region and which seem to influence both the formation of atmospheric rivers and their direction towards Antarctica, in addition to the impact of tropical convection and local meteorological phenomena such as the Foehn winds”.
What does the future hold?
Climate change will probably cause stronger atmospheric rivers as global warming increases atmospheric water vapor. Although the current large-scale snowfall caused by atmospheric rivers helps Antarctica gain some mass, they also produce losses through the melting and destabilization of ice shelves. From the point of view of the CIIMAR researcher, “the final impact is difficult to assess and predict due to a series of non-linear effects. What we have learned from recent research is that, although the contribution of melting caused by atmospheric rivers to the total balance of the Antarctic mass is currently small, it could become significant because of global warming.”
Irina also stresses the importance of research in better understanding these effects: “these uncertainties and questions require continued observation and modeling efforts to understand how atmospheric rivers will evolve in a changing climate.” Understanding the relationship between atmospheric rivers in Antarctica and the ice mass balance is crucial to reducing uncertainty in future climate projections, including impact of Antarctica on sea level rise across the globe.
Photo by Irina Gorodetskaya. Low clouds and icebergs near the Antarctic Peninsula. Atmospheric rivers bring clouds and increased snowfall but can also cause rainfall, surface melt and ice shelf disintegration.
