A paper was recently published entitled ‘Antarctic extreme seasons under 20th and 21st century climate change’. The paper provides the first overview of the evolution of extreme seasons over Antarctica and the Southern Ocean during the 20th and 21st centuries.
Many of the major impacts of climate change are associated with changing intensity and frequency of weather extremes. Vulnerable ice shelves are at most risk of collapse during extreme conditions, with consequences for global sea level. Unique ecosystems can come under greatest strain during extreme conditions. For example when rain falls instead of snow penguin breeding can be severely affected.

A cool rainy day may not seem like an extreme weather event to us in the UK. However, in Antarctica, a continent of ice and snow, a rainy day is an extreme weather event with potentially catastrophic impacts for delicately balanced physical and biological systems. Indeed extreme weather and climate events, whereby conditions differ considerably from normal for a given location, are key to understanding many aspects of how climate change could affect, and is affecting, Antarctica and the planet. Occasions when extreme conditions persist over a sustained period, such as a season, are of particular relevance to impacts as they can produce accumulated effects of greater impact than a single weather event. For example, the breakup of ice shelves and subsequent impacts on global sea level or severe impacts on penguin breeding.
New research just published has provided the clearest picture yet of how extreme seasons may change, and are changing, in a warming world. The work used state-of-the art climate model simulations to build a comprehensive picture of changing seasonal extremes in temperature, precipitation and wind. A key overall message is that changes in extreme seasons do not in general follow change in background climate. The characteristics of these differences vary considerably across temperature, precipitation and wind and between summer and winter. A key implication is that we cannot, for example, assume that the severity of extreme melt seasons over ice shelves will follow background mean conditions.
More specifically, the research shows that the regional picture of changing temperature extremes is, at many key locations, strongly controlled by changes in sea ice. Possibly of greatest relevance to the global climate system is that poleward-shifting storm tracks in austral summer reduce the range in seasonal wind extremes over large parts of the Southern Ocean, where wind variability is thought to be an important driver of variability in the Southern Ocean carbon sink.
This research sets the stage for further detailed quantitative studies of the impacts of changing Antarctic extremes and their local and global impacts. In particular two major UKRI-funded projects are now underway to address these very issues. These are ExtAnt, led by BAA, and PICANTE, which includes significant BAS involvement.
Read the full article here.
Article written by Thomas Bracegirdle