Climate change is accelerating in Antarctica

By | March 19, 2024

In recent years, Antarctica has experienced a series of unprecedented heat waves. On February 6, 2020, temperatures of 18.3 degrees Celsius were recorded, the highest ever on the continent, surpassing the previous record of 17.5 degrees Celsius, set only a few years earlier.

Around February 2022, another strong heat wave in Antarctica led to a record-breaking melt of surface ice. In March of the same year, East Antarctica experienced its strongest heat wave on record, with temperatures rising to 30°C or 40°C above average in some areas.

This past year has seen the lowest levels of Antarctic sea ice cover since records began.

Record-breaking temperatures during the heat wave on February 6, 2020. González-Herrero et al. (2022)

Record-breaking temperatures during the heat wave on February 6, 2020. González-Herrero et al. (2022)

The events of recent years border on the unbelievable, and it is difficult not to connect them to climate change. In fact, studies have already emerged that clearly attribute some of these heat waves to global warming: one of our studies strongly suggests that without the influence of climate change, the record temperatures of 2020 would not have happened.


Read more: A heat wave in Antarctica has completely rocked scientists’ minds. They set out to decipher it – and here are the results


Antarctica’s changing climate

In 2009, a study quantified the rate of ecosystem migration due to climate change on a global scale, essentially documenting the speed at which certain species must move to ensure their survival. It concluded that biomes moved at a speed between 0.8 and 12.6 km per decade, with an average speed of 4.2 km per decade.

In our more recent study, published in February 2024, we adapted this velocity measurement and applied it to the margins of Antarctica. To do this, we followed the southward migration of the zero degree isotherm.

The zero degree isotherm is an imaginary line that encloses the areas that are at zero degrees or lower. The southward movement means that the area of ​​sub-zero Celsius temperatures in Antarctica is shrinking. Since water freezes at zero degrees, this movement will have serious consequences for ecosystems and for the cryosphere (areas on Earth where water is frozen).

Our calculations show that the zero-degree isotherm has been moving at a rate of 15.8 km per decade in the Antarctic region since 1957, while on the Antarctic Peninsula itself it is moving at a rate of 23.9 km per decade has moved. As a result, it now lies more than 100 km south of where it was in the mid-20th century.

These measurements show that the rate of climate change on the edge of Antarctica is four times faster than the average for other ecosystems.

Evolution of the annual and seasonal position of the zero degree isotherm in Antarctica between 1957 and 2020. The initials indicate the seasons for each measurement.  MAM: autumn, JJA: winter, SON: spring, DJF: summer.  González-Herrero et al. (2024)Evolution of the annual and seasonal position of the zero degree isotherm in Antarctica between 1957 and 2020. The initials indicate the seasons for each measurement.  MAM: autumn, JJA: winter, SON: spring, DJF: summer.  González-Herrero et al. (2024)

Evolution of the annual and seasonal position of the zero degree isotherm in Antarctica between 1957 and 2020. The initials indicate the seasons for each measurement. MAM: autumn, JJA: winter, SON: spring, DJF: summer. González-Herrero et al. (2024)

The consequences of emissions

To predict the consequences of the southward migration of the zero degree isotherm, we ran our data through twenty different climate models. While there is some variation in the isotherm’s shift among the models, they all agree that it will move significantly further south in the coming decades.

The models also predict that the isotherm’s movement will accelerate in the coming decades, regardless of emissions. However, the extent of the southward movement in the second half of the 21st century will depend on the amount of carbon we emit.

If we continue at the current rate of emissions, the zero degree isotherm will continue to develop at a similar rate before slowing down in the second half of the 21st century. However, if emissions are higher, the isotherm migration will accelerate the southward movement until the end of the century.

Change in the summer position of the zero degree isotherm over the course of the 21st century.  Based on IPCC climate scenario SSP5-8.5, with current emission levels approximately doubling by 2050. <a href=Adapted by González-Herrero et al. (2024)” data-src=”https://s.yimg.com/ny/api/res/1.2/zOxaxjYP6Tyf9qd0_1TfOg–/YXBwaWQ9aGlnaGxhbmRlcjt3PTk2MDtoPTc1NQ–/https://media.zenfs.com/en/the_conversation_en_espa_ol/d2b1f4af2afdd0 0113950a5bf3381e48″/>Change in the summer position of the zero degree isotherm over the course of the 21st century.  Based on IPCC climate scenario SSP5-8.5, with current emission levels approximately doubling by 2050. <a href=

Impact on the cryosphere and ecosystems

The southward movement of the zero degree isotherm will not only remain in the atmosphere, but will also affect the cryosphere (all frozen areas of Antarctica) and the biosphere (the species that live there).

Changes in the position of the isotherm will lead to more liquid rain instead of snow in the outermost regions of the continent, although this may actually lead to more snowfall in other areas.

Less snowfall on the frozen sea – which acts as insulation – could lead to accelerated sea ice loss during summer thaws.

Although the effects on permafrost, ice shelves and continental ice are still uncertain, this will undoubtedly affect the peripheral glaciers of the Antarctic Peninsula. These represent one of the largest potential sources of sea level rise in the coming decades.

Changes in the cryosphere will also lead to changes in ecosystems. New areas will become habitable thanks to the thawing ice, but with more areas above zero degrees, invasive species from warmer, more hospitable continents may be able to establish themselves, competing with native species for resources.

This article was originally published in The Conversation, a post dedicated to comparing ideas from academic experts.

Lee mas:

Sergi González has not received any salary, has not done any consultancy work, has not done any acciones, has not received any funding from any company or organization that could benefit this article, and he has declared that he has provided care to relevant relevant cases throughout the academic world.

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