The South Pole has been warming three times the global average over the past 30 years, study says
The study, published Monday in the journal Nature Climate Change, sheds new light on the most remote region of the Earth. While scientists have known for years that the outer regions of Antarctica are warming, they previously thought that the South Pole, located deep inside, was isolated from rising global temperatures.
“This highlights that global warming is global and is moving to these distant places,” said Kyle Clem, postdoctoral researcher in climate science at the University of Wellington, and lead author of the study.
Clem and his team analyzed data from weather stations at the South Pole, as well as climate models to examine the warming of the interior of Antarctica. They found that between 1989 and 2018, the South Pole had warmed by about 1.8 degrees Celsius over the past 30 years at a rate of + 0.6 ° C per decade – three times the world average.
Scientists have said that the main cause of the warming is the increase in sea surface temperatures thousands of kilometers in the tropics. Over the past 30 years, warming in the western tropical Pacific Ocean – a region close to the equator north of Australia and Papua New Guinea – has led to an increase in the warm air transported to the South Pole.
“It is wild. It is the most distant place on the planet. The importance is to know how the extreme temperatures oscillate and move over the interior of Antarctica, and the mechanisms which drive them are linked 10,000 kilometers (6,200 miles) north of the tropical continent. Pacific, “said Clem.
Melting sea ice, heat waves in Antarctica
While the South Pole remains below freezing and is likely to remain so, Clem said that the warming trend observed at the Pole is related to what we see on the coast and the Antarctic Peninsula.
The warming “starts from the coast and goes inland,” said Clem.
“As you get closer to the coast, where warming is happening, you will start to see more impacts. When you reach this point near the freezing point, you will start to melt. Or you will melt sea ice and warm the ocean in the Weddell Sea and it affects life in this region, “he said.
Is the climate crisis to blame?
Initially, scientists discovered that the South Pole cooled by more than a degree during the 1970s and 1980s, as global temperatures increased. The team said the cool period was due to natural climate patterns that occur in cycles of 20 to 30 years.
Then the trend quickly reversed “and all of a sudden we have almost 2 degrees of warming at the turn of the century,” said Clem.
The jump from one degree of cooling to 2 degrees of warming meant an increase of 3 degrees.
Meanwhile, global temperatures have risen by about 1 degree Celsius (1.8 degrees Fahrenheit) above pre-industrial levels and the goal is to keep global median temperatures below 1.5 degrees Celsius (2, 7 degrees Fahrenheit) to avoid the worst impacts of the climate crisis.
Clem said the extreme fluctuation of the South Pole suggests that natural variability “masks” the effects of human-induced climate change.
The team discovered that the warming was caused by natural variations in sea surface temperatures over several decades. But these natural climatic factors “acted in tandem” with or were reinforced by global emissions of greenhouse gases.
“We have natural processes that will always occur in the midst of global warming and human influence on the climate system,” said Clem. “When the two work together, it’s pretty remarkable.”
The science behind global warming
In addition to human interference from greenhouse gas emissions, the researchers said that several natural processes work behind the scenes to warm the South Pole.
A climatic phenomenon called the Pacific Interdecadal Oscillation (IPO), which governs ocean temperatures in the Pacific Ocean, went from a positive phase to a negative phase at the turn of the 21st century. This warmed the western tropical Pacific and caused more intense cyclones and storms.
All of this has made the South Pole one of the hottest places on the planet.
Upper limits of natural variability
Because temperature readings from the South Pole only date back to 1957, scientists could not draw a definitive conclusion that the warming was due to human activity.
They therefore used models that simulate the Earth’s climate with concentrations of greenhouse gases representative of pre-industrial times – therefore without human influence.
In the simulations, the team calculated all possible trends over 30 years that could occur at the South Pole in these models. They found that the observed warming of 1.8 C was greater than 99.9% of all possible trends over 30 years that occur without human influence.
The authors stated that, if this meant that the warming “was within the upper limits of the simulated range of natural variability”, the nature of the trend was “remarkable”.
“Almost everywhere else on Earth, if you had 1.8 ° C of warming over 30 years, it would be off the charts.” Said Clem.
But the result was not 100%. So according to Clem, it is possible that the warming of the South Pole occurred only through natural processes. but it’s tiny.