Antarctica turns green, what implications does it have? Spanish scientists respond

10/28/2024

Updated at 8:45 p.m.

“Autumn arrives in Antarctica and with it, we return home,” notes Asunción de los Ríos, researcher in the Microbial Ecology and Geomicrobiology Group of the National Museum of Natural Sciences (MNCN-CSIC). Thus he closes his logbook and thus puts an end to his four weeks on the Hurd Peninsula.

There are no regular flights or ferries that arrive there. In fact, few ships do it and one of them is the Hespérides of the Spanish Armed Forces. The map coordinates read 62°40′33″S 60°21′59″W. With the arrival of the autumn equinox, the days become shorter in this area of ​​the planet. “It is time to return home and leave Livingston Island and the Juan Carlos I Spanish Antarctic Base, where we have been so well and the last month has been so scientifically productive,” de los Ríos’ travel diary closes.

These words were written in March 2024. Hours later, he turned off his computer, closed his backpack and headed to Spain. Behind was the coastline where the white ice and snow give color to a unique postcard. “Here you see the greatness of nature and how small we humans are,” he explains. Elisa Berdalet, marine biologist at the Institute of Marine Sciences and researcher at the CSIC. “You can also see, despite our smallness, all the damage we do to this giant,” he adds.

A wound that is also reflected in the logbook of Asunción de los Ríos. Is Livingston Island turning green?, digital daily plasma. «At least in some areas we would say yes. It seems that we are in the north of Spain, instead of in Antarctica,” he adds. “My first expedition to the South Shetlands was in 2014,” he tells this newspaper by phone. «Yes, changes have been seen since then and the most striking is the retreat of the glaciers. For years, the soils that we now see in front of the glaciers have been covered with ice and with its recent thaw a pioneering colonization led by microorganisms has begun, which is followed by the establishment of mosses and plants,” he explains.

According to satellite data obtained between 1986 and 2021, they confirm that vegetation is gradually making its way between the rocks of the frozen continent. In those three decades of observation, the green has gone from one square kilometer to almost 12. “There are mosses, lichens and I have also seen some grasses,” remembers Bardelet. “These effects are especially visible in maritime Antarctica,” clarifies Asunción de los Ríos. “On the continental shelf it does increase, but the loss on the peninsula already has effects on life on the planet,” he adds. Maria Vila-Costa, researcher at IDAEA-CSIC.

Some of them are known, others are yet to be discovered. “Our research focuses on contaminants and it is worrying because we have found them in the Antarctic snow and ice and there is no factory there,” warns Vila-Costa. Based on their findings and those of other colleagues in the sector, it is known that Antarctica absorbs and captures these substances. “We have found hydrocarbon particles, as well as the aromatic substances they contain, flame retardants, gore-tex…”, he lists. “They are all ‘trapped’ in Antarctica, but if it thaws, what will happen?” he asks. “We know that moss is also another source that allows them to be trapped and that is what we continue to investigate.”

Green, do I love you green?

The acceleration in the advance of vegetation in Antarctica represents a challenge for the scientific community, which seeks to better understand the processes that are transforming this landscape. Asunción de los Ríos has been monitoring the slow but continuous advance of the ‘Antarctic green’ for years and now, together with Rebeca Arias del Real, is analyzing the effects of ephemeral currents caused by glacial melt on this advance.

With their eyes they have seen how the glaciers retreat and the soils and volcanic rocks of their moraines are exposed to be colonized. “There is a great diversity of microorganisms in Antarctica that we still do not know,” he details. Using molecular biology and electron microscopy techniques, it analyzes each of the samples taken in, perhaps, the most inhospitable area on the planet. “The temperatures are very low and there are very strong winds, but it is worth it,” he says. “You arrive at a place where you think there is nothing, you hit with the hammer, you collect samples, you return to Spain, you put it under the microscope and you find that they are colonized by microorganisms,” says de los Ríos. But the most worrying thing about their findings is that many of these species, so well adapted to surviving in cold latitudes, could disappear with the expected changes in temperature, as has happened previously.

This is how they have verified it María Ángeles Bárcena and Andres Rigual. Both are researchers at the University of Salamanca and their work focuses on investigating the secrets that sediments keep. Their microscopes and training allow them to ‘read’ records from millions of years ago that were recorded in fossils, rocks and ice.

It seems that 140 million years ago, our planet experienced one of the warmest times in history. This happened around the middle of the Cretaceous period, about 90 million years ago. Bárcena and Rigual have been able to ‘travel’ in time to about 20,000 years ago, in their case, in the Arctic. “The sediments tell us that there was more ice coverage on the Svalbard islands,” reveals Rigual. “I have been this summer and I have not seen ice,” adds Bárcena.

Both poles are melting drop by drop, little by little. This year, Antarctic sea ice extent reached its annual maximum extent of 17.2 million square kilometers (km2) on September 19. This is the second lowest value in a satellite record going back 46 years, and 1.6 million km2 less than the average maximum from 1981-2010, notes the US National Snow and Ice Data Center ( NSIDC). Meanwhile, at the other pole of the Earth, the Arctic reached its minimum summer extent on September 11, ranking as the seventh lowest on record, according to this organization.

This poses two problems. “One is the rise in sea level, because we must remember that Antarctica hosts 80% of the planet’s fresh water,” explains Amanda del Río. And the other is “the alteration of the ocean currents that regulate the planet’s temperature,” adds Bárcena. “This is more worrying because the melting of the arctic», says Vila-Costa.

Warmer water has less density and more salinity (more mineral salt content), so it circulates through the most superficial layers of the ocean. Colder water, on the other hand, has more density and sinks to deeper layers.

The AMOC (for its acronym in English), a gigantic ocean “conveyor belt” that redistributes heat throughout the planet. «This is responsible for the fact that, for example, we do not have the same winters as New York despite being at the same latitude.

A collapse of this current would alter the climate in many parts of the planet. A study published in 2015 indicated that the modification of the AMOC would cause widespread cooling of more than 10 degrees in Europe, more sea ice in the North Atlantic and less precipitation.

“There are changes and we are seeing how they are happening, but we cannot be catastrophic,” Maria Vila-Costa, researcher at the IDAEA-CSIC. “We know more and more about our planet and there are also more tools to solve these problems.”