GeoLog

Argentina

Imaggeo on Mondays: The glacier surviving climate change

Imaggeo on Mondays: The glacier surviving climate change

Human impacts on the climate are nowadays clearly discernible, and the changes to our climate that previously happened in geologic time scales are currently happening during the span of a human lifetime. Our planet is warming and temperature today is now more than 1°C higher than it was in the pre-industrial world and rises by about 0.15-0.2°C on average each decade. The dramatic effects of this rapid climate change are appearing right now: the increasing temperatures are melting glaciers and sea ice all over the world, shifting precipitation patterns and inducing extreme weather events, destroying habitats and forcing animals and people to migrate.

In this climate changing system, glaciers and sea ice represent very fragile elements. Glacier ice occupies about 10 percent of the world’s total land area and stores around 70 percent of the world’s total freshwater. When glaciers melt, freshwater is lost and flows into the seas raising the average global sea level. Since the surface of ice reflects sunlight, and thus heat, ice loss intensifies global warming. Despite this global glacier-melting trend, there are a few glaciers that are growing, one of which is the Perito Moreno Glacier. Scientists are not exactly sure why this glacier is advancing instead of retreating, but some hypothesize that precipitation shifts due to climate change or the glacier’s steep angle could be responsible for the phenomenon.

Located in southwest Santa Cruz Province of Argentina, the Perito Moreno Glacier is one of the region’s many glaciers, which collectively cover about half of the surface of Los Glaciares National Park, a UNESCO World Heritage Site. The glacier belongs to the Southern Patagonian Ice Field, which is the third largest freshwater reserve on the planet after the Antarctic and Greenland ice sheets. Perito Moreno Glacier descends from about 2100 metres in the Andes Mountains, down into the water of Lago Argentino at about 180 metres above sea level. It stretches for 30 km in length and 5 km in width (roughly equivalent in size to the Belgian capital Brussels) and rises 70 meters above the water surface of the lake. The glacier was formed during the last ice age, and is estimated to be 18,000 years old.

The current picture captures the front of the Perito Moreno Glacier from the Lago Argentino bank. By walking the last kilometres of the road which follows the lake shore from the entrance of the park to the main viewpoint, suddenly from between the green of the forest and the turquoise of the lake your sight is captured by the glacier: the white sleeping giant which lays quietly between the sides of the mountains. Coming closer and closer you start to feel the fresh air coming from the mouth of the glacier and hear its noisy breathing produced by the incessant ice cracking. From time to time you can also witness its mumbling, caused by calving ice slabs that fall into the water. The beauty of Perito Moreno Glacier is impressive, however its resistance against climate change is much more incredible. How long will this glacier still be able to resist?

By Magdalena Stefanova Vassileva, GFZ German Research Centre for Geosciences, Germany

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

Imaggeo on Mondays: how short-term storms can impact our landscapes

Imaggeo on Mondays: how short-term storms can impact our landscapes

In the Sierra de Aconquija, a mountain range in the southern Central Andes of Argentina, strong storms often come and go at a moment’s notice, but they can have a long-lasting impact on the Earth’s surface.

The thunderstorm cell featured in this photo formed in less than half an hour, giving all those nearby only a few minutes to take cover. Mitch D’Arcy, a geomorphologist and postdoctoral researcher at the University of Potsdam and the GFZ German Research Centre for Geosciences, had the opportunity to witness this storm (and snap this picture!) while carrying out field work in the area.

“It was a spectacular experience, pouring heavy rain onto a very localised part of the mountain range, but it was also a hazard because the storm was quickly moving towards us with a lot of lightning. Without any trees around, we were likely targets for lightning strikes!” said D’Arcy. Luckily, he and his colleagues were able to find shelter in their truck while the huge downpour passed over them.

These kinds of thunderstorms are short-lived, but have intense precipitation rates. In this case, the temperature dropped by 14 degrees Celsius, and the storm was accompanied by heavy hail and lightning. And while these natural hazards are transient, they can have a long-term impact on the region’s landscape. Severe storms are capable of triggering landslides and floods and can relocate large amounts of sediment and debris in a short period of time.

D’Arcy is part of an international research programme called StRATEGy (Surface processes, Tectonics and Georesources: The Andean foreland basin of Argentina), which looks into how past and present climate change makes a mark on the terrain of the Argentine Andes, among other topics.

This research is essential for understanding and predicting how human-caused climate change will alter weather patterns and impact surface processes (such as how quickly sediments are eroded and transported across landscapes), according to D’Arcy. Having a better understanding of these surface processes and their sensitivity to the climate could help scientists better inform the public about how to prepare for natural hazards, such as flooding, erosion and landslides.

D’Arcy notes that it’s also important to assess how climate and weather trends will impact the sedimentary record, since it is one of the only physical records that scientists can use to examine how the Earth’s surface has change through time.

“North-western Argentina is a fascinating place to study how climate change affects surface processes, because it has experienced pronounced and abrupt changes in hydroclimate through time,” said D’Arcy. Their research has found that even subtle changes in the region’s climate have produced large changes to the surface environment, impacting how rivers take shape and how sediments move.

For example, while the Sierra de Aconquija is a semi-arid environment today, more than 12,000 years ago it used to be much wetter as a result of global climate changes. In fact, back then the mountain range was covered in glaciers and many of the basins were filled with lakes.

“It’s really important that we understand how different landscapes function and how they react to changes in climate. When we look at places like the southern Central Andes in Argentina, we find that the landscape records interesting signatures of ancient climate changes in Earth’s past. However, one of the big questions we still don’t have a good answer to, is how important are these very intense but rare storms for shaping landscapes and creating the sedimentary record from the geological past,” said D’Arcy.

By Olivia Trani, EGU Communications Officer

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

Imaggeo on Mondays: The changing landscape of Patagonia

Imaggeo on Mondays: The changing landscape of Patagonia

Pictured here is a snapshot of an environment in transition. Today’s featured photo was taken at the foot of Monte Fitz Roy, a jagged Patagonia mountain located in Los Glaciares National Park on the border between Argentina and Chile.

The Patagonia region in South America is the second biggest source of glaciers in the southern hemisphere, behind Antarctica, but the region is losing ice at a rapid rate.

Satellite imagery analysis over the last few years has suggested that the Patagonia region is losing ice more than any other part of South America, with some glaciers shedding ice faster than any place in the world.

A recent study reported that the northern and southern Patagonia ice fields in particular are losing roughly 17 billion tons of ice each year. Los Glaciares National Park alone is home to around 50 large glaciers, but because of warming temperatures, almost all of these large ice masses have been shrinking over the last 50 years.

This level of glacial ice loss can be hard to fully imagine, but in 2017, Shauna-Kay Rainford, a PhD student at Pennsylvania State University in the United States and photographer of this featured image, got a first-hand glimpse of Patagonia’s changing landscape.

“Ensconced between the granite boulders I felt like I was at a pivotal moment of continued change,” said Rainford. “While the peaks of Mt. Ritz Roy remain and will likely remain tall and majestic, with each passing year the glacier continues to retreat further towards the peak and the glacial lake continues to expand more and more.”

Rainford had reached this scenic yet tragically ephemeral view after a strenuous hike up the mountain. “It was very emotional to think about what this view will look like in the future if I should ever visit the mountain again,” Rainford recalls. “It is always striking to be confronted with the adverse consequences of human actions.”

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

Imaggeo on Mondays: Cordillera de la Sal

Imaggeo on Mondays: Cordillera de la Sal

The photograph shows the Valle de la Luna, part of the amazing Cordillera de la Sal mountain range in northern Chile. Rising only 200 metres above the basin of the Salar de Atacama salt flat, the ridges of the Cordillera de la Sal represent a strongly folded sequence of clastic sediments and evapourites (salt can be seen in the left portion of the image), with interspersed volcanic material.

This formation evolved when the depression between the Cordillera Domeyko mountain range and the main Andean mountain ranges, filled by an ancient salt flat, was squeezed together over the last 10-15 million years, leaving behind the folded belt of hills seen today. Sand brought along from adjacent areas by the winds was caught between the ridges of the Cordillera de la Sal, accumulating to form the impressive dune shown in the foreground of the image.

Under normal conditions, the perfectly shaped Licancabur Volcano, forming the border between Chile and Argentina, would appear in the background of this sunset scene. However, the image was taken during the Invierno Boliviano (Bolivian winter), when humid air from the eastern side of the Andes travels west across the Andean Plateau, Altiplano. The air masses journey all the way to the otherwise extremely arid Atacama Desert, bringing clouds, rain and occasionally even hail.

I have been to this area three times: first for vacation, then two times for excursions with students, most recently in February this year. Interestingly, the weather was as to be expected for the Atacama Desert only one time. For the two other times, the weather was looking like this photograph, so it is hard for me to believe that the Atacama would be as arid as people always say. However, indeed, the pieces of geological and geomorphological evidence, such as the folded layers of the Cordillera de la Sal, clearly indicate its extreme aridity, prevailing for tens of millions of years!

By Martin Mergili, University of Vienna

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.