el niño El Niño means glaciers in the Andes are melting at record rates

[Reefa]

Tropical glaciers in the Andes are melting at their fastest rate for 12 years, thanks to the record-breaking El Niño that is warming up the area, according to new data analysed for New Scientist.

 

This is compounding the already high melting rates from global warming that will consign many glaciers to history within decades.

 

“The lower-level glaciers in the Andes, below 5500 metres, are really endangered now and probably only have a couple of decades left,” says Michael Zemp, director of the World Glacier Monitoring Service in Zurich, Switzerland. The organisation recently found that the first decade of the 21st century saw the greatest decadal loss of glacier ice ever measured, with melting rates two to three times higher than in the 20th century.

Unique record of Earth’s past

This glacier loss will lead to water and hydropower shortages, the destruction of unique habitats home to endemic species, as well as the loss of a unique record of Earth’s past recorded in layers of ice (see box, below).

 

Doug Hardy, a climate scientist at the University of Massachusetts, has recorded the lowest snow accumulation in the 12 years he has been monitoring the Quelccaya Ice Cap in Peru (pictured above) – the largest glacier in the tropics. “We’re seeing 40 per cent more melting than any other year since measurements started in 2002,” he says.

 

Similarly, the Conejeras glacier in Colombia has lost 43 per cent of its volume over the last two years, according to Jorge Luis Ceballos Liévano and his colleagues from the Hydrology, Meteorology and Environmental Studies Institute in Bogotá. More than two-thirds of that loss has taken place since the onset of the current El Niño.

Rising snowline

“2015 was particularly bad for this glacier and if losses persist it is possible that it will be extinct by 2030 or before,” says Liévano. “Conejeras is representative of what is happening elsewhere in the Andes.”

 

For example, the once-continuous ice mass along the crest of the Sierra Nevada del Cocuy in Colombia is now a series of broken patches. Measurements show that the snowline has risen above most of the mountain summits now. “In Colombia there is no accumulation of ice and so we anticipate that these glaciers will only have around 20 years

,” says Zemp.

 

The Zongo glacier in Bolivia, whose runoff feeds a hydroelectric power station supplying the capital, La Paz, also appears to be in its death throes.

Some glaciers already extinct

Some glaciers have already melted away. In 2009, the last of the ice disappeared on the 5350-metre-high Chacaltaya glacier in Bolivia – previously the world’s highest ski resort (pictured below). Similarly the ice-covered summit of Pico Espejo in Venezuela became bare rock by 2008.

 

In Bolivia and Peru, which have arid summers, glaciers buffer the water supply and ensure a year-round steady flow.

 

Last year Antoine Rabatel, from the Joseph Fourier University in Grenoble, France, and colleagues showed that during the dry season a quarter of La Paz’s water comes from glaciers. “Right now people don’t realise the urgency of the situation because the fast melting of the glaciers is providing plenty of water,” says Rabatel.

 

In some locations the nature of things to come is starting to become apparent. Retreat of glaciers in the Quebrada Paron mountains of Peru has reduced water flow into the lake below, which supplies a hydroelectric power plant.

Loss of ecosystems

In 2008, people living downstream in the city of Caraz found themselves short of water for irrigation and decided to take direct action in protest. “They locked access to the touristic high valley of Paron,” says Rabatel. This blocked access to the area both to tourists and scientists. “In this case it was more a problem of managing the water resource, but such problems are likely to become more important as water quantity decreases.”

 

And it isn’t just people who will be affected. Previous research has found that between 11 and 38 per cent of species could be lost in an area following the disappearance of a glacier. Specialist species such as the meltwater stonefly, whose larvae rely on glacial streams, are likely to start vanishing when half the glacial cover in a region is lost. And slow-growing alpine cushion plants, along with many other species of plant and animal that depend on these mossy pillows, will suffer under increasing temperatures. Even though cushion plants prefer to colonise newly deglaciated land, they will struggle to keep up with the pace of melting. The only bird known to nest on a glacier – the white-winged diuca finch (Diuca speculifera) – may have to keep moving higher to build its nests, until eventually it will run out of places to go.

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Race to capture the soul of dying glaciers

Several teams of glaciologists are rushing to drill into remaining glaciers to preserve a sample called an ice core, and with it record of our planet's past.

 

"Some of these glaciers contain 20,000 years' worth of atmospheric data and right now melting is wiping this record out," says Antoine Rabatel from the Joseph Fourier University in Grenoble, France.

 

"We need to preserve these cores now, so that scientists of the future can still extract this information," says his colleague Patrick Ginot, who is leading a UNESCO-supported project - Saving Ice in Danger - to collect and store glacial ice cores at the Concordia Research Station in Antarctica.

 

Lonnie Thompson, from the Ohio State University, and his team have been hauling their specialist solar-powered drilling rigs up to some of the most inaccessible places in the world since 1983. Just last month they returned with ice cores from the Guliya ice cap in north-west Tibet, which they then store in a specialist unit at the university.

 

"This freezer facility is the only place that the ice from some of these glaciers still exists," says Thompson. These glacial ghosts include lost ice fields on Mount Kilimanjaro in East Africa and those from the rapidly melting Northwall Firn glacier on the slopes of Puncak Jaya in Indonesia.

 

Much of our understanding of global climate is based on the high-resolution record of past atmosphere that only ice cores can provide.

 

The cores from the Quelccaya Ice Cap in Peru, for example, show the medieval warm period when the Vikings settled in Greenland. "You can see the onset of the Little Ice Age in the early 1500s that contributed to the demise of the Vikings," says Thompson. "And you can see the warming in the 20th century."

 

"We hope soon to be able to reconstruct the evolution of things like bacteria and viruses through time by using the ice archive," says Thompson.

 

https://www.newscientist.com/article/2075093-el-nino-means-glaciers-in-the-andes-are-melting-at-record-rates/