EL COCUY, Colombia (AlertNet) - Omar Lopez doesn't need scientists to tell him that glaciers in El Cocuy national park in north-east Colombia are fast disappearing.
Â?IÂ?ve been walking these mountains since I was a boy and they used to be covered with one big layer of snow," the 25-year-old park ranger and environmentalist says. "But itÂ?s become obvious to the naked eye that some peaks just donÂ?t have any more snow on them.Â?
El Cocuy park has the highest concentration of glaciers in Colombia, forming part of the Andes mountain range. Global warming has caused them to shrink by 2 to 3 percent a year, and if that continues at the current rate, scientists predict the park will lose all its glacial cover within the next two decades.
"If glaciers continue to shrink at the markedly accelerated rates weÂ?ve been registering since the 1980s, thereÂ?ll be very few glaciers left in the Andes in the next four decades,Â? says Jorge Ceballos, glaciologist at the Colombian Institute of Hydrology, Meteorology and Environmental Studies.
Glaciers are like factories of water. Snow and ice melting from them feed rivers all year round. Many towns in and around El Cocuy wholly depend on water originating from glaciers.
Local people have already noticed water levels in rivers fall.
Â?Rivers' water levels are about half what they used to be 25 years ago,Â? says Miguel Herrera, a subsistence farmer and guide who lives in the national park.
He remembers a time when farmers and their mules could not pass through some mountain paths for days because of deep snow. But today some of those areas are permanent bare rocks.
Flows of melt water from El Cocuy's glaciers, which supply water to people living lower down the mountains, are regulated by alpine grassland savannahs, known as "paramos". Paramos act like giant sponges, absorbing, storing and gradually releasing water from glaciers. But as glaciers shrink, melt water flows are becoming thinner and more erratic, meaning that the paramos receive less moisture and risk drying out.
Â?This park is one huge paramo, so itÂ?s here where glaciers are disappearing that itÂ?s really urgent to protect this crucial water supply coming from the endangered paramos,Â? says Roberto Ariano, a senior park ranger.
Glacier retreat has been a wake-up call for local communities to start protecting their water supply.
For the last two years, park rangers have been raising awareness about water conservation in workshops and on a local radio show. More efficient irrigation systems are key to protecting paramos from drying out, and so farmers are increasingly using water sprinklers instead of letting water run freely from springs.
Park workers are planting plants such as cactuses that help keep water in the paramos. They have also set up small conservation areas where cattle grazing is banned and are encouraging farmers to use hay rather than allowing cattle to roam freely on savannahs, which degrades the land.
But getting farmers to adapt their ancient practices is a trying process.
"ThereÂ?s an attitude here among farmers who think they know whatÂ?s best for their lands because theyÂ?ve been cultivating it in the same way for centuries, so itÂ?s hard to get them to change,Â? says Ariano.
Twenty years ago, the notion of climate change barely existed in El Cocuy. Some farmers blamed the few tourists and climbers who stepped on snow as the reason why the regionÂ?s snow-capped mountains were disappearing.
Â?Some people even thought climate change was a lie,Â? says local guide and farmer Herrera.
But as water levels in rivers have continued to fall and weather has become more erratic, local attitudes have slowly began to change.
Â?I canÂ?t say that all farmers are aware of climate change but everyone understands that glacier retreat means less water because we can witness it,Â? says Herrera.
Scientists, who have recently returned to the previously dangerous national park, can now measure just how fast the glaciers are shrinking.
The mountains surrounding El Cocuy park have long been strategic strongholds of the FARC, ColombiaÂ?s left-wing guerrilla group, and over the years the rebels have attacked and besieged local villages. But three years ago, the arrival of government troops has forced the guerrillas to withdraw from the area, which is now safe for scientists to work in.
At a mountain summit in El Cocuy, park rangers and glaciologist CeballosÂ?s team of three scientists battle against sleet and freezing temperatures as they drill measuring poles into key points along a glacier to monitor its retreat. Others record the water levels of emerald-green glacial lakes nearby as condors fly overhead.
The expedition results are cross-checked with satellite imagery which can also reveal glacier retreat. Two years ago, a weather station with solar panels that measures the length and width of some glaciers and snow thickness in real time was installed in the park.
Collecting up-to-date data showing glacier retreat is crucial to urging policy-makers to act on conserving water, glaciologists say. Local residents alone cannot do all the necessary work as funds are scarce and only nine park rangers cover an area of 306,000 hectares.
But these remote highlands where pumas and so-called bespectacled bears roam are far from the corridors of power in ColombiaÂ?s capital Bogota 250 miles (400 km) away.
Despite the obstacles, local guide Lopez remains cautiously optimistic.
Â?Once glaciers disappear, thereÂ?s nothing we can do to bring them back. ItÂ?s irreversible," he says. "But we can mitigate the effects by taking better care of our rivers and other sources of water."
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