Peruvian President Ollanta Humala announces major funding for decontamination plants around the world-famous Lake Titicaca, but climate change poses a greater threat than pollution to the lake and its surroundings.

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Lake Titicaca, the world’s highest navigable lake at nearly 4,000 metres above sea level, and also Latin America’s largest lake with a surface area of more than 8,000km², is among the region’s most well-known geographical landmarks and has become a major destination for tourists visiting the continent. The increase in tourist numbers, and more importantly the rapid growth of cities lining the lake such as Puno (on the Peruvian side) and Copacabana (on the Bolivian side), have put ever-greater pressures on the lake, with the threat of water pollution particularly crucial given its potentially negative consequences for the tourism industry, and far more importantly for the two and a half million people whose livelihoods depend on the lake.

To this end, the Peruvian government’s announcement last week that it is prepared to pour hundreds of millions of dollars into a major operation to clean up the lake’s waters is a most encouraging development. However, recent studies have shown that this staggeringly beautiful lake is faced with a much bigger – and more existential – menace, in the form of climate change.

Last week the Peruvian president, Ollanta Humala, revealed plans to invest US$450m in six new water treatment plants around the lake, in order to begin tackling the growing problems and hazards posed by pollution in the lake and its watershed, which have sparked protests from locals in recent months. The announcement follows on from bilateral talks between Peruvian and Bolivian authorities last month, where the two sides agreed to collaborate in reducing pollution and water contamination in the region. However, Humala has insisted that local authorities must produce a full technical report on the treatment plants, before he gives formal approval to the governmental funding.

The plan would go a long way towards addressing the levels of water pollution, which according to a study carried out last year by Peru’s National Water Authority (ANA by its initials in Spanish) have reached significantly high levels of contamination. Among the symptoms of this are the dangerous levels of metals and phosphates, which are thought to stem from nearby mining and industrial activities. Other sources of pollution include the burgeoning tourist industry around Lake Titicaca, and even streams of untreated waste from homes and businesses as far away as El Alto, one of Bolivia’s largest cities which is located barely 50 kilometres away.

Nevertheless, recent studies have shown that a much larger and longer-term threat to Lake Titicaca comes in the form of climate change, and the impacts that this is increasingly having on the Andean climate and hydrological cycle. In 2009 the lake’s authorities said that water levels had fallen to their lowest since 1949, with 80cm lost over six months during that year’s winter alone, and there was a notable reduction in the lake’s inflow as significant amounts of the river water flowing towards the lake evaporates before it even reaches it.

The authorities claim that climate change has been the overwhelming factor in this transformation, with increased solar radiation in the Andean highlands being accompanied by a decrease in rainfall and the length of the rainy season. Peru’s glaciers, which are the source of many of the Titicaca watershed’s rivers, are being hit particularly hard by the changing climatic conditions, with another study carried out by the ANA last year finding that the country’s glaciers had shrunk by about 40% in the last 40 years. Other research suggests that Peru’s glaciers could disappear completely within half a century as the region’s highlands continue to warm at a much faster pace than the global average.

More recent satellite images reveal the extent to which the lake’s shoreline has receded over the course of a few decades, but academic research suggests that far worse could yet be in store if global carbon emissions continue to push global warming towards the internationally-set 2°C rise – a limit that will easily be passed on current emissions trends. A 2010 paper (quoted here) used advanced modelling to predict that if average global temperature do rise by this amount, Lake Titicaca would likely shrink by as much as 85%, virtually wiping it out with catastrophic consequences for agriculture and livelihoods in the surrounding areas.

However, Lake Titicaca is by no means the only body of water increasingly coming under attack from climate change and pollution. Late last year, Bolivian authorities were forced to declare a disaster zone around Lake Poopo, the country’s second largest lake after Titicaca, after pollution and low water levels led to the deaths of thousands of fish and animals. The takeaway lesson from all of this is that rescuing the region’s lakes will be a long and costly process, of which the initiative promised by President Humala is just the start. But the alternative, of leaving Lake Titicaca and other areas to their fate, would be unbearable for the millions of people who depend on these fragile environments.

A video report from 2009 documents the strain that Lake Titicaca has already started to feel from the impacts of climate change