Upstream from what was once Lake Poopó sits Lake Titicaca. Straddling the border between Peru and Bolivia, Lake Titicaca is the world’s highest altitude navigable lake. But in recent years, Lake Titicaca has been rapidly losing volume. At the same time, pollution from surrounding agricultural activities and cities, invasive species, and overfishing are further taxing the ecosystem. The combination of human impacts and climate change could result in the loss of one of the most critical water resources for Bolivia and Peru.
Over time, drought and diversions for agricultural and municipal use have drastically reduced the size of Lake Titicaca. According to Circle of Blue, from 2003 to 2010 almost 500 square miles of the lake’s surface were lost, nearly 15 percent of the total. Pollution flows into the lake from the Peruvian city of Puno and the Bolivian cities of La Paz and El Alto, untreated and unmonitored. Estimates indicate that as much as 80 percent of El Alto’s untreated raw sewage and waste eventually trickles into Lake Titicaca. Inflow from glacial sources is sharply declining as well. Even if the post-Paris climate goal of limiting warming to 2 degrees Celsius is met, Lake Titicaca will likely still lose 15 percent more of its current volume due to increased evaporation and decreased inflows.