ENVIRONMENTAL AND SOCIETAL IMPLICATIONS OF THE GLOBAL LOSS OF TROPICAL GLACIERS

Glaciers serve both as recorders and sensitive indicators of climate change, and can be considered to be Nature’s best “thermometer”. Ice cores recovered from glaciers and ice sheets contain climate histories that can be reconstructed from aerosols and stable isotopes of water, and they provide biological histories from microbes, pollen and methane. The recent warming in the Tropics is observed in the ice core chemistry and in the retreat of high-altitude ice fields. Because of their size, tropical glaciers respond to changes in temperature and precipitation faster than large polar ice sheets. Many of the world’s high altitude glaciers are monitored by ground observations, aerial photography and satellite-borne sensors. Based on these analyses there is a consensus that almost without exception these ice fields are retreating at an accelerating rate. The populations of Peru and Southeast Asia are particularly vulnerable to glacier response to climate change. The current glacier retreat throughout the Peruvian Andes and the Himalayan region is contributing to emerging water resource crises and environmental hazards for both urban and rural populations. Nowhere is the loss of tropical glaciers better documented and more critical than in the Andes of Peru. The longest documented record of tropical glacier retreat comes from 44-year study on the Quelccaya ice cap (the world’s largest tropical ice cap) in the Cordillera Vilcanota. The climate history from its ice cores and the detailed retreat of its largest outlet glacier Qori Kalis document the accelerating loss of a very important climate archive and of a water resource that feeds the Amazon River to the east and Lake Titicaca to the south. In the Cordillera Blanca in northern Peru all the shallow ice cores drilled below 5,400 masl show the alteration of the climate record from seasonal melting and movement of meltwater through the porous upper firn layers. Because of its high elevation only Huascarán still preserves a largely unaltered climate record; however, this record will also soon be compromised at the current rate of warming. Despite the global scale of evidence of rapid climate warming that has been presented in five IPCC reports since 1990, the world’s governments have failed take the necessary actions to address the advancing crisis.