Climate change is already visible in the Alps. Over the last century, many glaciers have retreated back farther than humans have ever witnessed in historic times. The risk for rock-falls and landslides has significantly increased over time, impacting infrastructure and forcing traditional routes for tourists to close. Plants and animal are migrating in response to changing weather patterns. The water chemistry of many springs, located high in the mountains, is changing as ice hidden in the underground thaws. Temperature and precipitation data, both measured as reconstructed from tree-rings, show significant changes in the last century.
The Alps are among the best-studied mountain ranges worldwide, with a 200-year long history of naturalists and scientists visiting, but what about other mountain ranges? Not all countries can afford to cover their mountains with a network of climate monitoring stations, as is the case in the Alps. Research can be expensive and scientists can't be everywhere.
Many indigenous cultures depend on their surrounding environment and are keen observers of the natural world. Even though their lifestyle has the least impact on rising greenhouse gases, native peoples are at the front-lines of climate change. Once dismissive of stories and anecdotes, climate scientists have become more aware of what locals can tell.
In the Himalayas, some medicine men have noted that finding herbs and ingredients for medicine has become difficult. Many plants either don't grow anymore on traditional sites or no longer fruit and flower at a certain time. Monitoring in the Alps has shown that plants tend to migrate higher in response to a warming climate, but not all plants will profit from the resulting environment. Many mountain plants can't compete with new species, growing stronger and faster than the local species, and are therefore at a higher risk of extinction. If the average global temperature continues to rise in the next decades, 15 to 37 percent of the world's animal and plant species could face extinction. This will not only mark an important biodiversity loss, but also the loss of traditions based on certain animals or plants. In remote regions, without immediate access to modern drugs, the loss of natural remedies, derived from plants and animals could have fatal consequences.
In the mountainous areas of Sweden, Norway, Finland and Russian tundra, milder winters and a reduced snow cover is impacting negatively lichen populations, a key food source for reindeer. Lichens don't need much to survive, but sunlight is vital. Mild winter with less snow favor other plants, like shrubs and trees. Now in the shadow during summer, the lichens, already organisms with slow growth, can't compete any longer with the fast growing species, soon dominating the landscape. The Sami people, traditional reindeer herders, have to search for fodder or are forced to buy supplements, a significant economic impact. The problem will get worse. As the polar regions warm up, evergreen trees will move into the vast treeless Arctic tundra, and in warmer, drier areas, grass will take over from woodland.
The unpredictability of weather systems in a new climate is also one of the greatest threats to indigenous communities. The Akha, mountain tribes in Southeast Asia, experience more pests during the long summer. Hot, dry summers also cause a significant drop in the quality of the harvested tea, leading to economic losses. The loss of glaciers on mountain tops impacts everybody living downslope. Mount Kilimanjaro and the Rwenzori Mountains have lost 80-90 percent of their ice in the last 100 years. The Chagga people live and farm on the slopes of Kilimanjaro. Reduced rainfall and less water from the mountain has disastrous effects on crop yields and the local population. But also arid regions in Asia are already suffering. The water discharged from the glaciers during summer is important to survive here the dry season, glaciers are essential for the local communities.
Climate change also threatens also the history of native communities. The historic Pueblos in the Southwest of the U.S. are now at risk from landslides and sudden, but strong storm events.
Ancient knowledge can provide also more surprising discoveries. The visibility of the Pleiades star cluster during the last days in June is used by farmers in Peru and Bolivia to plan ahead and find the best time to plant their crops. If mist covers the stars, then the rains will be poor. The farmers in response delay the planting of their crops. Scientists discovered a link between this tradition with El Niño, a climate phenomenon with worldwide effects. While scientists know that El Niño reduces rainfall in the Andes, they were previously not aware of the link between El Niño and cloud cover.
