to worry that they may in fact disappear not in 2035, but even earlier." Further studies in 2009 indicated the rate of glacial melt in Bhutan was three times the world average, and that over the previous three decades regional temperatures had risen by . Satellite imaging also confirmed changes in glaciers and snow peaks, indicating increased runoff and decreased coverage. However, opinions varied on the effect of global warming in the Himalaya. According to US geological survey report, 66 glaciers in Bhutan have decreased by 8.1 percent in the last 30 years. On the other hand, a study whose results were published in 2011 indicated glacial melt depended on several factors including debris cover, and that more than half of the glaciers in the Himalaya were stable or were in fact growing. Debris cover, such as rocks and mud, set apart the relatively stable glaciers of the Himalaya from the pristine glaciers of the Tibetan Plateau, currently in fast retreat. The study, conducted by the Universities of California and Potsdam and published in the journal Nature Geoscience, was based on 286 glaciers along the Himalaya and Hindu Kush from Bhutan to the Afghanistan-Pakistan border. Another preliminary survey conducted by a team of Japanese and Bhutanese scientists, including a glacio-microbiologist, glacio-ecologist and geologist, indicated that the presence of a peculiar microorganism on the surfaces of glaciers could accelerate glacial melting and eventually lead to a glacial outburst. Agriculture In the early 21st century, Bhutanese farmers first experienced agricultural fluctuations due to climate change, including higher temperatures, prolonged seasons, and increased erosion due to retreating glaciers in Bhutan. Double harvests in late autumn prevent production of a single mature crop and raise the specter of reduced yields in the following summer. Similar patterns in neighboring Indian regions project yield losses between 10 and 40 percent due to these changes. Some Bhutanese had changed crops as a result of these environmental changes. Forestry Through the late 20th century, Bhutan's low population and the general absence of overdevelopment contributed to its forest preservation. Because of terrain, more accessible forests had been overcut whereas remote forests remained largely in their natural state through the early 1990s. A progressive government-sponsored forestry conservation policy strove to balance revenue needs with ecological considerations, water management, and soil preservation. Success in managing its forest resources had long been critical to the local environment and economy and also affected