Even if efforts are made to limit global warming to 1.5̊C by the end of the Century, the Hindu Kush Himalaya will warm by around 1.8 ̊C, a comprehensive report on the region has found. The report also finds that warming will at least be 0.7 ̊C higher in the northwest Himalaya and Karakoram region. “The HKH will warm more than the global mean and more rapidly at higher elevations,” the report states.
In other words, even the most ambitious goal set by the Paris Agreement to limit global warming would lead to a 2.1 spike in temperature in the HKH region leading to melting of one-third of the region’s glaciers, potentially “destabilizing” Asia’s rivers, the assessment notes. It also points out that the Tibetan Plateau, Central Himalayan Range and Karakoram will warm more than the HKH average.
The ‘Hindu Kush Himalaya Assessment’ released Monday by the Kathmandu-based International Centre for Integrated Mountain Development (ICIMOD) provides insights into changes affecting one of the greatest mountain systems in the world. Over 350 researchers, practitioners, experts, and policy-makers were involved in drafting the HKH Assessment Report which is styled after the IPCC reports. “This is the climate crisis you haven’t heard of,” said Philippus Wester of ICIMOD in a statement, who led the report. “Global warming is on track to transform the frigid, glacier-covered mountain peaks of HKH cutting across eight countries to bare rocks in a little less than a century…” he said.
HKH covers 3500 kms across eight countries – Afghanistan, Bangladesh, Bhutan, China, India, Myanmar, Nepal and Pakistan – and is the source of ten major river basins including the Ganges, Brahmaputra and Indus in India. Two billion people are dependent on the HKH for their water needs across Asia.
“The warming rate over the last 50 years in the HKH has been 0.2 ̊C per decade. Extreme indices in the region have also changed over this period: occurrences of extreme cold days and nights have declined (days by 0.85 days per decade, nights by 2.40 days per decade), while occurrences of extreme warm days and nights have increased (days by 1.26 days per decade, nights by 2.54 days per decade). Warm nights have increased throughout the region, and extreme absolute temperature indices have changed significantly,” the study notes.
Further, the report warns that extremes in precipitation are increasing in the HKH region. “The number of intense precipitation days and intensity of extreme precipitation have increased overall in the last five decades. If these trends persist the frequency and magnitude of water-induced hazards in the region will increase in the future,” it states. It, however, points out that consensus among climate models for the region is “weak” which is a result of the area’s complex topography and the coarse resolution of global climate models.
The report notes that the cryosphere -parts of the Earth system where water is in frozen form- is an important part of the water supply of the extended HKH. “Observed and projected changes in the cryosphere will affect the timing and magnitude of streamflows across the region, with proportionally greater impacts upstream,” the study notes.
Further, it notes that as a result of climate change, “a consistent increase in streamflow is expected at large scales for the upstream reaches of the Indus, Ganges, and Brahmaputra rivers until at least 2050. In the Indus, this increase will result from increased glacial melt for a limited period, while in the Ganges and the Brahmaputra, it is expected to result mainly from increased precipitation. Pre-monsoon flows are expected to decline, with implications for irrigation, hydropower, and ecosystem services.”
The report also addresses the large impacts of air pollution on the HKH. “The HKH is sensitive to climate change — air pollutants originating within and near the HKH amplify the effects of greenhouse gases and accelerate melting of the cryosphere through the deposition of black carbon and dust, and changing monsoon circulation and rainfall distribution over Asia,” it states. The report calls for greater recognition of mountain areas and the HKH region in global efforts.