Background
Mountains play a pivotal role in the global climate system, acting as indicators of environmental change and serving as water towers for billions of people living in the mountains and downstream. However, in recent years, mountain ecosystems are particularly sensitive to the impacts of climate change and are being affected at a faster rate than other terrestrial habitats. Forty percent of the world’s population rely indirectly on mountain resources for drinking water, agriculture, biodiversity, and hydroelectricity, which could be lost because of global warming.
Climate change is also likely to increase exposure to hazards, with extreme events such as avalanches and landslides becoming more common. The impacts of climate change in mountains and their attribution to human influence have increased in recent decades with observable and serious consequences for people and ecosystems in many mountain regions. Observed changes include increasing temperatures, changing seasonal weather patterns, reductions in snow cover extent and duration at low elevation, loss of glacier mass, increased permafrost thaw and an increase in the number and size of glacier lakes.
This session is designed to foster exchange of information and knowledge on the science and evidence of climate change in the mountains by bringing policy makers, scientists, practitioners, and civil society organizations together to enrich the understanding.
The science and evidence on climate change impact, vulnerability and risks in the mountain region is evolving. Recent scientific findings have come up with strong evidence that clearly project the sensitivity and risks of the mountain system. Climate change impact is visible in terms of loss of biodiversity, water resource depletion, declining crop yield and emerging disease outbreaks.
The spatial distributions of many plant species have shifted to higher elevations in recent decades, consistent with rising temperatures across most mountain regions. Around two-thirds of treeline ecotones have also shifted upwards in recent decades, though these shifts are not ubiquitous and slower than expected based on rising temperatures. Impacts on biological communities and animal species are also increasingly being reported, with species of lower elevations increasing in mountain regions, creating more homogeneous vegetation, and increasing risks to mountain-top species.
Climate and cryosphere change have negatively impacted the water cycle in mountains, including variable timing of glacier melt and snowmelt stream discharge). Mountains are an essential source of freshwater for large and growing populations; the number of people largely or fully dependent on water from mountains has increased worldwide from approximately 0.6 billion in the 1960s to approximately 2 billion in the past decade, and globally two-thirds of irrigated agriculture depends on essential runoff contributions from mountains.
Climate-change-driven changes in precipitation, river flow regimes and landslides affect the production and use of energy in mountain regions, in particular hydropower. Billions of USD in investment and assets of energy production are exposed to changing mountain hazards.
They are largely negative impacts of climate change on mountain ecosystem services, agriculture, and pastoralism. Agriculture has been negatively affected through increased exposure to hazards such as droughts and floods, changes in the onset of seasons, the timing and availability of water, increasing pests and decreasing pollinator diversity, which in turn have negatively influenced overall food production, dietary diversity, and the nutritional value of food. Negative climate impacts on pastoralism, such as drought-induced degradation of rangelands and pastures, have affected livestock productivity and the livelihood of pastoralists, while other non-climatic factors, such as land use change and management, also play a role.
Climate change impacts, and risks are becoming more complex and difficult to manage, often threatening the livelihoods of mountain communities. Climate-related hazards, such as flash floods and landslides, have contributed to an increase in disasters affecting a growing number of people in mountain regions and areas further downstream. As a result, the number of disasters has increased. Scientific evidence suggests that loss and damage are unequally distributed and not comprehensively addressed by current adaptation and mitigation, particularly in vulnerable developing countries. In addition, climate change impacts are disproportionate and will have more severe impact on vulnerable communities.
The IPCC AR6 report emphasizes a few core messages related to loss and damage across topics and sectors. Firstly, the need to mitigate emissions to avert loss and damage is urgent; every degree of warming greatly increases the risks of future loss and damage. Furthermore, the scale of loss and damage is staggering, with up to an estimated 3.6 billion people highly vulnerable to climate-related loss and damage. The residual risk reaches all continents and all sectors but is particularly severe where vulnerabilities and exposure are concentrated, including small island states, East, West, and Central Africa, Central America, coastal cities, informal settlements within cities, rapidly growing small and medium-sized cities.
The session consists of a keynote speech covering the overarching issues and prospects of science and evidence of mountain and climate change followed by high level panel discussions within each theme focusing on nuances and prospects of strengthening science and evidence in the region.
It is expected that this thematic session will enhance collaboration among mountainous countries, leading to improved evidence generation on climate change impacts and fostering better access to loss and damage funds. It will further lead to discussion around the prioritization of mountain communities in climate change negotiations, resulting in improving adaptive capacity and resilience to changing climatic.