Climate change in the Himalayas
The Himalayas are the “third Pole” of the Earth, and form the largest body of ice outside the polar regions. They are the source of fresh water for a large number of rivers that flow across the Indo-Gangetic plains. The Himalayan glaciers support perennial rivers such as the Indus, Ganga and Brahmaputra, which support millions of people in South Asian countries (Pakistan, Nepal, Bhutan, India and Bangladesh). Therefore, any catastrophic change in the mountain ecosystem directly affects the lives of the people who live here, who depend directly or indirectly on the waterbodies in the mountains.
The Intergovernmental Panel on Climate Change (IPCC), claims that many Himalayan glaciers are retreating faster than in any other part of the world. However, the extent to which the Himalayan glaciers are expected to melt is uncertain.It is likely that only small glaciers will disappear in the near future, whereas large glaciers located above 5500-6000m will not disappear in this century (Vetaas 2007).
Many studies suggest that warming in the Himalayas has exceeded the global average of 0.74°C over the last 100 years (Solomon et al 2007).The rise in temperature threatens the mountain ecosystem (Shrestha et al. 1999; Nogues-Bravo et al. 2007; Colwell et al. 2008). However, mountain regions are characterized by a complex topography, which helps to provide a spatial buffer for climate change (Peterson et al. 1997). Thus, a small change in temperature does not have a huge impact on the mountain ecosystem, since a short shift uphill can be sufficient to buffer small rise in temperature(Sandel et al. 2011). Due to this topographic effect, the spatial velocity of temperature change is very high in mountain biomes of lower latitudes in comparison to plateaus at higher latitudes (Loarie et al. 2009).
The ranges of plants and animals are moving in response to recent climate change (Parmesan and Yohe 2003), and the dispersal limits of these species determines their vulnerability to local extinction (Sandel et al 2011). Species that have high dispersal capacities are less vulnerable to climate change than species with weak dispersal capacities (Loarie et al. 2009;Sandel et al. 2011).Thus, plateaus ,which are supposed to be most vulnerable to climate change tend to have species which have high dispersal capacities, whereas species which have low dispersal capacities remain in the mountains (Sandel et al. 2011).
Climate change velocity is a measure of the local rate of displacement of climatic condition over the Earth’s surface (Loarie et al 200), and is calculated by dividing the rate of climate change through time by the local rate of climate change across space (Sandel et al 2011). It has been demonstrated that the regions with the highest spatial velocity of climate change have more endemic species, and the regions with a lower spatial velocity of climate change have few endemic species(Sandel et al. 2011). Thus, mountains which have a high spatial climate velocity, support the most endemic species on earth.
The Himalayan Mountains, are likely to experience extensive changes in the environment, biodiversity, and socioeconomic conditions. Land use and land cover changes are probably the reason behind the recent changes in ecosystem functioning in the mountains (Munsi et al. 2010).The rates of loss and fragmentation in Himalayan forests pose a great threat to global biodiversity (Nautiyal and Kaechela 2007). Land use and land cover changes are the most important and easily measurable indicators of global ecological change (Lambin et al. 2001; Di Gregorio 2005). They have a direct impact on mountain biological diversity (Sala et al. 2000), which contributes to local, regional, and global climate change (Chase et al. 1999; Houghton et al. 1999). Land use and land cover change may cause land degradation by altering ecosystem services and livelihood support systems that affect the vulnerability of people (Sharma et al. 2009).
People living in the mountains are highly affected by the impact of extreme weather events. However, most of the people living in the developing world have no idea about the severe impact of long-term climate change in the mountain regions (Sharma et al. 2009). They have faced disasters all year around, including floods, increasing temperatures, storms, rainfall in the high mountains, irregular rainfall and drought. The Seti Flood in Kaski, Nepal ( in 2012) is just one example. The massive Ice-landslide on Annapurna IV (7525m.) blocked the gorge of the Seti river, and caused the devastating flood that killed 72 people and swept away various settlements (IUCN 2012).
The effects of global change in the Himalayas could ruin thousands of lives in the region, however, only few detailed studies have been carried out on observed land use and land cover change (Nautiyal and Kaechela 2007), as well as climate change (Solomon et al. 2007; Nogues-Bravo et al. 2007), and any generalizations that have been made from those could be challenging in making policies. Although the global community is currently trying to understand the effects of climate change on mountain ecosystems, a huge information gap needs to be overcome to understand Himalayan ecosystem functioning, and to maintain ecosystem resilience.
References
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By Prakash Bhattarai
Interesting post, Prakash! One of the dangers in trying to identify global tipping points to climate change is missing out on the changes occurring (which can be large) at a local scale.
Seddon and his colleagues’ recent research identified ecologically sensitive (terrestrial) areas (see http://www.nature.com/nature/journal/vaop/ncurrent/full/nature16986.html), at 0.05-degree resolution (pretty cool research).
It seems that ecosystem modelling will be a ripe area of research in the future.
It is not easy to move the species up in mountains like in Himalaya. It takes long time to form soil around glacier retreated land. Despite the dispersal capacity of species and favored climate up there, it will be hard to establish in new area up there.
You wrote about a very important topic, one that highlights how vulnerable alpine communities are to climate change and land use change. How would you reckon we should go about protecting the most vulnerable species and those least capable of dispersing in the Himalayas? Should we manually shift the species upwards (which reduces their habitable area as mountains reduce in area towards the top..)? Is it even worth considering a single-species approach to conservation here, or should we focus more on the ecosystem approach, to maintain a functioning ecosystem that can provide people with required ecosystem services (which seems to be what you are leaning towards here)? The effects of floods, for example, can be alleviated by reducing tree logging, so more trees can hold soil in place, which I’m guessing is particularly important in alpine habitats! But are there any essential specific species that should be focused on, that are perhaps both culturally iconic and could be part of an ecosystem approach to conservation?
You wrote about a very important topic, one that highlights how vulnerable alpine communities are to climate change and land use change. How would you reckon we should go about protecting the most vulnerable species and those least capable of dispersing in the Himalayas? Should we manually shift the species upwards (which reduces their habitable area as mountains reduce in area towards the top..)? Is it even worth considering a single-species approach to conservation here, or should we focus more on the ecosystem approach, to maintain a functioning ecosystem that can provide people with required ecosystem services (which seems to be what you are leaning towards here)? The effects of floods, for example, can be alleviated by reducing tree logging, so more trees can hold soil in place, which I’m guessing is particularly important in alpine habitats! But are there any essential specific species that should be focused on, that are perhaps both culturally iconic and could be part of an ecosystem approach to conservation?