West Siberia (10m),1960 to 2005
Izrael et al., 2006
Qinghai-Tibet Plateau (1975 to 1989)
+0.2 to +0.3°C
Cheng and Wu, 2007
Northern Tian Shan (1973 to 2003)
+0.2° to +0.6°C
Khentei and Khangai Mountains, Lake Hovsgol (1973 to 2003)
+0.3° to +0.6°C
10.2.4.2 Hydrology and water resources
Rapid thawing of permafrost (Table 10.4) and decrease in depths of frozen soils (4 to 5 m in Tibet according to Wang et al., 2004b) due largely to rising temperature has threatened many cities and human settlements, has caused more frequent landslides and degeneration of some forest ecosystems, and has resulted in increased lake-water levels in the permafrost region of Asia (Osterkamp et al., 2000; Guo et al., 2001; Izrael and Anokhin, 2001; Jorgenson et al., 2001; Izrael et al., 2002b; Fedorov and Konstantinov, 2003; Gavriliev and Efremov, 2003; Melnikov and Revson, 2003; Nelson, 2003; ACIA, 2005).
In drier parts of Asia, melting glaciers account for over 10% of freshwater supplies (Meshcherskaya and Blazhevich, 1990; Fitzharris, 1996; Meier, 1998). Glaciers in Asia are melting faster in recent years than before, as reported in Central Asia, Western Mongolia and North-West China, particularly the Zerafshan glacier, the Abramov glacier and the glaciers on the Tibetan Plateau (see Section 10.6.2) (Pu et al., 2004). As a result of rapid melting of glaciers, glacial runoff and frequency of glacial lake outbursts causing mudflows and avalanches have increased (Bhadra, 2002; WWF, 2005). A recent study in northern Pakistan, however, suggests that glaciers in the Indus Valley region may be expanding, due to increases in winter precipitation over western Himalayas during the past 40 years (Archer and Fowler, 2004).
In parts of China, the rise in temperature and decreases in precipitation (Ma and Fu, 2003; Wang and Zhai, 2003), along with increasing water use have caused water shortages that led to drying up of lakes and rivers (Liu et al., 2006; Wang and Jin, 2006). In India, Pakistan, Nepal and Bangladesh, water shortages have been attributed to rapid urbanisation and industrialisation, population growth and inefficient water use, which are aggravated by changing climate and its adverse impacts on demand, supply and water quality. In arid Central and West Asia, changes in climate and its variability continue to challenge the ability of countries in the arid and semi-arid region to meet the growing demands for water (Abu-Taleb, 2000; UNEP, 2002; Bou-Zeid and El-Fadel, 2002; Ragab and Prudhomme, 2002). Decreasing precipitation and increasing temperature commonly associated with ENSO have been reported to increase water shortage, particularly in parts of Asia where water resources are already under stress from growing water demands and inefficiencies in water use (Manton et al., 2001).
Global warming and sea-level rise in the coastal zone of Boreal Asia have influenced sea-ice formation and decay, thermoabrasion process, permafrost and the time of river freeze-up and break-up in recent decades (ACIA, 2005; Leont'yev, 2004). The coastlines in monsoon Asia are cyclone-prone with ~42% of the world's total tropical cyclones occurring in this region (Ali, 1999). The combined extreme climatic and non climatic events caused coastal flooding, resulting in substantial economic losses and fatalities (Yang, 2000; Li et al., 2004a). Wetlands in the major river deltas have been significantly altered in recent years due to large scale sedimentation, land-use conversion, logging and human settlement (Lu, 2003). Coastal erosion in Asia has led to loss of lands at rates dependent on varying regional tectonic activities, sediment supply and sea-level rise (Sin, 2000). Salt water from the Bay of Bengal is reported to have penetrated 100 km or more inland along tributary channels during the dry season (Allison et al., 2003). Severe droughts and unregulated groundwater withdrawal have also resulted in sea-water intrusion in the coastal plains of China (Ding et al., 2004).
Over 34% of the vast and diverse coral reefs of Asia that are of immense ecological and economic importance to this region (Spalding et al., 2001; Burke et al., 2002; Zafar, 2005) particularly in South, South-East and East Asia are reported to have been lost in 1998, largely due to coral bleaching induced by the 1997/98 El Niño event (Wilkinson, 2000; Arceo et al., 2001; Wilkinson, 2002; Ministry of the Environment and Japanese Coral Reef Society, 2004; Yamano and Tamura, 2004). The destructive effects of climate change compound the human-induced damages on the corals in this region. A substantial portion of the vast mangroves in South and South-East Asian regions has also been reportedly lost during the last 50 years of the 20th century, largely attributed to human activities (Zafar,
2005). Evidence of the impacts of climate-related factors on mangroves remain limited to the severe destruction of mangroves due to reduction of freshwater flows and salt-water intrusion in the Indus delta and Bangladesh (IUCN, 2003a).
Increasing intensity and spread of forest fires in Asia were observed in the past 20 years, largely attributed to the rise in temperature and decline in precipitation in combination with increasing intensity of land uses (Page et al., 2002; De Grandi et al., 2003; Goldammer et al., 2003; FFARF, 2004; Isaev et al., 2004; Murdiyarso et al., 2004; Shoigu, 2004; Vorobyov, 2004; Achard et al., 2005; Murdiyarso and Adiningsih, 2006). During the last decade, 12,000 to 38,000 wild fires annually hit the boreal forests in North Asia affecting some 0.3 to 3 million hectares (Dumnov et al., 2005; Malevski-Malevich et al., 2005; FNCRF,
2006). Recent studies have also shown a dramatic increase of fires in Siberian peatlands (of which 20 million ha were burnt in 2003) linked to increased human activities combined with changing climate conditions, particularly the increase in temperature. Fires in peatlands of Indonesia during the 1997 to 98 El Niño dry season affected over 2 million ha and emitted an estimated 0.81 to 2.57 PgC to the atmosphere (Page et al., 2002). In the past 10 years about 3 million ha of peatland in South-East Asia have been burnt, releasing between 3 to 5 PgC, and drainage of peat has affected an additional 6 million ha and released a further 1 to 2 PgC. As a consequence of a 17% decline in spring precipitation and arise in surface temperature by 1.5°C during the last 60 years, the frequency and aerial extent of the forest and steppe fires in Mongolia have significantly increased over a period of 50 years (Erdnethuya, 2003). The 1997/98 ENSO event in Indonesia triggered forest and brush fires in 9.7 million hectares, with serious domestic and trans-boundary pollution consequences. Thousands of hectares of second growth and logged-over forests were also burned in the Philippines during the 1997/98 ENSO events (Glantz, 2001; PAGASA, 2001).
With the gradual reduction in rainfall during the growing season for grass, aridity in Central and West Asia has increased in recent years, reducing growth of grasslands and increasing bareness of the ground surface (Bou-Zeid and El-Fadel, 2002). Increasing bareness has led to increased reflection of solar radiation, such that more soil moisture is evaporated and the ground has become increasingly drier in a feedback process, thus adding to the acceleration of grassland degradation (Zhang et al., 2003).
Wetlands in Asia are being increasingly threatened by warmer climate in recent decades. The precipitation decline and droughts in most delta regions of Pakistan, Bangladesh, India and China have resulted in the drying up of wetlands and severe degradation of ecosystems. The recurrent droughts from 1999 to 2001, as well as the building of an upriver reservoir and improper use of groundwater, have led to drying up of the Momoge Wetland located in the Songnen Plain (Pan et al., 2003).
Biodiversity in Asia is being lost as a result of development activities and land degradation (especially overgrazing and deforestation), pollution, over-fishing, hunting, infrastructure development, species invasion, land-use change, climate change and the overuse of freshwater (UNEP, 2002; Gopal, 2003). Though evidence of climate-related biodiversity loss in Asia remains limited, a large number of plant and animal species are reported to be moving to higher latitudes and altitudes as a consequence of observed climate change in many parts of Asia in recent years (Yoshio and Ishii, 2001; IUCN, 2003a). Changes in the flowering date of Japanese Cherry, a decrease in alpine flora in Hokkaido and other high mountains and the expansion of the distribution of southern broad-leaved evergreen trees have also been reported (Oda and Ishii, 2001; Ichikawa, 2004; Kudo et al., 2004; Wada et al., 2004).
A large number of deaths due to heatwaves - mainly among the poor, elderly and labourers such as rural daily wage earners, agricultural workers and rickshaw pullers - have been reported in the Indian state of Andhra Pradesh, Orissa and elsewhere during the past five years (Lal, 2002). Serious health risks associated with extreme summer temperatures and heatwaves have also been reported in Siberian cities (Zolotov and Caliberny, 2004).
In South Asia, endemic morbidity and mortality due to diarrhoeal disease is linked to poverty and hygiene behaviour compounded by the effect of high temperatures on bacterial proliferation (Checkley et al., 2000). Diarrhoeal diseases and outbreaks of other infectious diseases (e.g., cholera, hepatitis, malaria, dengue fever) have been reported to be influenced by climate-related factors such as severe floods, ENSO-related droughts, sea-surface temperatures and rainfall in association with non-climatic factors such as poverty, lack of access to safe drinking water and poor sewerage system (Durkin et al., 1993; Akhtar and McMichael, 1996; Bouma and van der Kaay, 1996; Colwell, 1996; Bangs and Subianto, 1999; Lobitz et al., 2000; Pascual et al., 2000; Bouma and Pascual, 2001; Glantz, 2001; Pascual et al., 2002; Rodo et al., 2002).
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