The Tibetan Plateau and its surroundings contain the largest number of glaciers outside the Polar Regions and are known as the world's "third pole". Glacial and lake changes in the third pole not only lead to changes in atmospheric circulation patterns in the region and the northern hemisphere but also affect agriculture, power generation and the water supplies of 1.5 billion people in the surrounding areas across ten countries. Hence, the situation of the glaciers and lakes of the third pole has attracted attention worldwide. While the Himalaya glaciers are largely retreating, the recent evolution of the Karakoram glaciers, widely acknowledged as peculiar, remains poorly understood. Glacial lakes showed a trend of expansion and the great lakes were shrinking in the Himalayas; but lakes in the Karakoram were considered stable. The causes and mechanisms of the complex and regionally heterogeneous behavior of glacier and lake change between the Karakorum and Himalayas are poorly understood. The Songmuxi Co Basin lies in the transitional zone between the Karakorum and Himalayas, and the glaciers and lakes have a significant impact on the local water supply and ecosystem. In this work, glacial and lake changes in the Songmuxi Co Basin, southern Karakoram Mountains were detected based on 1:50000 topographic maps, Landsat MSS/TM/ETM+/OLI remote sensing data and GIS techniques. The annual temperature, precipitation, potential annual evaporation at Shiquanhe, Hetian and Yutian stations from 1968 to 2013 were used to analyze climate change and its impact on glaciers and lakes area change. The results can be drawn as follows. (1) From 1968 to 2013, the total glacier area decreased from 139.25 km2 to 137.27 km2, a total loss of 1.98 km2, or 1.42% of the entire glacial area in 1968. In addition, there has been an accelerating trend of glacier retreat since 2001. (2) The area of Songmuxi Co expanded from 25.05 km2 in 1968 to 32.62 km2 in 2013. The overall increase was 7.57 km2, which was 30.22% of the lake area in 1968. The lake area expansion and glaciers retreat have a good coupling on a decadal scale. (3) From 1968 to 2013, the decreased potential evapotranspiration in the lake and increased precipitation are of the first and second factors which lead to lake area expansion. The increase in melt water from glaciers and frozen soil due to climate warming had no great impact on lake area expansion on the interannual scale while it may had some impact on the decadal one.
LIZhiguo, LUJie, SHIBenlin, LIHongzhong, ZHANGYanwei, LILin. Glaciers and lake changes (1968-2013) and their causes in the Songmuxi Co Basin, Northwest Tibetan Plateau[J]. 地理研究, 2015, 34(11): 2095-2104 https://doi.org/10.11821/dlyj201511008
Fifth Assessment ReportThe Intergovernmental Panel on Climate Change (IPCC) publishes Assessment Reports every six to seven years, with the IPCC First Assessment report published in 1990. The Fifth Assessment Report is being published in stages across 2013 and 2014.Each of the three Working Groups contributes to the development of Assessment Reports:
Yao TD, ThompsonL, YangW, et al.
Different glacier status with atmospheric circulations in Tibetan Plateau and surroundings.
More than 1.4 billion people depend on water from the Indus, Ganges, Brahmaputra, Yangtze, and Yellow rivers. Upstream snow and ice reserves of these basins, important in sustaining seasonal water availability, are likely to be affected substantially by climate change, but to what extent is yet unclear. Here, we show that meltwater is extremely important in the Indus basin and important for the...
PiaoS, CiaisP, HuangY, et al.
The impacts of climate change on water resources and agriculture in China.
China is the world09銇64s most populous country and a major emitter of greenhouse gases. Consequently, much research has focused on China09銇64s influence on climate change but somewhat less has been written about the impact of climate change on China. China experienced explosive economic growth in recent decades, but with only 7% of the world09銇64s arable land available to feed 22% of the world09銇64s population, China's economy may be vulnerable to climate change itself. We find, however, that notwithstanding the clear warming that has occurred in China in recent decades, current understanding does not allow a clear assessment of the impact of anthropogenic climate change on China09銇64s water resources and agriculture and therefore China09銇64s ability to feed its people. To reach a more definitive conclusion, future work must improve regional climate simulations09恪眅specially of precipitation09恪盿nd develop a better understanding of the managed and unmanaged responses of crops to changes in climate, diseases, pests and atmospheric constituents.
Glacier and lake changes across the Tibetan Plateau during the past 50 years of climate change.
In this paper, recent glacier and lake changes research on the Tibetan Plateau was reviewed. Emphasis was placed on a discussion of the relationship between glacier shrinkage and lake change. In the context of global climate change, the glaciers of the Tibetan Plateau have generally retreated, while the lakes have generally expanded. First, the research on glacial terminal retreat, glacial area and volume variations across the Tibetan Plateau over the last few decades are reviewed and analyzed; the temporal-spatial change characteristics of the glaciers are discussed. Secondly, the lake area, volume and water level changes are reviewed and analyzed; the temporal-spatial change characteristics of the glaciers are discussed. The results indicate that the retreat speed in the outer edge of the Tibean Plateau was overall faster than that in the inland area. The areas and water levels of the lakes that are fed by glacial water increased. Finally, the limitations of the present studies and future work are discussed.
Abstract Glacial lake outburst floods are among the most serious natural hazards in the Himalayas. Such floods are of high scientific and political importance because they exert trans-boundary impacts on bordering countries. The preparation of an updated inventory of glacial lakes and the analysis of their evolution are an important first step in assessment of hazards from glacial lake outbursts. Here, we report the spatiotemporal developments of the glacial lakes in the Poiqu River basin, a trans-boundary basin in the Central Himalayas, from 1976 to 2010 based on multi-temporal Landsat images. Studied glacial lakes are classified as glacier-fed lakes and non-glacier-fed lakes according to their hydrologic connection to glacial watersheds. A total of 119 glacial lakes larger than 0.01 km 2 with an overall surface area of 20.22 km 2 (卤10.8%) were mapped in 2010, with glacier-fed lakes being predominant in both number (69, 58.0%) and area (16.22 km 2 , 80.2%). We found that lakes connected to glacial watersheds (glacier-fed lakes) significantly expanded (122.1%) from 1976 to 2010, whereas lakes not connected to glacial watersheds (non-glacier-fed lakes) remained stable (+2.8%) during the same period. This contrast can be attributed to the impact of glaciers. Retreating glaciers not only supply meltwater to lakes but also leave space for them to expand. Compared with other regions of the Hindu Kush Himalayas (HKH), the lake area per glacier area in the Poiqu River basin was the highest.
Glaciers distinct from the Greenland and Antarctic Ice Sheets are losing large amounts of water to the world’s oceans. However, estimates of their contribution to sea level rise disagree. We provide a consensus estimate by standardizing existing, and creating new, mass-budget estimates from satellite gravimetry and altimetry and from local glaciological records. In many regions, local measurements are more negative than satellite-based estimates. All regions lost mass during 2003–2009, with the largest losses from Arctic Canada, Alaska, coastal Greenland, the southern Andes, and high-mountain Asia, but there was little loss from glaciers in Antarctica. Over this period, the global mass budget was –259 ± 28 gigatons per year, equivalent to the combined loss from both ice sheets and accounting for 29 ± 13% of the observed sea level rise.
NeckelN, KropáčekJ, BolchT, et al.
Glacier mass changes on the Tibetan Plateau 2003-2009 derived from ICESat laser altimetry measurements.
High-elevation inland lakes are a sensitive indicator of climate change. The extents of lakes in Mt. Qomolangma region have been extracted using the object-based image-processing method providing 6-24 images during 1970-2009. Combined with data from five meteorological stations and three periods' glacier data, the inter-annual and intra-annual lake changes and responses to climate and glacier change have been analyzed. The results show that the lakes have shrunk overall, with clear inter-annual and intra-annual fluctuations during 1970-2009. In general, there appeared a trend of slight shrinkage in the 1970s, distinct shrinkage around 1990, general expansion in 2000 and accelerated decrease after 2000. Lake Peiku and neighboring lakes show a highly consistent change trend (correlation coefficients of 0.68-0.91), with larger lakes having smaller shrinkage rates, which implies a higher stability (in the order of Peiku > Langqiang > Cuochuolong). Lake Peiku, the largest lake, decreased 10.38 km(2) (3.69 % or 0.27 km(2) year(-1)) during 1970-2009. The changes in Lake Peiku indicate that precipitation is its main source of supply with glacier melt water a key supplement. Meanwhile, Lake Como Chamling reduced by 13.12 km(2) (19.79 %) during 1974-2007, with strong shrinkage-expansion-shrinkage-expansion fluctuations. Overall, lakes in the vicinity of Mt. Qomolangma are a sensitive good indicator to climate change.
Lei YB, YangK, WangB, et al.
Response of inland lake dynamics over the Tibetan Plateau to climate change.
The water balance of inland lakes on the Tibetan Plateau (TP) involves complex hydrological processes; their dynamics over recent decades is a good indicator of changes in water cycle under rapid global warming. Based on satellite images and extensive field investigations, we demonstrate that a coherent lake growth on the TP interior (TPI) has occurred since the late 1990s in response to a significant global climate change. Closed lakes on the TPI varied heterogeneously during 1976–1999, but expanded coherently and significantly in both lake area and water depth during 1999–2010. Although the decreased potential evaporation and glacier mass loss may contribute to the lake growth since the late 1990s, the significant water surplus is mainly attributed to increased regional precipitation, which, in turn, may be related to changes in large-scale atmospheric circulation, including the intensified Northern Hemisphere summer monsoon (NHSM) circulation and the poleward shift of the Eastern Asian westerlies jet stream.
Song CQ, HuangBo, RichardsK, et al.
Accelerated lake expansion on the Tibetan Plateau in the 2000s: Induced by glacial melting or other processes?
ABSTRACT Alpine lakes on the Tibetan Plateau are minimally disturbed by human activities and are sensitive indicators of climate variability. Accelerated lake expansion in the 2000s has been confirmed by both dramatic lake-area increases (for 312 lakes larger than 10 km2) derived from optical images, and rapid water-level rises (for 117 lakes with water-level data) measur
Zhang GQ, Yao TD, Xie HJ, et al.
Increased mass over the Tibetan Plateau: From lakes or glaciers?
 The mass balance in the Inner Tibet Plateau (ITP) derived from the Gravity Recovery and Climate Experiment (GRACE) showed a positive rate that was attributed to the glacier mass gain, whereas glaciers in the region, from other field-based studies, showed an overall mass loss. In this study, we examine lake's water level and mass changes in the Tibetan Plateau (TP) and suggest that the increased mass measured by GRACE was predominately due to the increased water mass in lakes. For the 200 lakes in the TP with 4 to 7 years of ICESat data available, the mean lake level and total mass change rates were +0.14 m/yr and +4.95 Gt/yr, respectively. Compared those in the TP, 118 lakes in the ITP showed higher change rates (+0.20 m/yr and +4.28 Gt/yr), accounting for 59% area and 86% mass increase of the 200 lakes. The lake's mass increase rate in the ITP explains the 61% increased mass (~7 Gt/yr) derived from GRACE [ Jacob et al ., 2012], while it only accounts for 53% of the total lake area in the ITP.
LiL, LiJ, Yao XJ, et al.
Changes of the three holy lakes in recent years and quantitative analysis of the influencing factors.
Namco Lake, Yamzho Yumco Lake, and Mapam Yamco Lake are the “three holy lakes” of Tibet. Based on the topographic map of 1970 and the Landsat TM/ETM + remote sensing images of 1970 and from 1990 to 2012, satellite altimetry data, observed data from meteorological stations, and the changes of the “three holy lakes” in area, water level and water storage, the lake status and causes of the changes have been analyzed in a comparative manner. From 1970 to 2012, Namco Lake rapidly expanded in area, Yamzho Yumco Lake sharply declined, and Mapam Yamco Lake showed a slight decline with no great changes. The increase in precipitation was the main reason for the expansion of Namco Lake from 1970 to 1998, but the increase in glacial meltwater caused by temperature rise, and the decrease in evaporation from the lake surface, are the main reasons for the expansion and water storage increase of Namco Lake after 1998. Yamzho Yumco Lake significantly expanded from 1991 to 2004 mainly because the evaporation was limited, and shrank after 2004 because of the decrease in precipitation and the increase in evaporation. Mapam Yamco Lake was shrinking due to higher evaporation and lower precipitation. In addition to glacier meltwater, there are other forms of supply, such as groundwater, wetlands, and permafrost ablation.
As one of the areas with numerous lakes on the Tibetan Plateau,the Hoh Xil region plays an extremely important role in the fragile plateau eco-environment.Based on topographic maps in the 1970s and Landsat TM/ETM+ remote sensing images in the 1990s and the period from 2000 to 2011,the data of 83 lakes with the area above 10 km2 were obtained by digitization method and artificial visual interpretation technology,and the causes for lake variations were also analyzed.Some conclusions can be drawn as follows.(1) From the 1970s to 2011,the lakes in the Hoh Xil region firstly shrank and then expanded.In particular,the area of lakes generally decreased during the 1970s-1990s.Then the lakes expanded during the 1990s-2000 and their area was slightly higher compared with the 1970s.The area of lakes dramatically increased after 2000.(2) From 2000 to 2011,the lakes with different area scales in the Hoh Xil region showed an overall expansion trend.Meanwhile,some regional differences were also discovered.Most of the lakes expanded and were widely distributed in the northern,central and western parts of the region.Some lakes merged together or overflowed due to their rapid expansion.A small number of lakes with the trend of area decrease or strong fluctuation were scattered in the central and southern parts of the study area.And their variations were related to their own supply conditions or hydraulic connection with the downstream lakes or rivers.(3) The increase in precipitation was the dominant factor resulting in the expan
Liu SY, Sun WX, Shen YP, et al.
Glacier changes since the Little Ice Age maximum in the western Qilian Shan, Northwest China, and consequences of glacier runoff for water supply.
Based on aerial photographs, topographical maps and the Landsat-5 image data, we have analyzed fluctuations of glaciers in the western Qilian Shan, northwest China, from the Little Ice Age (LIA) to 1990. The areas and volumes of glaciers in the whole considered region decreased 15% and 18%, respectively, from the LIA maximum to 1956.This trend of glacier shrinkage continued and accelerated between 1956 and 1990. These latest decreases in area and volume were about 10% in 34 years. The recent shrinkage may be due either to a combination of higher temperatures and lower precipitation during the period 1956-66, or to continuous warming in the high glacierized mountains from 1956 to 1990. As a consequence, glacier runoff from ice wastage between 1956 and 1990 has increased river runoff by 6.2 km 3 in the four river basins under consideration. Besides, the equilibrium-line altitude (ELA) rise estimated from the mean terminus retreat of small glaciers <1km long is 46 m, which corresponds to a 0.3掳C increase of mean temperatures in warm seasons from the LIA to the 1950s.
Extracting a climate signal from 169 glacier records.
I constructed a temperature history for different parts of the world from 169 glacier length records. Using a first-order theory of glacier dynamics, I related changes in glacier length to changes in temperature. The derived temperature histories are fully independent of proxy and instrumental data used in earlier reconstructions. Moderate global warming started in the middle of the 19th century. The reconstructed warming in the first half of the 20th century is 0.5 kelvin. This warming was notably coherent over the globe. The warming signals from glaciers at low and high elevations appear to be very similar.
YangK, WuH, QinJ, et al.
Recent climate changes over the Tibetan Plateau and their impacts on energy and water cycle: A review.
The Tibetan Plateau (TP) exerts strong thermal forcing on the atmosphere over Asian monsoon region and supplies water resources to adjacent river basins. Recently, the Plateau experienced evident climate changes, which have changed atmospheric and hydrological cycles and thus reshaped the local environment. This study reviewed recent research progress in the climate changes and explored their impacts on the Plateau energy and water cycle, based on which a conceptual model to synthesize these changes was proposed and urgent issues to be explored were summarized.The TP has experienced an overall surface air warming and moistening, solar dimming, and wind stilling since the beginning of the 1980s. The surface warming depends on elevation and its horizontal pattern is consistent with the one of the glacier change. Accompanying the warming was air moistening, and both facilitated the trigger of more deep-clouds, which resulted in solar dimming. Surface wind speed declined from the 1970s, as a result of atmospheric circulation adjustment caused by the differential surface warming between the Asian high-latitude and low-latitude.The climate changes had weakened the thermal forcing over the TP. The warming and wind stilling lowered the Bowen ratio and led to less surface sensible heating. Atmospheric radiative cooling was enhanced, mainly by outgoing longwave emission from the warming planetary system and slightly by solar radiation reflection. Both processes contributed to the thermal forcing weakening over the Plateau. The water cycle was also altered by the climate changes. The wind stilling may have weakened water vapor exchange between the Asia monsoon region and the Plateau and thus led to less precipitation in the monsoon-impacted southern and eastern Plateau, but the warming enhanced land evaporation. Their overlap resulted in runoff reduction in the southern and eastern Plateau regions. By contrast, more convective precipitation over the central TP was triggered under the warmer and moister condition and yielded more runoff; meanwhile, the solar dimming weakened lake evaporation. The two together with enhanced glacier melts contributed to the lake expansion in the central TP.
Climate change implications for the glaciers of the Hindu Kush, Karakoram and Himalayan region.
ABSTRACT The Hindu Kush, Karakoram, and Himalaya (HKH) region has a negative average glacial mass balance for the present day despite anomalous possible gains in the Karakoram. However, changes in climate over the 21st century may influence the mass balance across the HKH. This study uses regional climate modelling to analyse the implications of unmitigated climate change on precipitation, snowfall, air temperature and accumulated positive degree days for the Hindu Kush (HK), Karakoram (KK), Jammu-Kashmir (JK), Himachal Pradesh and West Nepal regions (HP), and East Nepal and Bhutan (NB). The analysis focuses on the climate drivers of change rather than the glaciological response. Presented is a complex regional pattern of climate change, with a possible increase in snowfall over the western HKH and decreases in the east. Accumulated degree days are less spatially variable than precipitation and show an increase in potential ablation in all regions combined with increases in the length of the seasonal melt period. From the projected change in regional climate the possible implications for future glacier mass balance are inferred. Overall, within the modelling framework used here the eastern Himalayan glaciers (Nepal-Bhutan) are the most vulnerable to climate change due to the decreased snowfall and increased ablation associated with warming. The eastern glaciers are therefore projected to decline over the 21st Century despite increasing precipitation. The western glaciers (Hindu Kush, Karakoram) are expected to decline at a slower rate over the 21st century in response to unmitigated climate compared to the glaciers of the east. Importantly, regional climate change is highly uncertain, especially in important cryospheric drivers such as snowfall timing and amounts, which are poorly constrained by observations. Data are available from the author on request.
We find evidence that black soot aerosols deposited on Tibetan glaciers have been a significant contributing factor to observed rapid glacier retreat. Reduced black soot emissions, in addition to reduced greenhouse gases, may be required to avoid demise of Himalayan glaciers and retain the benefits of glaciers for seasonal fresh water supplies.
Janes TJ, BushA B G.
The role of atmospheric dynamics and climate change on the possible fate of glaciers in the Karakoram.
Abstract High-resolution regional climate simulations for the Karakoram Mountain range in the greater Himalayas have been performed to investigate the atmospheric dynamics of this region, and their role in the Karakoram鈥檚 snowfall accumulation and possible glacial evolution through the next century. It has been found through a combination of field measurements and satellite observations that glaciers in this region appear to be reacting differently to contemporary climate change than those in other regions. This region has exhibited a relatively large number of either static or advancing glaciers while other glaciers in the central and eastern Himalayas, as well as around the world, are nearly all retreating. The amount of precipitation received in the Karakoram region depends on the interplay between two climate systems: the westerly winds flowing over the Mediterranean and Caspian Seas, and the South Asian monsoon winds (also referred to as the Indian monsoon) flowing over the Indian Ocean. This study extends the modeling time frame by performing time-slice calculations for the Karakoram region through the twenty-first century. Despite regionwide simulated temperature changes, the highly elevated regions of the Karakoram Mountain range experience positive climatic mass balance until the end of the modeling time period. This result arises from a strong positive correlation between climatic mass balance and simulated increases in regional precipitation, which outweighs the negative correlation between climatic mass balance and simulated increases in temperature. Also, the extreme elevations within the Karakoram allow regional alpine glaciers to benefit from a strong elevation-dependent signal simulated in net snowfall accumulation, and hence climatic mass balance.
<p>Despite the observed increase in global temperature, observed pan evaporation in many regions has been decreasing over the past 50 years, which is known as the "pan evaporation paradox". The "pan evaporation paradox" also exists in the Tibetan Plateau, where pan evaporation has decreased by 3.06 mm a<sup>-2</sup> (millimeter per annum). It is necessary to explain the mechanisms behind the observed decline in pan evaporation because the Tibetan Plateau strongly influences climatic and environmental changes in China, Asia and even in the Northern Hemisphere. In this paper, a derivation based approach has been used to quantitatively assess the contribution rate of climate factors to the observed pan evaporation trend across the Tibetan Plateau. The results showed that, provided the other factors remain constant, the increasing temperature should have led to a 2.73 mm a<sup>-2</sup> increase in pan evaporation annually, while change in wind speed, vapor pressure and solar radiation should have led to a decrease in pan evaporation by 2.81 mm a<sup>-2</sup>, 1.96 mm a<sup>-2</sup> and 1.11 mm a<sup>-2</sup> respectively from 1970 to 2005. The combined effects of the four climate variables have resulted in a 3.15 mm a<sup>-2</sup> decrease in pan evaporation, which is close to the observed pan evaporation trend with a relative error of 2.94%. A decrease in wind speed was the dominant factor for the decreasing pan evaporation, followed by an increasing vapor pressure and decreasing solar radiation, all of which offset the effect of increasing temperature across the Tibetan Plateau.</p>