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A large number of Himalayan glacier catchments are under the influence of humid climate with snowfall in winter (November-April) and South-West monsoon in summer (June–September) dominating the regional hydrology
. Such catchments are defined as "Himalayan catchment", where the glacier melt water contributes to the river flow during the period of annual high flows produced by the monsoon. Other two major glacio-hydrological regimes of the Himalaya are winter snow dominated Alpine catchments of the Kashmir and Karakoram region and cold-arid regions of the Ladakh mountain range. Factors influencing the river flow variations in a "Himalayan catchment" were studied in a micro scale glacier catchment in the Garhwal Himalaya, covering an area of 77.8 km2. Discharge data generated from three hydrometric stations established at different altitudes of the Din Gad stream during the summer ablation period of 1998, 1999, 2000, 2001, 2003 and 2004. These data has been analysed along with winter/summer precipitation, temperature and mass balance data of the Dokriani glacier to study the role of the glacier and precipitation in determining the runoff variations along the stream continuum from the glacier snout to 2360 m a.s.l. Study shows that the inter-annual runoff variations in a "Himalayan glacier catchment" is directly linked with the precipitation rather than mass balance changes of the glacier. Study suggest that warming induced initial increase of glacier degraded runoff and subsequent decline is a glaciers mass balance response and cannot be translated as river flow response in a "Himalayan catchment" as suggested by the IPCC, 2007. Study also suggest that the glacier runoff critically influence the headwater river flows during the years of low summer discharge and proposes that the "Himalayan catchment" could experience higher river flows and positive glacier mass balance regime together in association with strong monsoon. This paper intended to highlight the importance of creating credible knowledge on the Himalayan cryospheric processes to develop a global outlook on river flow response to cryospheric change and locally sustainable water resources management strategies.
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This study provides mapping and analysis of the maximum glacier extent during the "Little Ice Age" in Jotunheimen, Southern Norway, on a regional scale
. Remote sensing techniques were used to map the glacier area at the maximum of the "Little Ice Age" (mid 18th century AD). For validation of the mapping, interpretation of existing glaciochronological studies, analysis of geomorphological maps and our own field measurements using GPS have been applied. The flow length of the glaciers and other inventory data were determined by using a Geographical Information System and a digital elevation model. A total of 233 glaciers existed during the "Little Ice Age" maximum in Jotunheimen, comprising an overall glacier area of about 290 km2. Mean glacier flow length was calculated as about 1.6 km. Until AD 2003, the area shrank by about 35% and the mean flow length decreased by about 34%, compared with the maximum "Little Ice Age" extent.
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Sublimation plays a decisive role in the surface energy balance of tropical glaciers
. During the dry season low specific humidity and high surface roughness favour the direct transition from ice to vapour and drastically reduce the energy available for melting. However, field measurements are scarce and little is known about the performance of sublimation parametrisations in glacier mass balance and runoff models.
During 15 days in August 2005 sublimation was measured on the tongue of Glaciar Artesonraju (8 58 S, 77 38 W) in the Cordillera Blanca, Peru, using simple lysimeters. Indicating a strong dependence on surface roughness, daily totals of sublimation range from 1–3 kg m−2 for smooth to 2–5 kg m−2 for rough conditions.
Measured sublimation was related to characteristic surface roughness lengths for momentum (zm ) and for the scalar quantities of temperature and water vapour (zs ), using a process-based mass balance model. Input data were provided by automatic weather stations, situated on the glacier tongue at 4750 m ASL and 4810 m ASL, respectively. Under smooth conditions the combination zm =2.0 mm and zs =1.0 mm appeared to be most appropriate, for rough conditions zm =20.0 mm and zs =10.0 mm fitted best.
Extending the sublimation record from April 2004 to December 2005 with the process-based model confirms, that sublimation shows a clear seasonality. 60–90% of the energy available for ablation is consumed by sublimation in the dry season, but only 10–15% in the wet season. The findings are finally used to evaluate the parametrisation of sublimation in the lower-complexity mass balance model ITGG, which has the advantage of requiring precipitation and air temperature as only input data. It turns out that the implementation of mean wind speed is a possible improvement for the representation of sublimation in the ITGG model.
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Climate change is the number one threat to human development
. Yet progress towards limiting global warming to below 2°C has not been sufficient.
The global effort required to reduce emissions and support the poorest and most vulnerable people to adapt to unavoidable changes must be based on objective indicators of countries' historic responsibilities for causing the crisis, and their capabilities to confront it.
The Poznan climate talks must mark a turning point in international negotiations, switching from analysis and discussion to full negotiation mode. For the sake of people and the planet there is no more time to lose
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