It won't take more than a few decades for many Himalayan glaciers to disappear, leaving the Ganga, Indus and Brahmaputra as seasonal rivers.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/melting-glaciers
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/deccan-herald
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/himalaya
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/climate-change
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/climate-impacts
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/glacial-melt
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/unep
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/india