Impact of a global temperature rise of 1.5 degrees Celsius on Asia’s glaciers

• Published in: Nature (London) Vol. 549; no. 7671; pp. 257 - 260
• Main Authors: Kraaijenbrink, P. D. A., Bierkens, M. F. P., Lutz, A. F., Immerzeel, W. W.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 14-09-2017; Nature Publishing Group
• Subjects: 704/106/125; 704/106/694/2786; 704/242; Anthropogenic climate changes; Anthropogenic factors; Climate; Climate change; Climate models; Cryosphere; Environmental impact; Environmental research; Extreme values; General circulation models; Glacier ice; Glaciers; Global temperatures; Global warming; Human influences; Humanities and Social Sciences; Intergovernmental Panel on Climate Change; letter; Mountains; multidisciplinary; Paris Agreement; Precipitation; Science; Surface-ice melting; Temperature; Temperature effects; Temperature rise; Water management; Water supply; Asia; Hindu Kush
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature23878

Models show that even if global temperature rise can be limited to 1.5 degrees Celsius, only about 65 per cent of glacier mass will remain in the high mountains of Asia by the end of this century, and if temperatures rise by more than this the effects will be much more extreme.
Climate target confronts glacier fate
The Paris Agreement advocates that humanity should consider limiting global warming to no more than 1.5 degrees Celsius (°C) above pre-industrial temperatures, well below the previously discussed threshold of 2 °C. The announcement sparked a surge of research to understand the practicality and implications of the lower limit. Here, Philip Kraaijenbrink and colleagues simulate the effect of warming on the glaciers in the high mountains of Asia and show that, in a world that warms by just 1.5 °C, about 65 per cent of glacier mass will remain by 2100. But keeping warming below the 1.5 °C threshold is an ambitious goal. At the other extreme, scenarios that include continued high rates of greenhouse gas production instead suggest that only about 35 per cent of mass will remain by 2100.
Glaciers in the high mountains of Asia (HMA) make a substantial contribution to the water supply of millions of people
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,
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, and they are retreating and losing mass as a result of anthropogenic climate change
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at similar rates to those seen elsewhere
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,
5
. In the Paris Agreement of 2015, 195 nations agreed on the aspiration to limit the level of global temperature rise to 1.5 degrees Celsius ( °C) above pre-industrial levels. However, it is not known what an increase of 1.5 °C would mean for the glaciers in HMA. Here we show that a global temperature rise of 1.5 °C will lead to a warming of 2.1 ± 0.1 °C in HMA, and that 64 ± 7 per cent of the present-day ice mass stored in the HMA glaciers will remain by the end of the century. The 1.5 °C goal is extremely ambitious and is projected by only a small number of climate models of the conservative IPCC’s Representative Concentration Pathway (RCP)2.6 ensemble. Projections for RCP4.5, RCP6.0 and RCP8.5 reveal that much of the glacier ice is likely to disappear, with projected mass losses of 49 ± 7 per cent, 51 ± 6 per cent and 64 ± 5 per cent, respectively, by the end of the century; these projections have potentially serious consequences for regional water management and mountain communities.