Created with special thanks to Profs. YAO Tandong (Third Pole Environment), MA Yaoming, Walter Immerzeel (Mountain Hydrology, Future Water) and Tobias Bolch (Mountain Cryosphere) as well as Dr. GONG Ping and Dr. YOU Chao.

 

In the world George R.R. Martin created in his series A Song of Ice and Fire, there is a wall made of mostly ice stretching across the northern border of the Seven Kingdoms[1]. “The Wall is not just ice and stone,” says Benjen Stark, the First Ranger of the Night's Watch, who guards the wall. “Ancient spells were carved into its foundation, strong magic to protect men from what lies beyond. And while it stands, the dead cannot pass.” In the world we live in, there is also a wall of ice and stone that has enabled millions to live with magic of its own. With numerous high-mountain glaciers, the Third Pole serves as an ecological buffer that has made the difference between life and death. 

 

Westeros, the main continent in Martin’s world, is warm in the South and cold in the North, but generally livable, a climate known to the Westerosi as the “long summer.” It is threatened by a long winter of unbearable cold and darkness beyond the wall. “Winter is coming” is the motto of House Stark, which lives closest to the wall. 

 

In our world, most human habitats, for now, are quite livable as well. Our climate is changing in the opposite direction, though. If there is a comparable “House of Climate Scientists,” then “warming is coming” would surely be its motto. As the wall for us non-Westerosi, the Third Pole has already felt the heat (see “Taking the Earth’s temperature”). While the wall in Westeros was built with ancient spells, the Third Pole was born out of the collision of the Indian and Eurasian plates. The ongoing uplift of the Tibetan Plateau, the center of the Third Pole, has changed, and continues to change the Asian landscape and river systems, which eventually is reflected in the local and global climates[2]. 

 

The rotation of the earth has generated planetary winds, which, to a large extent, shape how our planet looks. For example, the plenary winds in the subtropical region drive air to the land; as the air heats up going downward, it is less likely for water vapor to condense, or, in other words, to rain, thus forming vast deserts across North Africa and West Asia. However, at almost the same latitude, you will also find the Yangtze River and the Nile, as well as the cities of New Delhi, Kathmandu, Chongqing and Hangzhou, which are known for their humidity. Why? The “Wall” happened. The Third Pole, with its sheer height, has stopped plenary winds from drying its surroundings. Here is its magic spell: The sun heats the Third Pole with radiation, which gives rise to warm air at high altitudes. As the warmer air goes up, the vacancy has to be filled with air drawn from its lower surroundings. In its climb up to the Third Pole, the air gets cooled and sometimes condenses. And then it rains. The rainfall feeds into rivers and lakes, which give birth to various human civilizations[3].

 

Scientists have found that land surface processes and precipitation at the Third Pole can impact downstream weather and climate change. Third Pole heating has profound impacts on downstream rainstorms over the Yangtze River Basin through atmospheric processes [4].

 

 

The wall in Martin’s world shields life from the dreadful army of the Night King. The Third Pole, on the other hand, sustains life through its invaluable water resources. 

 

An international team of 32 scientists ranked 78 mountain glacier-based water systems all over the world in order of their importance to adjacent lowland communities, and evaluated their vulnerability to future environmental and socioeconomic changes. The Third Pole, or the Asian water towers, are ranked among the world’s most important and most vulnerable water towers [5, 6]. Glaciers are retreating, permafrost is degrading, and snow cover days are decreasing at the Third Pole. Glaciers, permafrost, lakes and snow cover are key freshwater resources, and industry, agriculture, and hydroelectric power generation downstream all rely on timely and sufficient delivery of water[7]. Changes in glaciers, permafrost and snow cover may increase the risk of natural hazards. New types of glacier-related disasters are occurring on the Third Pole. On July 17 and Sept. 21, 2016, two massive ice collapses occurred in the Aru Range, Ngari, in the western Third Pole region, causing nine human casualties and the loss of hundreds of livestock. On Oct. 17 and Oct. 29, 2018, glacier collapse caused debris flow and blocked the Yarlung Zambo River in the Sedongpu Valley of the southeastern Third Pole region. The fact that both continental and maritime glaciers have experienced such a catastrophic collapse seems to suggest that glaciers on the Tibetan Plateau may increasingly become unstable due to global warming[8].

 

 

Asian Water Towers water towers[6]

 

Glacier melt water can increase river runoff in the short run; however, as glaciers recede further, the risk of exhausting existing glaciers also looms. It is estimated that the Third Pole will see “peak water” on average between 2030 and 2050, when annual glacier runoff will reach a maximum, and will only decrease after that [9-11]. In some places, the peak water may even arrive earlier than 2030[11]. 

 

 

Estimated Peak Water for different basins across the Third Pole[11]

 

“We need to monitor Third Pole cryosphere changes closely so as to understand their impacts on water resources,” said Prof. YAO Tandong, co-chair of Third Pole Environment (TPE). “It is also critical for us to develop adaption strategies, not just at the regional or national level, but at the basin scale involving all riparian countries, in order to take account of and balance the demand for water from all the parties in the large watersheds.”

 

Ice and fire are the formative powers of Martin’s story, represented by two ancient houses, the Starks and the Targaryens. The center of the ice-fire struggle is Jon Snow, child of a Stark mother and a Targaryen father. Then substitute levoglucosan for Jon Snow in real life. Levoglucosan is a spin-off chemical typical of fire, and can be found in ice cores as a result of combustion residues reaching glaciers via wind.

   

 

Jon Snow, as everyone agrees, knows nothing. But levoglucosans, specific fire tracers that can reveal past fire activities, surely know a lot. According to Dr. YOU Chao, a scientist at the Institute of Tibetan Plateau, Chinese Academy of Sciences, levoglucosans in the Himalayas have revealed a rapid increase in wildfire across the Third Pole in the beginning of this century [12].

 

 Wildfire spots captured by satellite image from May 5-12, 2018

 

In Martin’s the world, the Starks and the Targaryens forged an alliance under Jon Snow to jointly defend the wall and Westeros behind it, a tricky union that would end in tragedy once the fragile balance was broken. Such ice-fire entanglement is also present at the Third Pole. Dr. You’s research shows that more wildfires, and consequently more fire-related greenhouse gases and smoke aerosols, will threaten regional environmental and public health, and could play a role in Himalayan glacier melting during the pre-monsoon season [13]. 

 

The wall in Martin’s world is not impenetrable, nor is the Third Pole. Toxic substances released by industry and agriculture, as well as persistent organic pollutants (POPs) in South Asia have been travelling across the Himalayas to reach the Third Pole. “We know the Third Pole serves as a barrier to the atmospheric transport of POPs, but our question is: How effective is it?” said Dr. GONG Ping from the Institute of Tibetan Plateau Research, Chinese Academy of Sciences (ITPCAS). Dr. Gong and his team found that, for now, the wall seems to work reasonably well, as more than 90% of POPs are trapped along the slopes of the Himalayas due to rainfall scavenging and foliage absorption. The rest that remain in the air are transported through mountain valleys and ridges [14].

 

In Martin’s world, Jon Snow and his people fight against a long-feared winter brought by the evil Night King and his Army of the Dead. We also have our share of worries. The difference is, instead of a Night King, global warming is the one threatening to kill and destroy our world. Lord Commander of the Night’s Watch Jeor Mormont once said, “The wall was made to guard the realms of men . . . and not against other men. Too many years . . . too many hundreds and thousands of years, we lost sight of the true enemy.” The commander’s wisdom still rings true in our world today. 

 

References：

 

1. Martin, G.R., A song of ice and fire. 2011: Bantam books New York.

2. Yao, T., et al., Multispherical interactions and their effects on the Tibetan Plateau's earth system: a review of the recent researches. 2015. 2(4): p. 468-488.

3. Wu, G., et al., Review of the impact of the Tibetan Plateau sensible heat driven air-pump on the Asian summer monsoon. Chinese J. Atmos. Sci, 2018. 42: p. 488-504.

4. Fu, Y., et al., Land surface processes and summer cloud-precipitation characteristics in the Tibetan Plateau and their effects on downstream weather: a review and perspective. National Science Review, 2020.

5. Immerzeel, W.W., et al., Importance and vulnerability of the world’s water towers. Nature, 2020. 577(7790): p. 364-369.

6. Immerzeel, W.W., L.P. Van Beek, and M.F. Bierkens, Climate change will affect the Asian water towers. Science, 2010. 328(5984): p. 1382-1385.

7. Bolch, T., et al., Status and change of the cryosphere in the Extended Hindu Kush Himalaya Region, in The Hindu Kush Himalaya Assessment. 2019, Springer. p. 209-255.

8. Yao, T., et al., Recent Third Pole’s rapid warming accompanies cryospheric melt and water cycle intensification and interactions between monsoon and environment: Multidisciplinary approach with observations, modeling, and analysis. Bulletin of the American Meteorological society, 2019. 100(3): p. 423-444.

9. Huss, M. and R. Hock, Global-scale hydrological response to future glacier mass loss. Nature Climate Change, 2018. 8(2): p. 135-140.

10. Tandong Yao, Y.Z., Ninglian Wang, Lin Zhao, Tao Che, Guangjian Wu, Qiuhong Tang, Walter Immerzeel, Tobias Bolch, Francesca Pellicciotti, Xin Li, Wei Yang, Jing Gao, Weicai Wang and Baiqing Xu, Third Pole climate warming and cryosphere system changes. WMO Bulletin, 2020. 69（1）.

11. Rounce, D.R., R. Hock, and D.J.F.i.E.S. Shean, Glacier mass change in high mountain Asia through 2100 using the open-source Python Glacier Evolution Model (PyGEM). 2020. 7: p. 331.

12. You, C., T. Yao, and C.J.J.o.G.R.A. Xu, Recent increases in wildfires in the Himalayas and surrounding regions detected in central Tibetan ice core records. 2018. 123(6): p. 3285-3291.

13. You, C., T. Yao, and C.J.S.B. Xu, Environmental significance of levoglucosan records in a central Tibetan ice core. 2019. 64(2): p. 122-127.

14. Gong, P., et al., Trans-Himalayan Transport of Organochlorine Compounds: Three-Year Observations and Model-Based Flux Estimation. Environmental science technology, 2019. 53(12): p. 6773-6783.