Chinese Journal of Nature

To the top of the Earth: Climate and environmental changes in Mt. Qomolangma region during past 60 years#br#

KANG Shichang, ZHANG Yulan, ZHANG Qianggong

2020, 42(5): 355-363. doi:10.3969/j.issn.0253-9608.2020.05.001

Asbtract ( 283 )

PDF (4362KB) ( 355 )

Related Articles | Metrics

Mt. Qomolangma is the highest mountain in the world and the hot spot of studies on global climate and environmental change. Since the late 1950s, several scientific expeditions have been carried out in the Mt. Qomolangma region, and one in situ observational research station has been established. During the past 60 years, the climate has been warming continuously in the
Mt. Qomolangma region, with the similar magnitude of temperature warming over the whole Tibetan Plateau. However, the trend
of precipitation was not significant. Mt. Qomolangma region is concentrated with glaciers, which have been experiencing largely
retreated. Consequently, the area of glacial-fed lakes expanded rapidly and the runoff increased, indicating the response of glaciers
and hydrological processes to global warming. Under the impact of climate warming, the vegetation in the Mt. Qomolangma region
has a tendency to become green. Since the industrial revolution, the Mt. Qomolangma region has been affected by the transboundary atmospheric pollutants, which has also highlighted the potential risk of secondary release of pollutants due to glacier melting.

Mercury in cryosphere of the Tibetan Plateau and its environmental significance

SUN Shiwei, KANG Shichang, ZHANG Qianggong, GUO Junming

2020, 42(5): 364-372. doi:10.3969/j.issn.0253-9608.2020.05.002

Asbtract ( 667 )

PDF (3152KB) ( 348 )

Related Articles | Metrics

Under the context of global warming, the environmental effects triggered by cryospheric changes have been a hot topic of global concern. The cryosphere on the Tibetan Plateau (TP) are undergoing significant retreat, which can accelerate the release of accumulated pollutants stored in the cryosphere, and therefore impact on ecosystems and biological health adversely. Mercury (Hg) is recognized as a global pollutant. Great progress has been made in the knowledge of historical records, concentrations levels and spatiotemporal distribution of Hg in typical environmental components of the TP cryospheric region (e.g., glacier, permafrost soils, water bodies and atmosphere). However, there is a lack of knowledge on potentially important Hg output pathways in the cryospheric region as well as their environmental effects, including the downstream transport of Hg from glacier, the release of Hg stored in permafrost soils during permafrost thawing and land-air Hg exchange dynamics. Studies on Hg in the TP cryospheric regions not only enrich our understanding of Hg cycles in the cryosphere, but provide basic theoretical basis for assessing the potential environmental risks of Hg to the TP fragile ecosystems as well as the environmental effects caused by cryospheric changes.

Study of air pollutants in the inland Tibetan Plateau (Nam Co Station)

YIN Xiufeng, KANG Shichang, ZHANG Qianggong, ZHANG Guoshuai

2020, 42(5): 373-378. doi:10.3969/j.issn.0253-9608.2020.05.003

Asbtract ( 807 )

PDF (1243KB) ( 403 )

Related Articles | Metrics

The Tibetan Plateau located in the southwest of China with its high elevation (average height over 4 000 m) and special geographical location. The Tibetan Plateau is a natural laboratory for atmospheric pollution research because of its relatively pristine environment and clean air due to its low emission of atmospheric pollutants. Nam Co Station, located in the inland Tibetan Plateau, is a typical atmospheric background station in the Northern Hemisphere. The Himalayas separate the Tibetan Plateau from the South Asia which is heavily polluted. Air pollutants released from South Asia can be transported though the Himalayas to the inland Tibetan Plateau by the transport of air mass. The Indian summer monsoon and westerly circulation played important roles in the long-range transport of atmospheric pollutants and has different mechanisms for different atmospheric pollutants. Researchers have conducted measurements of multiple air pollutants at the Nam Co Station in the inland Tibetan Plateau and obtained a series of results, which greatly promoted the scientific research on air pollution on the plateau and provided a scientific basis for China’s international environmental negotiations.

The environmental significance and research progress of atmospheric particulatebound mercury on the Tibetan Plateau#br#

GUO Junming, KANG Shichang, SUN Shiwei, NI Dingming

2020, 42(5): 379-385. doi:10.3969/j.issn.0253-9608.2020.05.004

Asbtract ( 142 )

PDF (986KB) ( 97 )

Related Articles | Metrics

Mercury (Hg) is a global pollutant because the atmospheric Hg can be transported globally and deposited into aquatic and terrestrial environments even in remote regions. Atmospheric particulate-bound mercury (PBM) plays a critical role in Hg deposition on the Tibetan Plateau. The importance of atmospheric PBM in Hg biogeochemical cycling on the Tibetan Plateau and research process was introduced in this article. Supported by the second Tibetan Plateau scientific expedition and research program, transboundary transport of atmospheric PBM and its potential environmental effect will be profoundly studied. These results are expected to provide valuable and fundamental scientific basis for the regional environmental protection.

Thermokarst terrains change landscape and earth surface processes

MU Cuicui

2020, 42(5): 386-392. doi:10.3969/j.issn.0253-9608.2020.05.005

Asbtract ( 1039 )

PDF (2061KB) ( 456 )

Related Articles | Metrics

Permafrost, a product of cold climate, can be degraded by climate warming. Permafrost thaws lead to the melting of ground ice and the water subsequent drain away, this process removes the support of surface layer, and thus leads to thermokarst terrains including thaw slump, ground subsidence. Thermokarst terrains not only affect infrastructure engineering, they can also deteriorate vegetation growth and deteriorate ecosystem. The ground subsidence can further gradually form thermokarst lake. Thermokarst terrains directly change landforms, and they also have great effects on hydrology, as well as carbon and nitrogen cycle. The topic of thermokarst development and its impacts have created many concerns in the permafrost environmental science. The quantitative assessment of effects of thermokarst terrains on carbon cycle is a fundamental step towards to understanding the response of permafrost and its feedback to climate change.

Carbonaceous components in snow and ice in the Third Pole region

ZHANG Yulan, LUO Xi, KANG Shichang, GAO Tanguang, HU Zhaofu

2020, 42(5): 393-400. doi:10.3969/j.issn.0253-9608.2020.05.006

Asbtract ( 560 )

PDF (3589KB) ( 395 )

Related Articles | Metrics

Carbonaceous components (e.g., black carbon (BC), organic carbon (OC)) play an important role on the global climate change and enhancing the glacier melt, which has triggered out a lot of interest and related studies. Based on the recent research of this topic, we reviewed the spatial and temporal characteristics of carbonaceous components in snow and ice in the Third Pole region. The results indicated those BC and OC concentrations in aged snow (or firn ice) showed much higher than that in snowpit and fresh snow, which enhanced our understanding on the carbonaceous component in different snow types in one entire glacier. Isotopic signature of BC in snowpit revealed that BC deposited on glaciers in the northern Tibetan Plateau mainly originated from anthropogenic emissions. However, in the central plateau, BC from biomass burning combustion contributed largely to the BC deposition on glaciers. In Himalayas, equal contributions from fossil fuel and biomass combustion to BC in snowpit were found. Radiative forcing caused by BC can reach to hundreds of W·m-2, further accelerating the glacier melting and reducing snow cover duration days. In the future, studies on the sources of carbonaceous components and their impact on the radiative forcing should be enhanced. These results will be served as a valuable scientific basis for the forecasting contributions of carbonaceous components to glacier melting under climate change.

Melting Himalayan glaciers impact the regional eco-environment

ZHANG Qianggong

2020, 42(5): 401-406. doi:10.3969/j.issn.0253-9608.2020.05.007

Asbtract ( 690 )

PDF (3269KB) ( 461 )

Related Articles | Metrics

The Himalayas, world’s highest mountain range, is one of the most mountain glacier-concentrated regions, and acts as an important water source for Asian countries. In the context of global warming, Himalayan glaciers have been undergoing accelerated melting, the glacier mass loss rate in the early 21st century approximately doubled to that in the late 20th century. Rapid rising temperature is the major reason for the glacier loss, additionally, relatively stable trend in precipitation and elevated emisison of atmospheric pollutants such as black carbon contributed to the fast wastage of glaciers. Melting Himalayan glaciers will change the hydrology of glacial-fed rivers, increase the numbers and areas of glacier lakes and enhance the related risks of glacier outburst floods. Besides, melting glaciers can influence the water chemistry and environment and thereby result in far-reaching impacts on local and distant eco-environmental systems and human health. The Himalayan glaciers are predicted to shrink in the future under the warming climate. We suggest promoting scientific monitoring and research, fostering regional cooperation, and implementing coordinated environmental protection among regional countries. These are fundamental measures to help forming a sustainable Himalayan mountain environment and society in the future.

The changes and impacts of snow cover in the Third Pole and the Arctic

ZHONG Xinyue, KANG Shichang, SHI Yanmei

2020, 42(5): 407-412. doi:10.3969/j.issn.0253-9608.2020.05.008

Asbtract ( 499 )

PDF (969KB) ( 257 )

Related Articles | Metrics

There is a significant change of snow cover under global warming. More and more studies have focused on the variations in snow cover in the Third Pole (the Tibetan Plateau) and the Arctic because they are the typical distribution areas at high elevation (the Third Pole) and high latitude (the Arctic). Over the past 60 years, the trends of snow cover extent and duration have decreased significantly in the Third Pole and the Arctic, while there was a spatial inhomogeneity of change in snow depth. The change in snow cover is closely related to climatic conditions, atmospheric circulation, and the light-absorbing impurities. Snow cover also has an important feedback on climate, hydrological, ecological and human systems. The resolution of snow cover research would provide basic data and support for the regional economic and socially sustainable development.

Studies of the iron biogeochemical cycle in snow and ice from the three poles

DU Zhiheng, XIAO Cunde, ZHANG Zhen

2020, 42(5): 413-420. doi:10.3969/j.issn.0253-9608.2020.05.009

Asbtract ( 130 )

PDF (2187KB) ( 171 )

Related Articles | Metrics

The bioavailable iron could control the marine productivity by regulating the phytoplankton growth, which influences the carbon exchanges between sea and air, and ultimately regulates the marine ecosystem and global climate change. The terrestrial bioavailable iron is deposited into the cryosphere (including glaciers, ice sheets, permafrost, sea ice and icebergs) by the atmospheric dry and wet depositions, and then stored on the earth surface as solid state. As a result of global warming, the retreat of main components of the cryosphere will release bioavailable iron into the surface system of earth at a global scale. Preliminary studies on the iron biogeochemical cycle have been made in the cryosphere area of the three poles (Antarctica, Arctic and Qinghai-Tibet Plateau) since 2000. Recent studies in the Greenland and Antarctica ice sheets have demonstrated that the bioavailable iron released by ice sheet melting could regulate the marine productivity. We introduce the historical progress of the iron hypothesis, and summarize its research achievements in cryosphere science, and propose research directions that may be broken through in the future.

Permafrost degradation will be the next “The day after tomorrow”?

GAO Tanguang

2020, 42(5): 421-424. doi:10.3969/j.issn.0253-9608.2020.05.010

Asbtract ( 605 )

PDF (1301KB) ( 179 )

Related Articles | Metrics

Climate system is likely to collapse when such climate factor getting a tipping point under global warming, resulting in the consequences similar to the disaster film of “The day after tomorrow”. Permafrost degradation is considered as an important abrupt climate factor in the climate system. In the context of global warming, permafrost is rapidly deteriorating and will release a huge amount of carbon. Especially the emergence of permafrost thermokarst, combined with other climate tipping point factor, may reach the threshold of planetary boundary of the earth system within the IPCC target of 2 ℃, which will have an irreversible impact on the climate system.

Permafrost degradation has important effects on climate and human society

WU Xiaodong, WU Tonghua

2020, 42(5): 425-431. doi:10.3969/j.issn.0253-9608.2020.05.011

Asbtract ( 1936 )

PDF (2561KB) ( 1013 )

Related Articles | Metrics

Permafrost is mainly distributed in high latitude and high-altitude areas, most people know little about it, while permafrost covers vast areas accounting for about a quarter of the land area of the Northern Hemisphere. As a product of cold climate, permafrost is sensitive to climate change, and global warming has led to the wide permafrost degradation in the world. The permafrost degradation can also have important effects on ecosystem changes, hydrological process, and many important infrastructures, and also have feedback effects on climate. Nowadays, many studies have been conducted in the permafrost both in the Arctic and in the Qinghai Tibet Plateau, while there are still many scientific questions need to be resolved. For better understanding of the future climate change, as well as design and implement of sustainable development approaches, more attentions should be paid on the permafrost change and its impact.

Table of Content