Climate Change and Cryosphere

发布时间:2016-12-30 16:13:11 点击次数:1186

On the evening of December 12, 2016, Professor Qin Dahe, member of Chinese Academy of Sciences as well as the Third World Academy of Sciences, addressed a speech titled “climate change and cryosphere” at the invitation of Peking University Institute of Ocean Research.

As the first Chinese who went across the Antarctica continent, Professor Qin is the pioneer of Chinese glaciology and has made great contribution to the development of cryosphere research in China. In this report, he mainly introduced the IPCC assessment reports, the concept of cryosphere and the effects of global climate change on marine system, etc.

Global warming has become an unneglectable issue nowadays. In order to assess the science related to climate change, especially to provide policymakers with regular assessments of the scientific basis of climate change, its impacts and future risks, and options for adaptation and mitigation, the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) set up a government agency - the UN's Intergovernmental Panel on Climate Change (IPCC) in 1988.

The IPCC work is shared among three Working Groups. The IPCC Working Group I (WG I) is responsible for assessing the physical scientific aspects of the climate system and climate change, in the process of which the researchers need to make a careful observation of the atmosphere, hydrosphere, lithosphere, cryosphere and biosphere, and make use of climate models to predict future climate change under different scenarios. The IPCC Working Group II is responsible for assessing the impact and risk of the climate change. The IPCC Working Group III (WG III) assesses options for mitigating climate change through limiting or preventing greenhouse gas emissions and enhancing activities that remove them from the atmosphere. As a Chinese scientist regularly involved in the making process of the IPCC assessment report, Professor Qin gave a brief introduction of the main characteristics and the latest knowledge regarding the previous assessment reports. In terms of the latest observational evidence present in these reports, the fact of global warming is proved to be indisputable. In the fifth assessment report, according to the observation results from 1880 to 2012, the global average surface temperature increased by 0.85 ℃; between 1951 and 2012, the global average surface temperature rose 0.12 ℃ every 10 years. As the latest assessment, the IPCC's fifth assessment report conveys three key messages: (1) human influence on the climate system is clear and growing; (2) the more human activities disrupt the climate, the greater the risks of severe, pervasive and irreversible impacts for people and ecosystems, and long-lasting changes in all components of the climate system; (3) we have the means to limit climate change and its risks, with many solutions that allow for continued economic and human development. The trend of global warming is so obviously that the evidence of its negative impacts on nature and human’s social life could be found widely, including the rising sea levels, the heat waves, the ocean acidification, the cryosphere retreat, the frequent extreme events, etc. (IPCC, 2014).

Professor Qin then introduced the cryosphere science research from the perspectives of its concept, classification and the relationship with the various spheres of the earth. The cryosphere is the collective term for the components of the Earth system that contain a substantial fraction of water in the frozen state, which comprises several components: snow, river and lake ice; sea ice; ice sheets, ice shelves, glaciers and ice caps; and frozen ground which exist, both on land and beneath the oceans. The distribution of the components is quite uneven, mainly in middle and high latitudes. According to their geographical distribution, the cryosphere components are divided into three classifications: land cryosphere, marine cryosphere and cryosphere atmosphere.

The cryosphere science focuses on the study of cryosphere components’ formation process and mechanism, changes and interaction with other earth’s spheres in the climate system. Professor Qin pointed out that all scientific problems are integrated, as a result of which the scientists and researchers need to attach importance to cross disciplines. The statistical evidence shows cryosphere plays an extremely important role in the history of the earth's climate change, especially in the quaternary glaciation and interglacial period. As its components are inherently sensitive to temperature change over a wide range of time scales, the cryosphere is a natural integrator of climate variability and provides some of the most visible signatures of climate change. Moreover, changes in each component of the cryosphere have a significant and lasting impact on physical, biological and social systems. For example, the melting and retreating of ice sheets and glaciers will exert great influence over sea level rise and habitat loss, and decline in snow cover and sea ice will tend to amplify regional warming through snow and ice-albedo feedback effects. Therefore, the study of cryosphere is very necessary and important. In addition, along with the advancement of global climate change science, cryosphere science has become an integrated science that combines natural science and economic and social sustainable development.

Professor Qin then introduced the impacts of climate change for marine environment and human production activity with the latest research data. For the marine system, the global warming results in sea level rise and ocean acidification, the change in the upper ocean heat content and marine ecosystem, etc. For human activity, the change in ocean would exercise influence on habitat environment, fishery industries, navigational trade, etc. Professor Qin repeatedly mentioned “the thin blue line” concept, which refers to the coastal area that threatened by sea level rise. “If human do not take immediate measures to control the acceleration of global warming, many coastal areas would be in jeopardy,” he stressed.

Professor Qin’s report is so attractive that it not only provided a wealth of knowledge and wisdom, but also showed the proper academic style and rigorous researching attitude, which is believed to inspire the audience to embark on creative study and research in the following days.