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The influences of human activity on regional climate over China have been widely reported and drawn great attention from both the scientific community and governments. This paper reviews the evidence of the anthropogenic influence on regional climate over China from the perspectives of surface air temperature (SAT), precipitation, droughts, and surface wind speed, based on studies published since 2018. The reviewed evidence indicates that human activities, including greenhouse gas and anthropogenic aerosol emissions, land use and cover change, urbanization, and anthropogenic heat release, have contributed to changes in the SAT trend and the likelihood of regional record-breaking extreme high/low temperature events over China. The anthropogenically forced SAT signal can be detected back to the 1870s in the southeastern Tibetan Plateau region. Although the anthropogenic signal of summer precipitation over China is detectable and anthropogenic forcing has contributed to an increased likelihood of regional record-breaking heavy/low precipitation events, the anthropogenic precipitation signal over China is relatively obscure. Moreover, human activities have also contributed to a decline in surface wind speed, weakening of monsoon precipitation, and an increase in the frequency of droughts and compound extreme climate/weather events over China in recent decades. This review can serve as a reference both for further understanding the causes of regional climate changes over China and for sound decision-making on regional climate mitigation and adaptation. Additionally, a few key or challenging scientific issues associated with the human influence on regional climate changes are discussed in the context of future research. [ABSTRACT FROM AUTHOR]

The Qinling Mountains, a key ecological zone of terrestrial ecosystem, has experienced a significant change of vegetation coverage in recent years. Based on MODIS-NDVI data, DEM data and meteorological data such as temperature, precipitation, sunshine, humidity and wind speed, this paper calculated the Fractional Vegetation Coverage (FVC) in Qinling Mountains, analyzed the background characteristics of the“pattern-process-trend”change, and explored the dual response mechanism of the vegetation coverage to climate change and human activities with trend analysis method, multiple regression method- residual method and PLS regression method. The results of the study showed that: First, the FVC in Qinling Mountains showed a significant increase trend at a growth rate of 2.77%/10 a during 2000-2015, with a very significant upward trend in the southern slope at a growth rate of 3.8%/10 a and a non-significant downward trend in the northern slope. In the space, FVC showed the pattern that is“high in the middle, low in the surroundings; high in the west, low in the east; high in the south-slope, low in the north-slope”. Second, the level of FVC in Qinling Mountains varied greatly, and the order of each FVC grade in area was Ⅴ, Ⅳ, Ⅲ, Ⅱ and Ⅰ, the area of Ⅰ and Ⅴ showing significant upward trend while the area of others showing decline trend. Third, the change of FVC at different altitudes was significantly different. There was a significant upward trend under 1 500 m and obvious downward trend at 2 600 m, while there was no obvious change at 1 500-2 600 m. With the increase of altitude, the FVC reached a maximum at 2 200 m. The FVC at 700-3 200 m was more than 0.7 and at 1 300- 2 700 m was more than 0.9, and values below 0.5 mainly appeared in high altitude area above 3 400 m. Forth, there were significant spatial differences in the response of vegetation coverage to climatic factors. The response of vegetation coverage to precipitation had time lag, with a lag of one month, while the response to temperature did not have time lag. Fifth, the role of human activities was increasing rapidly, with the growth rate of 2.10%/10 a. The positive effect of human activities on FVC mainly distributed in the eastern region, and the negative effect of human activities mainly distributed in the central and western regions. Finally, the FVC changes were the results of both climate change and human activities, and the impact factors from strong to weak are human activity, precipitation, temperature and potential evapotranspiration. [ABSTRACT FROM AUTHOR]

The changes of lake water resources record the impacts of climate change and human activities on the regional hydrological processes in the changing environment. Especially for inland areas with less precipitation, timely and accurate information on changes in lake water resources are recorded. Environmental evolution has an important reference value. With China’s largest desert freshwater lake-Hongjiannao Lake as an example, based on the 3S (RS, GIS, and GPS, which are remote sensing, global position system, geographic information system) technology, lake water surface area change was analyzed, which provided important scientific guidance for the restoration, protection and utilization of ecological and economic functions of Hongjiannao Lake. However, due to the different sources of data, the uneven technology, the discontinuous time series and the generally short time series, as well as the different monitoring phases, the result analysis on the change of water area of Hongjiannao Lake is quite different and systematic study and overall analysis of long time series of the entire river basin are lacking. Fifteen periods of both basic and RS data collected for Hongjiannao Lake, such as DRG, DLG, DOM, remote sensing images, and paper maps, were selected for analysis over a recent 60-year period (from 1957 to 2015), together with field annotation data and relevant attributes. All the data and images above have passed the geometric correction of digital elevation model data from Shaanxi Surveying and Mapping Archives and Geological Information Bureau of State Bureau of Surveying and Mapping, which have good quality. Different data can meet the high-precision registration requirements of water body information extraction in the study area. Among them, NDWI (normalized difference water index) with better extraction effect was used to extract water body information, which could restrain the vegetation soil while enhance the water body information. To analyze characteristics in spatio-temporal variations and identify trends of the change in lake water area over the period, we comprehensively utilized RS and GIS techniques and adopted spatial data processes, extracted and interpreted information, constructed a massive database, and conducted integrated management and analysis. We also explored major causes that triggered spatio-temporal variations of lake water area by combining climate change and anthropogenic factors from the same period. Results indicated that in a recent 60-year period, the area covered by water significantly changed in the study area. During 1957-1976, the water area continuously increased from 37.6 to 55.53 km2, and reached the maximum value over the entire record of study with increased amplitude of 47.69%. The growth rates in northern and southeastern areas of the lake were relatively fast, followed by other regions. During 1977-1999, the overall water area was stable, approximately 50 km2. During 2000-2015, water area showed a decreasing trend year by year, from 50.27 to 31.05 km2 with decreased amplitude of 38.23%, and all regions showed this shrinking trend except waters near Qibusu River in 2005, in which the reverse occurred and the water area slightly increased. In general, over the last 60 years, the revolution process of the water area of Hongjiannao Lake could be divided into 3 phases corresponding to the annual variability of water area: expanding period (1957-1976), stabilizing period (1977-1999), and shrinking period (2000-2015), showing an overall shrinking trend. The area of lakes and waters has experienced a dynamic trend of expansion-stabilization-atrophy in the recent 60 years, and has shown a significant atrophy situation since 1999 and a strong signal of ecological and hydrological deterioration, deserving attention. Trends in both warming and drying climate may be the major factors, which affect lake water area variation in both expanding and stabilizing periods, and the superimposition of these trends with anthropogenic effects (i.e. a water conservation project construction in the upper streams, coal mining, pavement construction around the lake, and water consumption for irrigation) may be the essential factor leading to water area variations during the shrinking period. [ABSTRACT FROM AUTHOR]

To commemorate 100 years since the birth of Professor Duzheng YE, this paper reviews the contribution of Ye and his research team to the development from climate to global change science in the past 30 or so years, including: (1) the role of climate change in global change; (2) the critical time scales and predictability of global change; (3) the sensitive regions of global change-transitional zones of climate and ecosystems; and (4) orderly human activities and adaptation to global change, with a focus on the development of a proactive strategy for adaptation to such change. [ABSTRACT FROM AUTHOR]