The temperature and precipitation in the Tibetan Plateau (hereinafter referred to as the ‘TP’) increase as a whole, and the vegetation of the plateau has changed significantly under the influence of climate change. This paper summarizes the research progress on plateau climate change and its impact on plateau vegetation coverage and normalized difference vegetation index (NDVI), phenology, net primary productivity (NPP), biomass carbon pool, plant diversity and so on, and the future directions of research are discussed and expected. The main conclusions are as follows: (1) In recent 60 years, the annual average temperature increased significantly with an average increase of 0.37 ℃ per 10 years, and the annual precipitation increased with an average increase of 10.40 mm per 10 years in the TP. The warm and dry trend of climate in the southeast of the TP and the warm and humid trend of climate in the northwest of the TP were obvious. (2) Under the background of overall improvement, the vegetation coverage and NDVI degraded in local regions of the TP. The improved area accounted for 67.7%-75.0% of the plateau total area, and they mainly distributed in the central and eastern regions. (3) Under of the influence of climate change, the green returning period of vegetation in the plateau advanced, the dry and yellow period postponed, and the growth period prolonged on the whole. However, there is a great debate on the green returning period of plateau vegetation in advance after 2000. (4) NPP of plateau vegetation increased significantly as a whole, while the increasing rate of NPP slowed down after 2000. NPP of vegetation increased significantly in southern Qilian Mountains and alpine meadows of northern Nianqing Tanggula Mountains, while it decreased in northern Tibetan Plateau, ‘one river, two rivers’ and the central and western regions of Tibet three river sources. (5) The biomass carbon pool of the plateau vegetation showed an increasing trend, which was carbon sink in general, and the spatial heterogeneity was obvious. The biomass carbon of alpine meadow and steppe increased significantly, while that of other grassland increased slightly, and even decreased in some areas. (6) The plant diversity in the plateau has changed significantly. Although the research results were different, there is no doubt that the climate change has affected significantly on species composition and plant diversity of alpine grassland community. It is suggested to strengthen data networking observation comparison and multi-scale effect research, deepen internal mechanism research and multi-factor comprehensive and quantitative analysis, strengthen sharing mechanism and improve the coping ability to climate change in the future, so as to promote ecological protection and high-quality development of the plateau.

Based on MCI (meteorological drought composite index) at 103 stations of Sichuan Basin from 1961 to 2018, the temporal and spatial variation characteristics of extreme summer drought days (ESDD) in quasi-biennial period and its possible causes in Sichuan Basin were analyzed by using MTM-SVD (multi taper method and singular value decomposition) and EOF (empirical orthography function), etc. The results show that the main mode of ESDD in Sichuan Basin appeared the same variation in the whole region, the interannual and interdecadal variation characteristics were obvious, and the interannual oscillation periods with 2.3-2.5 a were the most significant in recent 58 years. The typical cycle with quasi-biennial period showed the more or less ESDD oscillated alternatively in Sichuan Basin, and the large value center appeared in the middle of the basin, which was basically consistent with the main mode of EOF. However, the quasi-biennial period signal of ESDD in Sichuan Basin did not always exist from 1961 to 2018, and the signal was the strongest from the late 1960s to the early 1980s. In the first year of typical cycle with quasi-biennial period, the locations of the western Pacific subtropical high ridge line and the subtropical westerly jet axis were to the north, Sichuan Basin located in the west of vapor abnormal transport belt from the south of Japan to the west of South China, and there was abnormal divergence, which wasn’t conducive to the formation of precipitation, further led to more ESDD. The anomaly distribution of atmospheric circulation in the second year was opposite to that in the first year, and ESDD was less.

In order to explore the relationship between natural pasture growth and meteorological conditions under the background of global warming in the ecological function area of northern shore of the Qinghai Lake, the influence of hydrothermal conditions on returning green date, growth height and yield of pasture were analyzed systematically based on meteorological and pasture observation data from 1997 to 2018. The results are as follows: (1) The influence of temperature on returning green date of pasture was significant in northern shore of the Qinghai Lake. The returning green date of pasture had significantly positive correlation with the first day of temperature higher than 0 ℃ and 3 ℃, the correlation coefficients were 0.590 and 0.567, respectively. (2) The growth rate of pasture had significant difference at different stages of growth, and the growth of pasture was the most vigorous from late June to mid-August. (3) The yield of pasture presented a significant ‘ladder’ variation characteristic in northern shore of the Qinghai Lake, and the average yield from 2010 to 2018 was 88% higher than that from 1997 to 2009. (4) The ≥0 ℃ accumulative temperature and precipitation during the growth of pasture presented an increasing trend in northern shore of the Qinghai Lake from 1997 to 2018, while the sunshine duration decreased, the warm and humid change characteristics were obvious, and the accumulative temperature of ≥0 ℃ during the growth of pasture was the key factor for the formation of pasture yield.