Potential impacts of climate change on vegetation dynamics in Central Asia

Abstract

Observations indicate that although average temperatures in Central Asia showed almost no increases from 1997 to 2013, they have been in a state of high variability. Despite the lack of a clear increasing trend, this 15 year period is still the hottest in nearly half a century. Precipitation in Central Asia remained relatively stable from 1960 to 1986 and then showed a sharp increase in 1987. Since the beginning of the 21st century, however, the increasing rate of precipitation has diminished. Dramatic changes in meteorological conditions could potentially have a strong impact on the region's natural ecosystems, as some significant changes have already occurred. Specifically, the normalized difference vegetation index (NDVI) of natural vegetation in Central Asia during 1982–2013 exhibited an increasing trend at a rate of 0.004 per decade prior to 1998, after which the trends reversed, and the NDVI decreased at a rate of 0.003 per decade. Moreover, our results indicate that shrub cover and patch size exhibited a significant increase in 2000–2013 compared to the 1980s–1990s, including shrub encroachment on grasslands. Over the past 10 years, 8% of grassland has converted to shrubland. Precipitation increased in the 1990s, providing favorable conditions for vegetation growth, but precipitation slightly reduced at the end of the 2000s. Meanwhile, warming intensified 0.93°C since 1997 compared to the average value in 1960–1997, causing less moisture to be available for vegetation growth in Central Asia.

Spatiotemporal Variation of Snow Cover in Tianshan Mountains, Central Asia, Based on Cloud-Free MODIS Fractional Snow Cover Product, 2001–2015

“…Under the context of global warming, and the state of high variability in temperature of the Tianshan Mountains since 1998 [44,48], the cryosphere of the Tianshan Mountains has been changing rapidly [10][11][12][13]. A number of studies have investigated snow cover change in Tianshan Mountains of china, using meteorological stations data [17][18][19]21]; one general conclusion of them is that snowfall and snow cover depth in Tianshan Mountains of China show an increasing tendency in the last decades of the 20th century.…”

“…We also examine the snow cover variations from different subregions (Central Tianshan, Western Tianshan, Northern Tianshan and Eastern Tianshan) of the Tianshan Mountains. The specific aims are to examine the snow cover variations in the Tianshan Mountains during the state of high variability in temperature of the Tianshan Mountains since 1998 [44,48] and to address the possible cause for the snow cover changes from the perspective of climate factors.…”

Dynamic changes in terrestrial net primary production and their effects on evapotranspiration

“…This may be related to the expansion of woody vegetation over the past 15 years. In the Arctic tundra (Hughes et al, 2006) and lower latitudes in arid environments (Chen et al, 2014;Li et al, 2015), experimental studies provided clear evidence that climate warming is sufficient to account for the expansion of shrubs. Changes in vegetation albedo and emissivity exert feedback on climate, which is especially obvious in ET (Field et al, 2007).…”

Large Hydrological Processes Changes in the Transboundary Rivers of Central Asia

“…However, due to the deleterious impacts of global warming, the vulnerability of the region's water systems and resources is steadily increasing. In fact, the dwindling of water resources caused by changes in global climate will likely lead to future conflicts between regions and countries in Central Asia when water demands outstrip supply in the burgeoning oasis economy and desert ecology (Chen et al, ; Li et al, ).…”