Characteristics of climate change in southwest China karst region and their potential environmental impacts

Global warming, due to the enhanced greenhouse effect, is likely to have significant effect on the hydrological cycle, which would result in more evaporation, more precipitation, and uneven distribution of precipitation around the globe. Some parts of the world may see significant reduction in precipitation, or major alterations in the timing of wet and dry seasons, and increases in both floods and droughts. In China, a warming trend has been observed across the mainland region during the past 50 years, with an increasing temperature of about 0.2-0.3 A degrees C/10 year in northern and less than 0.1 A degrees C/10 year in southern China. To understand the characteristics of climate change, this study has conducted statistical analysis on climate parameters from 12 representative meteorological stations in southwest China karst region. The non-parametric Mann-Kendall rank statistic method and the Pettitt-Mann-Whitney change point statistics were used, respectively, for the change trend and change point analyses of daily temperature and precipitation at each station. The 5-year moving averages of 11 climate parameters showed a clear increase in the maximum and minimum annual average temperature in southwest China, however, no consistent increase for precipitation. In addition to temperature and precipitation, changes in the atmospheric pressure, wind speed, and cloud cover were also observed from this study. Changes in climate characteristics will or have altered the hydrologic cycle in the region, which would induce more frequent drought and flood, redistribution of water resources, rocky desertification, and carbon balance, and will ultimately have great impacts on the social, economic, and environmental life in the region.