Part 1 Climate Change and Corresponding Efforts in China
Many observations in recent 100 years show that the earth's climate is now experiencing significant change characterized by global warming. And the trend of climate change in China is generally consistent with that of global climate change. To address climate change and promote sustainable development, China has carried out various policies and measures, such as economic restructuring, energy efficiency improvement, development and utilization of hydropower and other renewable energy, ecological restoration and protection, as well as family planning, which has contributed significantly to the mitigation of climate change.
1.1 Observations and Trend of Climate Change in China
The Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) has clearly indicated that most of the global warming observed over the past 50 years was likely induced by the increase in concentrations of greenhouse gases (GHGs), such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), due to human activities. In the context of global warming, climate in China has experienced noticeable changes over the past 100 years as well. The major observed evidence of climate change in China includes the following:
- Temperature. Annual average air temperature in China has increased by 0.5-0.8ºC during the past 100 years, which was slightly larger than the average global temperature rise. Most of the temperature rise was observed over the last 50 years. The regional distribution of the temperature changes shows that the warming trend was more significant in western, eastern and northern China than in the south of the Yangtze River. The seasonal distribution of the temperature changes shows that the most significant temperature increase occurred in winter, and 20 consecutive warm winters were observed nationwide from 1986 to 2005;
- Precipitation. In the past 100 years, there was no obvious trend of change in annual precipitation in China, but there exists considerable variation among regions. The annual precipitation decreased gradually since the 1950s with an average rate of 2.9 mm/10a, although it increased slightly during the period of 1991-2000. The regional distribution of precipitation shows that the decrease in annual precipitation was significant in most of northern China, eastern part of the northwest, and northeastern China, averaging 20-40 mm/10a, with decrease in northern China being most severe; while precipitation significantly increased in southern China and southwestern China, averaging 20-60 mm/10a;
- Extreme climate/weather events. The frequency and intensity of extreme climate/weather events throughout China have experienced obvious changes during the last 50 years. Drought in northern and northeastern China, and flood in the middle and lower reaches of the Yangtze River and southeastern China have become more severe. The annual precipitation in most years since 1990 has been larger than normal, with the precipitation pattern being a dipole, corresponding to frequent disasters in the North and flood in the South;
- Sea level. The rate of sea level rise along China's coasts during the past 50 years was 2.5 mm/a, slightly higher than the global average;
- Glaciers. The mountain glaciers in China have retreated, and the trend is accelerating.
The trend of climate warming in China will further intensify in the future. The projections by Chinese scientists indicate that:
- The nationwide annual mean air temperature would increase by 1.3-2.1ºC in 2020 and 2.3-3.3ºC in 2050 as compared with that in 2000. The warming magnitude would increase from south to north in China, particularly in northwestern and northeastern China where significant temperature rise is projected. It is estimated that by 2030, the annual temperature would likely increase by 1.9-2.3ºC in northwestern China, 1.6-2.0ºC in southwestern China, and 2.2-2.6ºC in the Qinghai-Tibet Plateau;
- Precipitation in China would possibly increase during the next 50 years, with a projected nationwide increase of 2-3 percent by 2020 and 5-7 percent by 2050. The most significant increase might be experienced in southeastern coastal regions;
- The possibility of more frequent occurrence of extreme weather/climate events would increase in China, which will have immense impacts on the socio-economic development and people's living;
- The arid area in China would probably become larger and the risk of desertification might increase;
- The sea level along China's coasts would continue to rise;
- The glaciers in the Qinghai-Tibet Plateau and the Tianshan Mountains would retreat at an accelerated rate, and some smaller glaciers would disappear.