Based on the winter half year (from November to the April of next year) minimum temperature data at 160 stations in China during 1955-2005, the abrupt changes in minimum temperature were analyzed by using the Mann-Kendall statistic test. The probability distributions of minimum temperature series for the colder period (1955/1956-1988/1989) and the warmer period (1989/1990-2004/2005) were given, and the spatial differences of minimum temperature between the two climatic periods were also compared. The results show that: 1) the significant rising of minimum temperature occurred in the end of the 1980s, with a rising amplitude larger than that of mean temperature; 2) after the warming the probability of lower minimum temperature has apparently reduced and that of higher minimum temperature increased; 3) statistically, the rising trends of minimum temperature were all significant over most regions in China except those in Southwest China.

Historic and recent observational data of SO2 and NOx from Lin’an and Longfengshan background stations, located in the Yangtze Delta and the Northeast Plain region, respectively, are analyzed in order to study the differences in concentrations of these climate relevant acidic gases between the two regions and impacts of anthropogenic emissions on the gases since about one decade ago. The past and more recent levels of the gases are compared between the two sites, long-term trends of the gases at both sites are estimated, and the NOx/SO2 ratios for the two stations are obtained using the correlation method. The results show that in the middle 1990s the levels of SO2 and NOx were already considerably high at the background site of the Yangtze Delta region and since that time the anthropogenic emissions have only caused a significant increase in NOx concentration, making NOx another major pollutant in addition to SO2. Data from Longfengshan station suggest that the levels of acidic gases in the Northeast Plain region were very low in the past, and are still not high at present. However, the levels of these acidic gases in this less polluted region have been increasing at very high rates, therefore, the future levels of these gases in the region are not optimistic.

This paper synthesizes the studies on China’s soil organic carbon (SOC) stock and the dynamics, especially of croplands and discusses the significance in climate change mitigation of the state. The status of SOC stock and its role in climate mitigation of China are overviewed as: a relatively lower SOC storage with greater regional variability; an existing SOC stock increase trend with significant SOC sequestration capacity; technology and climate policy required for enhancing SOC stock and the climate change mitigation capacity building for China. It is proposed that investments in research and development for enhancing SOC stock, development of climate policy and incentives should be pursued in the near future to develop climate friendly agriculture favoring SOC sequestration and ensuring double win effects with food production and climate change mitigation in agriculture of China.

By comparing the global carbon cycle of the IPCC assessment reports in 1990, 1996, 2001 and 2007, it was found that despite the estimated sizes of the main carbon reservoirs and the fluxes between them in the four reports were similar, the estimated carbon fluxes between surface and intermediate-deep sea waters were quite different. The δ¹³C budget was used to test the reasonable range of these fluxes. The results show that the IPCC assessment reports in 1996 and 2007 have overestimated, whereas those in 1990 and 2001 underestimated the fluxes between surface and intermediate-deep sea waters.

Using the paleo-vegetation maps previously reconstructed with pollen data and the modern carbon density data, the changes in terrestrial carbon storage in the Holocene in mainland China were analyzed. Our analysis shows that the terrestrial carbon storage of the country generally increased from 10 kaBP to 6 kaBP, and reached the maximum value at 6 kaBP; since then, it continuously decreased, with the most rapid drop occurring during the last 2 ka. The decrease in terrestrial carbon storage after 6 kaBP might be attributed to the human activities since the Neolithic Age.

The Brazilian proposal for differentiated greenhouse gas emissions reduction targets for Annex I parties of the UNFCCC should be based on attribution of contribution to global climate change due to historical emissions of greenhouse gases. Numerical models are used to calculate the climate change due to past emissions of greenhouse gases, and to partition the climate change among nations or regions. We use historical emissions and population databases, and a simple climate model (SCM) to calculate national and their per capita historical contributions to climate change. There is great difference between the results using national accumulative emissions and accumulative per capita emissions data, respectively. The developing countries are in lower accumulative per capita emission than the developed countries. Our calculations give the per capita contributions to climate change in the evaluation year over the period between the choosing start and end years. Comparing the contribution of per capita historical emissions calculated by SCM with the accumulative per capita emissions, we find that the results are similar. For equity between humans, there is a need to define new indicators to consider the differentiation of per capita historical emission responsibilities such as contributions of per capita historical emissions to global warming (sea level rise, etc.).

Global warming has become an important environmental issue, and water is the resource most directly affected by climate change. Global warming will alter the amount and spatial distribution of available water resources by accelerating the atmospheric circulation and the hydrological cycle. Moreover, global warming would likely lead to more severe water shortages, deterioration of aquatic systems and more floods disasters. In this paper, the possible impacts of global warming on water security with respect to flood control, water supply, aquatic environment, and water conservancy engineering, are discussed.

The issue on screening for climate change adaptation is addressed. A screening approach is developed for assessing climate change impacts on water sector and integrating adaptation for water resource projects, and three phases for screening climate change adaptation are introduced that include the semi-quantitative & quantitative analysis, and the evaluation of different adaptation options on the water resources affected by climate change in China. According to different climatic regions facing different problems on water resource, four representative regions in China are chosen in the project; after setting up different objectives, this paper demonstrates the comprehensive research on climate change adaptation, and proposes new ideas, framework and methodologies on screening for climate change impacts and adaptation. This research provides the effective framework and methodology for the planning and risk management of the impacts of future climate change on water resource.

Based on the review of the successive four assessment reports of the IPCC WGII on climate change impacts on streamflow from 1990 to 2007, it is summarized that the first (FAR) and second (SAR) assessment reports were regarded as the first generation studies, featuring the impacts of mean climate change on streamflow and the adaptation, while the third (TAR) and forth (AR4) assessment reports as the second generation studies, emphasizing the impacts of anthropogenically and naturally forced climate changes on streamflow and the adaptation. The development process and existed problems of traditional assessing methodologies of the impacts of climate change on hydrology and water resources are analyzed. It is pointed out that the impacts of decadal and multi-decadal variabilities of climatic variables on streamflow can be identified in the traditional methodology of hydrological impact studies, but without consideration of daily, seasonal and interannual variabilities, which are related with changes in the frequency and intensity of extreme events. As the results, the negative impacts of climate warming on droughts, floods and water demand of irrigation might be underestimated. As for further studies, the paper comes to a conclusion suggesting the enhancement of the interdisciplinary study of hydrology and climatology in the next IPCC assessment report.

Based on the projected runoff depth by ECHAM5/MPI-OM climate model for the Yangtze River basin under SRES A2, A1B, B1 greenhouse gas emission scenarios in 2001-2050, the spatial and temporal patterns of future surface water resource in the Yangtze River basin were analyzed. The results show that the long-term average annual surface water resource volumes of the Yangtze River under the three scenarios are similar, while interannual fluctuations are complicated with different trends. The surface water resource declines gradually in fluctuations under the A2 scenario, shows no obvious trends under the A1B scenario, and displays a relatively significant increasing trend under the B1 scenario. Decadal variations of surface water resource are notable, showing an overall decline trend under all the three scenarios in 2001-2030, while an increasing trend to varying extent after the 2030s, especially in summer and winter. The projected future water resource volume in the Yangtze River basin overally remains at the current level, showing an evident spatial uneven feature.

Outputs of control experiment and CO₂-doubling experiment with GFDL-CM2.1 coupled model were used to evaluate the effect of CO₂-doubling on changes in extreme precipitation in China. The result shows that CO₂-doubling would cause a prominent increase in annual extreme precipitation amount and precipitation intensity in eastern China, and a prominent increase in annual extreme precipitation frequency in eastern China except the south part of North China. Furthermore, CO₂-doubling would influence the distribution of extreme precipitation in spring and summer, leading to increases in the frequency, intensity and amount of extreme precipitation in most of eastern China. However, the annual precipitation in both the south part of North China and the mid-lower reaches of the Yangtze River would decrease, due to the reduction of the wet days in spring and summer as well as in light rain and moderate rain.

China’s CO₂ emissions change during 1971-2005 was analyzed by using Kaya Identity in combination with macroeconomic background evolution. The study indicates that the increase of CO₂ emission is mainly due to rapid economic development and population growth. And that to a large extent, the decrease in energy intensity and the decarburization of energy structure in China jointly limit the augmentation of overall CO₂ emission at a higher rate. So the improvement in energy efficiency and the diversification of energy structure by using more renewable energy are considered to play an important role in realizing the binding target of 20% reduction in GDP energy consumption during the 11th Five-Year Plan.

Temperatures from early March to early July during 1961-2004, at 10 stations in the Yellow River irrigation region of Ningxia were analyzed. The results show that the temperature during the growing season of spring wheat increased obviously. The t-test indicates that a temperature abrupt change occurred in 1989 with an average rise of 0.7℃. Over various growth stages of spring wheat, the temperature increased, but it didn’t exceed the suitable range. The temperature-sensitive index of spring wheat was positive from middle March to early April and from May to early June, therefore the climate warming over the two periods was favorable to wheat growth; however it was negative from middle June to early July and from middle to late April, thus the climate warming over the two periods was unfavourable to wheat growth. Overally, the contribution of climate warming to spring wheat yield was -2.6%.

Long-term climate change mitigation target would highly constrain global carbon emissions in the future. Carbon permit allocation under the long-term mitigation target would impact development space for all countries, involving the fundamental interests. Some developed countries advocate the principle of per capita emission convergence while China and other developing countries propose the principle of convergence of cumulative emission per capita to consider historical responsibility. If the latter is used for carbon permit allocation, CO2 emissions of developed countries since the industrial revolution have far exceeded their allocated permits. Developed countries’ high per capita emissions at present and for quite a long period in the future would continue to occupy emission spaces for developing countries. Therefore, developed countries must commit to deeper emission reduction for the next commitment period at the Copenhagen conference, in order to achieve the emission pathway under the long-term emission reduction target, and to save necessary development space for developing countries. At the same time, developing countries must be enabled with adequate financial and technical support by developed countries as compensation for their excessive occupation of the development space for developing countries, to improve developing countries’ capacity to cope with climate change under the framework of sustainable development. On the one hand, we should uphold on the principle of equity to ensure reasonable emission space for our country (China) in the international climate change negotiation; while on the other hand, we should enhance development toward low-carbon economy to protect global environment and to achieve sustainable development.