This paper comprehensively analyzes major outcomes of the Copenhagen climate change conference 2009, looks forward key issues in the recent international negotiation on climate change, and also analyzes new international situation and challenges on addressing climate change faced by China. The paper also proposes systematic measures for China to enhance the capacity of addressing climate change, including taking the issue of addressing climate change into the legal system, expanding the social consciousness on addressing climate change, developing and popularizing climate-friendly technologies, enhancing the infrastructure of weak parts, raising the comprehensive capacity of China's adaptation to climate change, actively exploring the market system and mechanism for addressing climate change in accordance with China's national conditions, strengthening scientific research on climate change, and raising the scientific soft power on addressing climate change.

As expected from the focus of the climate change negotiation in the Copenhagen conference, what matters most to the follow-up international climate change negotiations will include the preparation of initial draft texts for negotiations, the further quantification of emission limitation or reduction commitments in the second commitment period of Kyoto Protocol by developed countries, the description of long-term goals and so on. The fifth assessment report (AR5) of IPCC will reinforce the scientific issues and fundamental conclusions elaborated and reached in previous reports with more convincing evidence and arguments, pay more attention to the regional aspect and give more words to the analysis of the economic costs of adaptation and mitigation, and of climate change and sustainable development. The conclusions drawn from the assessment of such issues as climate change detection and attribution, climate change impacts and key vulnerabilities, stabilization level of atmospheric greenhouse gas concentrations, adaptation options and their cost-effectiveness, mitigation options and socioeconomic costs, responsibility-sharing mechanism and equity will be a powerful driver to the negotiation progress.

Report of the Nongovernmental International Panel on Climate Change (NIPCC) is reviewed, which shows completely contradictory position to that of the Intergovernmental Panel on Climate Change (IPCC). It is indicated in the report of NIPCC that nature but not human activity caused global warming. Publication of present paper does not mean the support of the authors to the report of NIPCC. Listen to both sides and you will be enlightened, heed only one side and you will be henighted. Listening to the different voices would be much better than accepting the onesideness in promoting the science of climate change. Finally, comparing with the report of NIPCC, the view-point of "Copenhagen Diagnosis" is introduced, which represents the position of IPCC, and a critical review of the report of NIPCC is given.

Issures related to the pause of global warming in the last decade are reviewed. It is indicated that: 1) decade of 1999-2008 is still the warmest in the last 30 years, though temperature increment is near zero. 2) Natural factors such as volcanism, solar radiation, ENSO, and thermohaline circulation can impact the interannual and interdecadal variability of global mean temperature. However, it will not mask the global warming trend for a long time. (3) Temperatures of China continue to increase in 1999-2008, the increment is 0.4 to 0.5℃/10a.

Long-term trends of yearly and seasonal averages of tropospheric ozone over the whole country and some important regions of China during 1979-2005 were analyzed, based on the tropospheric ozone residue (TOR) data retrieved from satellite measurements. The relationship between TOR and the Southern Oscillation Index (SOI) was studied. The results show that, over the whole country, there was a slight increase of TOR in summer and a decrease in other seasons, while the overall trend for the whole period was insignificant. There were decreasing trends of TOR over the Pearl River Delta and the Sichuan Basin. Significant increasing trends of TOR were found over the North China Plain for all seasons except winter, with a maximum rate of 1.10 DU/10a for summer. There were significant correlations between TOR and SOI for some Chinese regions but not for the North China Plain, suggesting that the observed increasing trend of TOR over the North China Plain may not be linked with changes in atmospheric circulations.

A long lasting and extensive drought event over China was studied, that occurred in 1876-1878 under the background of the cold climate at the end of the Little Ice Age before the global warming. The dynamic process of the occurrence and development of the drought event was recovered from the historical literal records of China in the period by counting the yearly number of drought-hit counties and by plotting the distributions of yearly drought and its associated famine, locust plague and pestilence. This persistent drought disaster spread over 13 provinces with the center covering Shanxi, Henan and Shaanxi provinces, where the continuous non-soaking rain period exceeded 340 days, among which over 200 days was in 1877. The severity of the drought disaster even exceeds that of the drought during 1928-1930 which is considered as the most disastrous event in the 20th century. Besides, it is found that the drought event occurred in 1876-1878 when the sunspots were at the descent phase of the 11th activity period and at the minimum of the 12th activity period; and the El Nin～o was in its high frequency and extremely active period (level S++).

From the angle of manifold factors affecting natural dry-wet change, the research was performed in order to further understand and deal with climate change scientifically. Based on 1961-2007 observed data of nine climatic elements from 15 stations, the factor analysis was used to investigate the dry-wet climate change in the dry season in Yunnan. Three common factors were extracted from the nine climate variables to describe the dry-wet climate change for the dry season; and the features and causes of the change were clarified. The results show that the dry-wet climate has evidently changed since the early 1960s because of the influences of different factors in different decades. The general trends of dry-wet climate change were described as slow decrease in humidity and gradual enhancement in drought intensity. The climates were in a state of the drought of a weaker medium strength during the 1960s-1980s; but since the early 1990s, the markedly drier climate has continually occurred in the dry season owing to the misproportionally temporal distribution of rainfall and the climate warming. The variation tendency of the total precipitation for the dry season had uncertainty regardless of its obvious interdecadal changes of relatively small variance ratio; and its prominent interannual change led to the big interannual fluctuations for dry-wet climate.

The release of heat into the environment for human activities, such as energy consumption and human metabolism, is called anthropogenic heat release. During the process of anthropogenic heat release, the ground and troposphere will be heated, which have several impacts on urban climate change, and furthermore which may aggravate the global climate change. The statistical data of world energy consumption from British Petroleum and the demographic information from the United Nations Population Division are used to explore the impacts of anthropogenic heat on the global climate change. The results indicate that the current global annual climatic forcing of anthropogenic heat release is not yet large, about 0.031W/m²; but with the population and the total energy consumption increasing, the future global annual climatic forcing of anthropogenic heat release may reach 0.30 W/m².

The water and heat conditions change resulted from climate change has strongly affected agricultural production, and famers take various kinds of measures to adapt to impacts of climate change. To further understand the effects of climate change on main grain crops and the adaptive measures taken by farmers, we analyzed changes in the planting structure of main grain crops based on the daily average temperature and the data from "China Agricultural Yearbook" published from 1980 to 2007 by National Bureau of Statistics as well as research results from literature. The results indicate that planting proportion changes of main grain crops were obvious on the nationwide scale from 1980 to 2007 as the result of the climate warming, the wheat planting proportion was more sensitive to climate change, and it fluctuated largely; the paddy rice planting proportion changed in opposite trends in northern and southern China, and its change has become slower; the corn planting proportion continued to increase, its change was enlarging; the planting structure of the three main grain crops (paddy rice, wheat and corn) all changed in 2000 with different increasing/declining trends. Furthermore, the crops ripe system and the multiple cropping index also changed obviously; the north boundary of crops planting has continuously moved northward. The winter wheat planting area in northern China in 2007 moved northward by nearly 100 km compared with the 1960s. The paddy rice planting area has greatly expanded in Heilongjiang Province, where the paddy rice has dominated in the original corn planting areas.

The macroeconomic cost of CO₂ emission abatement may be greatly different for countries in different development phases. Estimating this cost scientifically is of important scientific and practical significance. This paper estimates the macroeconomic cost of carbon dioxide (CO₂) emission abatement in China, employing the input-output analysis with the multi-objective programming approach. The results show that the effect of abating CO₂ emission on China's economy is significant. Under the present conditions, the estimated macroeconomic cost of CO₂ emission abatement for China in 2010 is approximately between 3100 RMB/t and 4024 RMB/t. The stronger the abatement actions are, the higher the macroeconomic cost of per unit emission reduction would be. Mining, oil industry, chemical industry, and metal smelting industry are high CO₂-emission industries, but meanwhile they have more potential to abate their CO₂ emissions.

Three types of low-carbon vehicle technologies in China are reviewed. Potential energy-saving effects are listed for those integrated energy-saving technologies for conventional vehicles. Low-carbon transitions, including alternative vehicle powertrain systems and fuels, are discussed on their development status and trends, including the life-cycle primary fossil energy use and greenhouse gas emissions of each pathway. To further support the low-carbon vehicle technologies development, integrated policies should seek to 1) employ those integrated energy-saving technologies; 2) apply hybrid electric technology; 3) commercialize electric vehicles through battery technology innovation; 4) support fuel cell buses and hydrogen technology R&D for future potential applications; 5) boost the R&D of second generation biofuel technology; and 6) conduct further research on applying low-carbon technologies including CO₂ capture and storage technology to coal-based transportation solutions.

Solving the problem of climate change must depend on technology innovation. Technology innovation is seen not only as a technological problem, but also as an interaction course among science, engineering, economic factors and institutions. According to the framework of "technological regime" we can identify three types of innovations: incremental innovation, disruptive innovation and radical innovation. Radical innovation and part of disruptive innovation are locked-in to the hydrocarbon energy system, so adjustment of current policies is necessary. Obviously, governments including China's have begun to adopt new policy instruments due to the complexity of technology innovation.

On the eve of the COP15, the German Advisory Council on Global Change (WBGU) proposed a budget approach for solving the climate dilemma of existing international climate change regime, this proposal aimed to realize the long-term emission reduction target and build global low-carbon economy by managing the future greenhouse gases emission space. German carbon budget proposal is similar to China's carbon budget proposal published in the COP14, but the both still differ in some parameters, path of emission reduction, historical emission responsibility, etc. German proposal might try to meet the demand of both the north and south countries, but the unfair design makes it unfeasible.