中国气候变化信息网 China Climate Change Info-Net

Submission on the IPCC TAR by the Chinese government

　The Third Assessment Report (TAR) of the IPCC reflects the major progress in current understanding of climate change during the last five years, while large uncertainties remain in many conclusions of the TAR.

The information contained in the TAR

　The TAR provides an assessment of new scientific information for policymakers. The following information would be useful for governments in making the response decisions:

　（1） Human activities have increased the atmospheric concentrations of greenhouse gases and aerosols since the pre-industrial era. Carbon dioxide concentrations, globally averaged surface temperature, and sea level are estimated to increase under all IPCC emissions scenarios during the 21st century;

　（2） Estimated climate change will have beneficial and adverse effects on both environmental and socio-economic systems;

　（3） Numerous possible adaptation options for responding to climate change have been identified that can reduce adverse and enhance beneficial impacts of climate change, but will incur costs;

　（4） The development and adoption of new technologies can be accelerated by technology transfer and supportive fiscal and research policies;

　（5） The impact of climate change is estimated to have different effects within and between countries. The challenge of addressing climate change raises an important issue of equity;

　（6） There are many opportunities including technological options to reduce near-term emissions, but barriers to their deployment exist. Development and transfer of environmentally sound technologies could play a critical role in reducing the cost of stabilizing greenhouse gas concentrations;

　（7） The costs of stabilizing CO2 concentrations in the atmosphere increase as the concentration stabilization level declines;

　（8） The climate change issue is part of the larger challenge of sustainable development. Local, regional, and global environmental issues are closely linked and affect sustainable development. Therefore, there are synergistic opportunities to develop more effective response options to these environmental issues that enhance benefits, reduce costs, and more sustainably meet human needs.

　The information contained in the TAR, however, should be thought as of being tentative due to the following uncertainties.

　(1) Observation and detection of climate change
　Caution should be paid to the uncertainties of the palaeo-records and palaeo-analyses. Due to the problems with tree ring indicator and other proxy data, the hemispheric or global temperature reconstructions in the last years could be only thought as preliminary ones. The range of natural variability in climate is known to be large over time scales of decadal to centuries. In addition, the ability of models to accurately simulate natural variability on long time scales and time histories of the various forcings in the last one or two centuries are also questionable. They obviously need to be improved before a robust conclusion about attribution of climate change could be obtained.

　(2) Estimation of future climate
　The following factors continue to hinder the progress in estimating the future climate change: (a) Knowledge gaps in understanding of processes and feedbacks in climate system. Improvements will surely be realized in addressing biogeochemical sequestration and cycling, in determining the spatial-temporal distribution of carbon dioxide sources and sinks, and in understanding and characterizing more completely dominant processes and feedbacks in the climate system; (b) Large uncertainty for forcings including aerosols. The present estimates of the uncertainty are partly subjective and the true forcing is likely to fall outside the estimated range of uncertainty in some cases; (c) Incomplete simulation skill of climate models due to the uncertainties in their formulation and the limited size of their calculations. Presently, the climate models cannot perfectly simulate the state of climate system. Works are needed to improve the global and regional climate models so that the regional details and extreme events could be well simulated.

　(3) Impacts and vulnerability assessment
　Climate change will excite both negative impact and positive impact. There may be many positive aspects of warming, such as the lengthened growing season in mid-to high latitude belts, the increased grain production in heat-restricted areas of higher latitude or altitude, the decreased energy consumption for heating in winter, and the improved water resource condition in some originally drier regions. In addition, little attention has been given to the uncertainties in assessing regional impacts of climate change and regional vulnerability to the change. Impact studies are based on regional projection or future regional scenarios of climate change, which is generally regarded as being premature.

　(4) Risks of climate change impacts
　The TAR tried to explain the risks induced by greenhouse gas concentration increase or temperature rise for human beings. However, this conclusion is largely dependent on expert judgments about climate effects at different temperature changes and their likelihood rather than quantitatively impact studies. In fact, it is extremely difficult at this stage to decide a specific level of greenhouse gas concentration critical or dangerous to ecosystems or human society due to the substantial uncertainty inherent in climate change impact studies. The basis for determining what constitutes "dangerous anthropogenic interference" varies among regions and depends upon the impacts of climate change and adaptive and mitigate capacity available to cope with climate change. Obviously more relevant research needs to be done.

　(5) Economic analyses of mitigation policies
　The TAR states that the amount of emissions reductions may be achieved with direct benefits exceeding direct costs. The finding remains a subject of active argument. Models for mitigation assessment need to be improved. The TAR also gives emphasis on market-based instruments for emission reduction and notes that the market based instruments are more efficient than administrative ones. However, Fairness and responsibility are important criteria, and the market instruments cannot solve the problems related to equity, which is a major issue in greenhouse gas emission reduction. Therefore, the cost-effective criterion could not be taken as the only factor for assessing the policies and measures. Moreover, the effectiveness of the market instrument depends on completely shared information. At present, serious dissymmetry in information sharing exists between developed and developing countries.

　(6) Equity and climate change mitigation
　In the TAR, attempts were made to address climate change mitigation in light of development, equity and sustainability (DES). However, the treatment of equity concerns over climate change mitigation is inadequate and biased towards economic implications of climate change mitigation actions. This observation may be drawn from the following points: (a) Mitigative capacity, as an important concept with equity implications, was not included in the SPM/WG3/TAR; (b) All the barriers, options, and potentials were assessed largely from a developed country perspective without paying attention to the specific situation of developing countries. For instance, market potentials and opportunities are meaningless to people in poverty; (c) The impacts on developing countries were given insufficient treatment. The models and assumptions were based on those in developed nations; Even there are some inclusions of such impacts, the understanding may be irrelevant if not wrong; (d) Development needs in developing countries should receive priority consideration in policy making. In the assessment exercise, however, climate change mitigation was by default number one objective. The emission in developed countries is different from that in developing countries in sense of their implications to human well-being. The former is the luxury emission, and the latter the survival emission.

　It is evident that a common but differentiated responsibility could not realized without properly resolving the difficulties mentioned above in mitigating climate change.

Possible activities by the IPCC

　The following questions should be further tackled in the future assessments:

　（1） The nature and causes of the natural variability of climate and its interactions with human-forced changes;

　（2） The detection and attribution of climate change;

　（3） The global carbon cycle;

　（4） The direct and indirect effects of changing distributions of aerosols;

　（5） The feedbacks in the climate system;

　（6） Details of regional and local climate change including climate extremes;

　（7） Socio-economic impacts of the past climate changes;

　（8） Equity issues for dealing with climate change and historical reponsibilities of the developed countries.

　The following activities are important in order to ensure the objectiveness and completeness of the IPCC assessments:

　（1） To help developing countries in diffusing the information contained in the IPCC reports to the publics and policy-makers;

　（2） To start the future assessment in a staggered manner to sufficiently guarantee the use of the relatively reliable scientific information contained in the Working Group One by the two other groups;

　（3） To raise special fund for training the young scientists of developing countries and for supporting the relevant workshops as a part of capacity building in developing countries;

　（4） To ensure more authors and reviewers from the developing countries to participate in the IPCC activities;

　（5） To initiate the technical papers or special reports, assessing the impact on developing countries of global climate change and the uncertainties in climate change science particularly in climate change detection and projection research.

Source: Ministry of Foreign Affairs of the People's Republic of China