Public perceptions of global warming

In this paper, we examine the way public opinion responds to the prospect of global warming. In particular, we focus on the public's willingness to pay in order to prevent various hypothetical climate scenarios from transpiring. To this end, fractional factorial survey methods are employed with a sample of over 600 residents of Southern California. By and large, the public is able to understand and evaluate rather complicated hypothetical climate scenarios, but the public appreciates some features of climate far better than others. In this context, the contingent valuation estimates we provide, while promising, are clearly not ready of consideration by policy makers.     

基于中国全球海洋预报系统(CGOFS)的全球高分辨率再分析产品评估

通过同化系统将观测资料与海洋数值模式融合得到的海洋再分析产品为海洋科学研究提供了重要的资料基础.本文采用WOA,SODA,AVISO和GLORS四种数据资料与我国自主研发的中国全球海洋预报系统(CGOFS)的气候态结果进行了对比,结果表明:CGOFS和SODA的全球海表面温度与WOA的均方根误差分别为0.51和0.43℃.CGOFS和SODA的海表面盐度与WOA的均方根误差分别为0.48和0.40 PSU;海流方面,CGOFS能较好的刻画主要大洋环流分布及赤道潜流的垂向结构;CGOFS的全球海表面高度异常与AVISO的均方根误差为0.018m;多年月平均海冰外缘线覆盖面积介于SODA和GLORS之间,海冰体积的生消规律与SODA和GLORS一致.总体来看,CGOFS全球高分辨率海洋再分析产品的气候态结果与国际同类产品基本一致,可为提升我国海洋综合科技实力提供可靠的资料保障.     

An Impact of Hydrostatic Extraction Scheme on BMRC’s Global Spectral Model

There are two important features in geophysical fluid dynamics. One is that the atmospheric and oceanic equa-tions of motion include the Coriolis force; another is that they describe a stratified fluid. The hydrostatic extraction scheme, or standard stratification approximation, posed by Zeng (1979), reflects the second aspect of geophysical flu-id dynamics. There exist two major advantages in this scheme; accurate computation of the pressure gradient force can be obtained over steep mountain slopes, and the accumulation error in vertical finite differencing can be reduced, especially near the tropopause.Chen et al (1987) introduced the hydrostatic extraction scheme into a global spectral model, which attained pre-liminary success at low resolution. Zhang and Sheng et al (1990) developed and improved the hydrostatic extraction scheme in a global spectral model, in which C0, the parameter that represents the stratification of the reference at-mosphere, changes not only with height, but also with latitude. The scheme has been incorporated BMRC’s global spectral model (IAPB). Four 5-day forecasts have been performed to test the IAPB with the hydrostatic extraction scheme. Objective verifications demonstrate a positive effect of the hydrostatic extration scheme on BMRC’s model, particularly at upper levels, over the tropics and the Antartic region.     

Trends in global temperature

Statistical models consisting of a trend plus serially correlated noise may be fitted to observed climate data such as global surface temperature, the trend and noise representing systematic change and other variations, respectively. When such a model is fitted, the estimated character of the noise determines the precision of the estimated trend, and hence the precision of the estimate of the magnitude of the systematic change in the variable considered. The results of fitting such models to global temperature imply that there is uncertainty in the amount of temperature change over the past century of up to ± 0.2 °C, but that the change of around one half of a degree Celsius is significantly different from zero.The statistical models for climate variability also imply that the observed temperature data provide only imprecise information about the climate sensitivity. This is defined here as the equilibrium response of global temperature to a doubling of the atmospheric concentration of carbon dioxide. The temperature changes observed to date are compatible with a wide range of climate sensitivities, from 0.7 °C to 2.2 °C. When data uncertainties are taken into account, the interval widens even further.     

Estimating global solar radiation

A model is presented to calculate daily totals of global solar radiation. First, cloudless sky radiation is evaluated from transmission due to absorption and scattering. Cloud effects are added using cloud layer transmission. A simple expression to account for additional radiation due to reflection between the ground surface and cloud bases is also included. Atmospheric transmissions are obtained from previous studies. Precipitable water and observations of cloud type and amount for different layers in the atmosphere are the only meteorological variables required. The model is evaluated and tested with data collected at stations in and around Lake Ontario: a lake station near Grimsby in 1969 and land stations at Burlington, Scarborough, Peterborough, Trenton and Kingston, Ontario in 1972 and 1973 during the International Field Year for the Great Lakes. Good agreement between calculated and measured radiation was obtained at all stations, particularly for 5- and 10-day means. Model performance was largely independent of both cloud amount and season.     

Antarctica and global change

The Antarctic region of the globe is of special importance for a wide range of studies of global change. The IGBP research activities needing special focus for global change should be multidisciplinary, should involve both the geosphere and the biosphere, and should be of global as well as local interest. There are a number of important Antarctic research topics which fit these criteria.A decrease of Antarctic sea ice has a positive feedback on global warming. Reduction in the sea ice also impacts on deep ocean circulation and can give a positive feedback to the increase of atmospheric carbon dioxide by the reduction of a deep ocean sink. Changes in the mass balance of the Antarctic ice sheet impact on global sea level. A unique historic record of past climate and global environmental changes is being obtained from deep core drilling in the Antarctic ice sheet. Decreases of stratospheric ozone are most pronounced over the Antarctic in spring. The impact of increases in ultraviolet radiation on the biosphere can be studied in the Antarctic as a precurser to possible changes developing elsewhere around the globe. Changes in the atmosphere and ocean circulations resulting from the decrease in Antarctic sea ice cover can have important effects on ocean surface temperatures which impact on the climates of the continents.These topics are discussed briefly and a number of Antarctic research areas are highlighted which build on existing or planned international programmes and which can make critical contributions to multidisciplinary studies of global change.     

On the tropical origin of uncertainties in the global land precipitation response to global warming

Understanding the response of the global hydrological cycle to recent and future anthropogenic emissions of greenhouse gases and aerosols is a major challenge for the climate modelling community. Recent climate scenarios produced for the fourth assessment report of the Intergovernmental Panel on Climate Change are analysed here to explore the geographical origin of, and the possible reasons for, uncertainties in the hydrological model response to global warming. Using the twentieth century simulations and the SRES-A2 scenarios from eight different coupled ocean–atmosphere models, it is shown that the main uncertainties originate from the tropics, where even the sign of the zonal mean precipitation change remains uncertain over land. Given the large interannual fluctuations of tropical precipitation, it is then suggested that the El Niño Southern Ocillation (ENSO) variability can be used as a surrogate of climate change to better constrain the model reponse. While the simulated sensitivity of global land precipitation to global mean surface temperature indeed shows a remarkable similarity between the interannual and climate change timescales respectively, the model ability to capture the ENSO-precipitation relationship is not a major constraint on the global hydrological projections. Only the model that exhibits the highest precipitation sensitivity clearly appears as an outlier. Besides deficiencies in the simulation of the ENSO-tropical rainfall teleconnections, the study indicates that uncertainties in the twenty-first century evolution of these teleconnections represent an important contribution to the model spread, thus emphasizing the need for improving the simulation of the tropical Pacific variability to provide more reliable scenarios of the global hydrological cycle. It also suggests that validating the mean present-day climate is not sufficient to assess the reliability of climate projections, and that interannual variability is another suitable and possibly more useful candidate for constraining the model response. Finally, it is shown that uncertainties in precipitation change are, like precipitation itself, very unevenly distributed over the globe, the most vulnerable countries sometimes being those where the anticipated precipitation changes are the most uncertain.     

Scenarios with MIT integrated global systems model: significant global warming regardless of different approaches

A wide variety of scenarios for future development have played significant roles in climate policy discussions. This paper presents projections of greenhouse gas (GHG) concentrations, sea level rise due to thermal expansion and glacial melt, oceanic acidity, and global mean temperature increases computed with the MIT Integrated Global Systems Model (IGSM) using scenarios for twenty-first century emissions developed by three different groups: intergovernmental (represented by the Intergovernmental Panel on Climate Change), government (represented by the U.S. government Climate Change Science Program) and industry (represented by Royal Dutch Shell plc). In all these scenarios the climate system undergoes substantial changes. By 2100, the CO₂ concentration ranges from 470 to 1020 ppm compared to a 2000 level of 365 ppm, the CO₂-equivalent concentration of all greenhouse gases ranges from 550 to 1780 ppm in comparison to a 2000 level of 415 ppm, oceanic acidity changes from a current pH of around 8 to a range from 7.63 to 7.91, in comparison to a pH change from a preindustrial level by 0.1 unit. The global mean temperature increases by 1.8 to 7.0°C relative to 2000. Such increases will require considerable adaptation of many human systems and will leave some aspects of the earth??s environment irreversibly changed. Thus, the remarkable aspect of these different approaches to scenario development is not the differences in detail and philosophy but rather the similar picture they paint of a world at risk from climate change even if there is substantial effort to reduce emissions.     

全球增暖和极端事件对全球温度场关联性的影响

用中国国家气象信息中心整编的1971—2006年中国693个地面基准站日降水资料、同期美国JTWC最佳路径资料和NCEP/NCAR再分析资料,对热带气旋(TC)远距离暴雨进行统计分析和诊断研究。结果表明:36a中有14.7%的TC产生远距离暴雨。TC远距离暴雨事件遍及中国大陆27个省(市、自治区),其中,环渤海地区和川陕交界处为中国TC远距离暴雨高发区。远距离暴雨集中发生在6—9月。34.6%的TC远距离暴雨具有影响范围广、降水强度大的特点。诊断分析表明,TC远距离暴雨能否产生的关键在于热带气旋东侧环流能否将水汽输送到中纬度槽前,如果有高气压或偏北气流对水汽输送的阻断,就不会形成远距离暴雨。     

Effect test of predicting global warming北大核心CSCD

[No abstract available]     

Baseline scenarios of global environmental change

This paper presents three baseline scenarios of no policy action computed by the IMAGE 2 model. These scenarios cover a wide range of coupled global change Indicators, including: energy demand and consumption; food demand, consumption, and production; changes in land cover including changes in extent of agricultural land and forest; emissions of greenhouse gases and ozone precursors; and climate change and its impacts on sea level rise, crop productivity and natural vegetation. Scenario information is available for the entire world with regional and grid scale detail, and covers from 1970 to 2100. The scenarios indicate that the coming decades could be a period of relatively rapid global environmental change as compared to the period before and after. The natural vegetation in industrialized regions could be threatened by climate change, but abandonment of agricultural lands could also make new lands available for reforestation and revegetation. The opposite is true for most of Asia and Africa. Here the impacts of climate change on vegetation may not be as significant as in temperate climates, but the demand for food will lead to a significant expansion of agricultural lands at the expense of remaining forests and other natural areas.     

Air conditioning and global inequality

As global temperatures go up and incomes rise, air conditioner sales are poised to increase dramatically. Recent studies explore the potential economic and environmental impacts of this growth, but relatively little attention has been paid to the implications for inequality. In this paper we use household-level microdata from 16 countries to characterize empirically the relationship between climate, income, and residential air conditioning. We show that both current and future air conditioner usage is concentrated among high-income households. Not only do richer countries have much more air conditioning than poorer countries, but within countries adoption is highly concentrated among high-income households. The pattern of adoption is particularly stark in relatively low-income countries such as Pakistan, where we show that the vast majority of adoption between now and 2050 will be concentrated among the upper income tercile. We use our model to forecast future adoption, show how patterns vary across countries and income levels, and discuss what these patterns mean for health, productivity, and educational inequality.