Upscaling Tropical Deforestation: Implications for Climate Change

This article examines the implications of upscaling tropical deforestation for climate change. In this case, upscaling refers to the extrapolation and aggregation of deforestation to the grid scale that is used in global climate models (GCMs). The upscaling of deforestation emphasizes the extent of forest loss, and assumes that deforestation is a homogeneous and instantaneous process. The structure of deforested landscapes is usually disregarded in "upscaled" experiments, and the intensity of deforestation is seldom considered. Consequently, the atmospheric response to a heterogeneous surface is not addressed. Furthermore, climatically significant soil and vegetation parameters associated with complex and dynamic deforested landscapes are ignored. These factors underscore the need for more realistic representation of tropical deforestation in modeling studies. Several recent attempts to address the issue of scale in deforestation studies are described in the article.     

Tropical Deforestation and the Kyoto Protocol

The current annual rates of tropical deforestation from Brazil and Indonesia alone would equal four-fifths of the emissions reductions gained by implementing the Kyoto Protocol in its first commitment period, jeopardizing the goal of Protocol to avoid “dangerous anthropogenic interference” with the climate system. We propose the novel concept of “compensated reduction”, whereby countries that elect to reduce national level deforestation to below a previously determined historical level would receive post facto compensation, and commit to stabilize or further reduce deforestation in the future. Such a program could create large-scale incentives to reduce tropical deforestation, as well as for broader developing country participation in the Kyoto Protocol, and leverage support for the continuity of the Protocol beyond the 2008–2012 first commitment period.     

气候增暖对广东省植物物候变化的影响

根据广东省气象观测资料和10个农业气象观测站的物候观测资料,分析了1982~2004年温度变化对广东省木本植物物候变化的影响,并建立了物候期差异与温度之间的关系模式,分析了当前气候增暖背景下物候期对温度变化的响应关系。结果表明:平均温度上升,木本植物春季物候期提前;平均温度下降,木本植物春季物候期推迟。物候期的提前与推迟对温度的上升与下降的响应是非线性的。在同等升降温幅度情况下,降温导致的物候期推迟幅度较升温导致的物候期提前幅度大。     

Alternatives to the Global Warming Potential for Comparing Climate Impacts of Emissions of Greenhouse Gases

The Global Warming Potential (GWP) is used within the Kyoto Protocol to the United Nations Framework Convention on Climate Change as a metric for weighting the climatic impact of emissions of different greenhouse gases. The GWP has been subjected to many criticisms because of its formulation, but nevertheless it has retained some favour because of the simplicity of its design and application, and its transparency compared to proposed alternatives. Here, two new metrics are proposed, which are based on a simple analytical climate model. The first metric is called the Global Temperature Change Potential and represents the temperature change at a given time due to a pulse emission of a gas (GTP_P); the second is similar but represents the effect of a sustainedemission change (hence GTP_S). Both GTP_P and GTP_S are presented as relative to the temperature change due to a similar emission change of a reference gas, here taken to be carbon dioxide. Both metrics are compared against an upwelling-diffusion energy balance model that resolves land and ocean and the hemispheres. The GTP_P does not perform well, compared to the energy balance model, except for long-lived gases. By contrast, the GTP_S is shown to perform well relative to the energy balance model, for gases with a wide variety of lifetimes. It is also shown that for time horizons in excess of about 100 years, the GTP_S and GWP produce very similar results, indicating an alternative interpretation for the GWP. The GTP_S retains the advantage of the GWP in terms of transparency, and the relatively small number of input parameters required for calculation. However, it has an enhanced relevance, as it is further down the cause–effect chain of the impacts of greenhouse gases emissions and has an unambiguous interpretation. It appears to be robust to key uncertainties and simplifications in its derivation and may be an attractive alternative to the GWP.     

全球气候变暖的检测及成因分析

文章对近年来有关全球气候变暖中一些问题的研究进展作了总结,主要结论如下：全球平均地面气温在过去一百年来上升0.5℃。80年代是近百年来最暖的10年。90年代初继续变暖。1990年是近百年来最暖的一年。1991年仅次於1990年。但是近百年气候变暖的幅度仍未超过自然变率。近千年中,中世纪暖期（900—1300年）的温暖程度就可能与20世纪相当,而小冰期（1550—1850年）气温则可能比20世纪低1.0—1.5℃。已经证实,对几十年到几百年尺度,太阳活动强时太阳总辐射也强,但变化幅度尚待进一步确定。强火山爆     

气候变暖对人类健康的影响

气候变暖是人类面临的严重环境问题,不仅危及人类健康,而且影响当今人类的生存条件及未来人类的可持续发展,引起国际社会和各国政府的普遍关注。根据近10年国内外最新的相关科研成果,分析研究了气候变暖对非病原性疾病的影响。分析表明,气候变暖助长病原性媒介疾病的传播,可能激活某些新病毒,增加疟疾等疾病,助长SARS、禽流感等对人类健康的危害,并结合我国的国情提出对策建议。     

Effects of Climate Change on Rice Production in the Tropical Humid Climate of Kerala, India

The CERES-Rice v3. crop simulation model, calibrated and validated for its suitability to simulate rice production in the tropical humid climate Kerala State of India, is used for analysing the effect of climate change on rice productivity in the state. The plausible climate change scenario for the Indian subcontinent as expected by the middle of the next century, taking into account the projected emissions of greenhouse gases and sulphate aerosols, in a coupled atmosphere-ocean model experiment performed at Deutsches Klimarechenzentrum, Germany, is adopted for the study. The adopted scenario represented an increase in monsoon seasonal mean surface temperature of the order of about 1.5°C, and an increase in rainfall of the order of 2 mm per day, over the state of Kerala in the decade 2040–2049 with respect to the 1980s. The IPCC Business-as-usual scenario projection of plant usable concentration of CO₂ about 460 PPM by the middle of the next century are also used in the crop model simulation. On an average over the state with the climate change scenario studied, the rice maturity period is projected to shorten by 8% and yield increase by 12%. When temperature elevations only are taken into consideration, the crop simulations show a decrease of 8% in crop maturity period and 6% in yield. This shows that the increase in yield due to fertilisation effect of elevated CO₂ and increased rainfall over the state as projected in the climate change scenario nearly makes up for the negative impact on rice yield due to temperature rise. The sensitivity experiments of the rice model to CO₂ concentration changes indicated that over the state, an increase in CO₂ concentration leads to yield increase due to its fertilisation effect and also enhance the water use efficiency of the paddy. The temperature sensitivity experiments have shown that for a positive change in temperature up to 5°C, there is a continuous decline in the yield. For every one degree increment the decline in yield is about 6%. Also, in another experiment it is observed that the physiological effect of ambient CO₂ at 425 ppm concentration compensated for the yield losses due to increase in temperature up to 2°C. Rainfall sensitivity experiments have shown that increase in rice yield due to increase in rainfall above the observed values is near exponential. But decrease in rainfall results in yield loss at a constant rate of about 8% per 2 mm/day, up to about 16 mm/day.     

The Potential Effects of Elevated Co2 and Climate Change on Tropical Forest Soils and Biogeochemical Cycling

Tropical forests are responsible for a large proportion of the global terrestrial C flux annually for natural ecosystems. Increased atmospheric CO₂ and changes in climate are likely to affect the distribution of C pools in the tropics and the rate of cycling through vegetation and soils. In this paper, I review the literature on the pools and fluxes of carbon in tropical forests, and the relationship of these to nutrient cycling and climate. Tropical moist and humid forests have the highest rates of annual net primary productivity and the greatest carbon flux from soil respiration globally. Tropical dry forests have lower rates of carbon circulation, but may have greater soil organic carbon storage, especially at depths below 1 meter. Data from tropical elevation gradients were used to examine the sensitivity of biogeochemical cycling to incremental changes in temperature and rainfall. These data show significant positive correlations of litterfall N concentrations with temperature and decomposition rates. Increased atmospheric CO₂ and changes in climate are expected to alter carbon and nutrient allocation patterns and storage in tropical forest. Modeling and experimental studies suggest that even a small increase in temperature and CO₂ concentrations results in more rapid decomposition rates, and a large initial CO₂ efflux from moist tropical soils. Soil P limitation or reductions in C:N and C:P ratios of litterfall could eventually limit the size of this flux. Increased frequency of fires in dry forest and hurricanes in moist and humid forests are expected to reduce the ecosystem carbon storage capacity over longer time periods.     

Potential Effects of Differential Day-Night Warming in Global Climate Change on Crop Production

Recent studies on the nature of global warming indicate the likelihood of an asymmetric change in temperature, where night-time minimum temperature increases more rapidly than the day-time maximum temperature. We used a physically based scenario of asymmetric warming combined with climate change scenarios from General Circulation Models (GCMs) outputs and the EPIC (Erosion Productivity Impact Calculator) plant process model to examine the effects of asymmetric temperature change on crop productivity. Our results indicated that the potential effects of global change on crop productivity may be less severe with asymmetric day-night warming than with equal day-night warming.     

气候变暖对黑龙江省气候和极端天气事件的影响及防御对策

黑龙江省1980年以来气候变暖已成为事实，气候变暖导致天气气候极端事件的发生，依此提出防御时策。     

气候变暖对呼和浩特地区自然物候的影响

分析了1982—2007年气候变暖对内蒙古呼和浩特、武川自然物候的影响,结果表明:①春季,土壤表层解冻呼和浩特晚于武川,其余物候呼和浩特早于武川;秋季物候均为武川早于呼和浩特。且两地物候间距均为"豆雁始(绝)见>气象水文物候期>植物始花(落叶)";两地植物物候间呈显著的正相关,豆雁始(绝)见呈显著负相关,气象水文物候期间相关不显著;②两地年、春、秋季平均气温呈增加趋势,植物物候春季提前,秋季延迟趋势显著,与气温有很强的响应关系;豆雁在呼和浩特始见提前,绝见延迟,武川与此相反,豆雁与气温有一定的响应关系;气象水文物候期也具有春季提前,秋季延迟的趋势,与气温相关不显著。     

地球失控增暖可能性的数值模拟

通过改变太阳常数引进强外辐射强迫的变化,利用NCAR气候系统模式CSM1.4,就气候系统对强外辐射强迫下的失控增暖效应进行了初步研究。结果表明:气候对于太阳常数分别增加2.5%、10%与增加25%的响应有所不同,即对于较小的强迫,气候系统的响应是线性的;而对于较大的强迫,响应很可能是非线性的。对于NCAR模式,如果强迫足够大,气候系统将会经历失控增暖。失控增暖的主要趋势并不是最初设想的正的水汽反馈增暖,至少在模式中,不只是“失控的温室效应”增暖,还有“失控的云反馈”增暖。     

太原气候变暖特征及主要极端天气气候事件变化研究

近45a来，太原平川和山区年平均气温为明显上升趋势，夜间增温是太原气候变暖的一个重要特征。1986年、1993年分别为山区和平川年平均气温转折年份，山区从1985年开始冬季平均气温发生突变。近45a来，太原年降水量呈减少趋势，主要是夏、秋季降水减少造成。在气候变暖的背景下，太原平川和山区年暴雨日数变化平稳，高温和春旱发生频次在增加，山区夏旱也呈缓慢增加趋势；太原山区霜期明显缩短，初霜在推迟，终霜在提前。     

The Influence of Climate Warming on Soil Frost on Snow-Free Surfaces in Finland

The influence of the predicted climate warming on soil frost conditions in Finland was studied using a climate scenario based on a Hadley Centre (U.K.) global ocean-atmosphere general circulation model (HadCM2) run. HadCM2 results were dynamically downscaled to the regional level using the regional climate model at the Rossby Centre (Sweden). The future period this study focuses on is the end of the 21st century. The study was limited to ground surface conditions in which snow has been removed. The predicted air temperature rise was interpreted in terms of changes in soil frost conditions using an empirical dependence that was found between measured soil frost depths and the sum of daily mean air temperatures calculated from the beginning of the freezing period. On average the annual maximum soil frost depth will decrease in southern and central Finland from the present approx. 100–150 cm by about 50 cm. In northern Finland the change will be from depths of about 200–300 cm to about 100–200 cm depending on station. The annual maximum soil frost depth in the future would thus be about the same in northern Finland as it is in the current climate in southern Finland. In southern Finland after about 100 years the ground will seldom be frozen in December and even in January there will be no soil frost in about half of the years. In Central and northern Finland the probability of completely unfrozen ground in December–March is very small, even in the future.     

气候变暖对新安水资源的影响

选取气温、降水和蒸发这3个对水资源影响最大的气象因子,分析其变化特点及其与新安水资源变化的相关性,结果表明,气温升高和降水减少是影响新安水资源的重要因素,其中降水是最重要的影响因素.结合他人研究成果,对该地区水资源可持续利用提出对策建议.     

Impact of Global Oceanic Warming on Winter Eurasian Climate

In the 20 th century, Eurasian warming was observed and was closely related to global oceanic warming(the first leading rotated empirical orthogonal function of annual mean sea surface temperature over the period 1901–2004). Here, large-scale patterns of covariability between global oceanic warming and circulation anomalies are investigated based on NCEP–NCAR reanalysis data. In winter, certain dominant features are found, such as a positive pattern of the North Atlantic Oscillation(NAO), low-pressure anomalies over northern Eurasia, and a weakened East Asian trough. Numerical experiments with the CAM3.5, CCM3 and GFDL models are used to explore the contribution of global oceanic warming to the winter Eurasian climate. Results show that a positive NAO anomaly, low-pressure anomalies in northern Eurasia, and a weaker-than-normal East Asian trough are induced by global oceanic warming. Consequently, there are warmer winters in Europe and the northern part of East Asia. However, the Eurasian climate changes differ slightly among the three models. Eddy forcing and convective heating from those models may be the reason for the different responses of Eurasian climate.     

雁山楝树物候对气候变暖的响应

对桂北地区雁山气温等气候要素与楝树5个物候期的多年同步观测资料的对比分析,结果表明:(1)桂林雁山近34a来年平均气温呈显著上升趋势,特别是1997年以来增温特明显,在增温过程中以春季增温为主,冬季和秋季增温次之,夏季呈弱降温趋势;(2)近10a来雁山楝树展叶盛期、开花盛期表现为一致的提前趋势,叶全变色期和落叶始期表现推迟的趋势,整个绿叶期延长,果成熟期表现推迟;(3)2月平均气温(T2)和1～3月均温(T1-3)是影响楝树展叶盛期、开花盛期的主要气候因子;(4)楝树物候变化是植物对气候变暖的响应。     

气候变暖对水稻生育期影响的情景分析

温度是影响作物发育速度的基本因子之一,温度的高低决定生育期的长短。利用全国水稻生态试验资料,分析了不同气候带的水稻生育期与温度的关系。结果指出,水稻生育期平均气温升高1℃,生育期日数平均缩短7.6日。温室效应使气温升高1～4℃,将导致我国各地水稻的一季稻和早稻生育期缩短;东部地区目前的生育期等日期线北移;东北地区北移1～5个纬度;黄淮地区北移3～6个纬度。通过调整种植季节,选用合适的水稻生态类型,以水调温措施,可以减少生育期缩短的日数。     

Detectability of Summer Dryness Caused by Greenhouse Warming

This study investigates the temporal and spatial variation of soil moisture associated with global warming as simulated by long-term integrations of a coupled ocean-atmosphere model conducted earlier. Starting from year 1765, integrations of the coupled model for 300 years were performed for three scenarios: increasing greenhouse gases only, increasing sulfate-aerosol loading only and the combination of both radiative forcings. The integration with the combined radiative forcings reproduces approximately the observed increases of global mean surface air temperature during the 20th century. Analysis of this integration indicates that both summer dryness and winter wetness occur in middle-to-high latitudes of North America and southern Europe. These features were identified in earlier studies. However, in the southern part of North America where the percentage reduction of soil moisture during summer is quite large, soil moisture is decreased for nearly the entire annual cycle in response to greenhouse warming. A similar observation applies to other semi-arid regions in subtropical to middle latitudes such as central Asia and the area surrounding the Mediterranean Sea. On the other hand, annual mean runoff is greatly increased in high latitudes because of increased poleward transport of moisture in the warmer model atmosphere. An analysis of the central North American and southern European regions indicates that the time when the change of soil moisture exceeds one standard deviation about the control integration occurs considerably later than that of surface air temperature for a given experiment because the ratio of forced change to natural variability is much smaller for soil moisture compared with temperature. The corresponding lag time for runoff change is even greater than that of either precipitation or soil moisture for the same reason. Also according to the above criterion, the inclusion of the effect of sulfate aerosols in the greenhouse warming experiment delays the noticeable change of soil moisture by several decades. It appears that observed surface air temperature is a better indicator of greenhouse warming than hydrologic quantities such as precipitation, runoff and soil moisture. Therefore, we are unlikely to notice definitive CO₂-induced continental summer dryness until several decades into the 21st century.     

气候变暖对我国社会经济的影响

全球气候变暖目前已经成为人类越来越关注的社会问题。气象观测结果表明，2007年2月，中亚和东亚、欧洲大部、白令海峡及其附近地区、阿尔及利亚和澳大利亚大部气温明显偏高2℃以上，其中东亚部分地区和白令海峡附近地区显著偏高4℃～9℃。2006年冬季，我国大部地区气温较常年同期（-4．3℃）偏高1．9℃，为历史同期第二高值，其中黑龙江、吉林的部分地区偏高达4℃～6℃，