Embodied Greenhouse Gas Emissions in Diets

Changing food consumption patterns and associated greenhouse gas (GHG) emissions have been a matter of scientific debate for decades. The agricultural sector is one of the major GHG emitters and thus holds a large potential for climate change mitigation through optimal management and dietary changes. We assess this potential, project emissions, and investigate dietary patterns and their changes globally on a per country basis between 1961 and 2007. Sixteen representative and spatially differentiated patterns with a per capita calorie intake ranging from 1,870 to 3,400 kcal/day were derived. Detailed analyses show that low calorie diets are decreasing worldwide, while in parallel diet composition is changing as well: a discernable shift towards more balanced diets in developing countries can be observed and steps towards more meat rich diets as a typical characteristics in developed countries. Low calorie diets which are mainly observable in developing countries show a similar emission burden than moderate and high calorie diets. This can be explained by a less efficient calorie production per unit of GHG emissions in developing countries. Very high calorie diets are common in the developed world and exhibit high total per capita emissions of 3.7–6.1 kg CO_2eq./day due to high carbon intensity and high intake of animal products. In case of an unbridled demographic growth and changing dietary patterns the projected emissions from agriculture will approach 20 Gt CO_2eq./yr by 2050.     

低碳经济计量模式

首先对"低碳经济"进行了讨论,进而提出了"碳循环经济"概念;对现有碳计量进行研究,提出了相应改进计算公式:碳绩效和碳经济密度。最后,对碳责任分担进行了探讨,提出了发达国家和发展中国家"责任共担、区别对待"的碳责任担负的计算模式。     

中国区域间隐含碳排放转移

利用投入产出模型,对消费视角下碳排放的核算方法及国际贸易中隐含碳排放转移的研究是当前国际学术界碳排放研究的焦点问题之一。在梳理国内外相关研究进展的基础上,利用区域间投入产出模型构建了区域间隐含碳排放转移的核算方法,并计算了1997年和2007年中国8个主要区域间隐含的碳排放转移及其变化。结果显示,不管是在规模还是空间上,中国区域间隐含碳排放转移都发生了很大变化,总体上呈现向西部地区延伸的趋势,尤其是西北地区成为最大的碳排放承接区域。而京津和东南沿海地区始终是主要的碳转出地区,尤其是东南沿海地区因出口而导致的碳排放向中西部地区转移的增加最为明显。因此,调整东部地区的出口结构,优化投资和消费结构,避免落后淘汰产能通过区域转移进一步发展,提高节能技术的应用是我国节能减排工作的重要内容。     

排放与森林碳汇作用下云南省碳净排放量估计

以云南省为例,用马尔科夫链计算能源结构,在经济增长模型基础上基于动态最优化理论估计能源消费碳排放,并基于CO₂FIX模型计算云南省森林碳汇,预测在能源消费碳排放和森林碳汇共同作用下的从2008到2050年碳净排放量。研究发现云南省能源消费碳排放量和碳净排放量曲线都呈"倒U"型,在2035年达到高峰,高峰值分别为和129.71 MtC和118.89 MtC;在森林碳汇中,原有森林的碳汇作用在现在和未来一段时间内处于主导地位,但新造林有着巨大的碳汇潜力,所以在保护原有森林的同时要植树造林,从生态学角度抵消碳排放;森林碳汇只能减少小部分碳排放,更主要的是改善云南省的能源结构,加快技术进步速度,开发水电等新能源,从根本上减少温室气体的排放。     

Biotechnology and sustainable development in sub-Saharan Africa

Whether development is defined by the long-standing economic parameter of per capita gross national product (GNP) or by the newly introduced Human Development Index (HDI), which is not based exclusively on per capita GNP, the countries of sub-Saharan Africa rank at or near the bottom of the developing world. Agriculture and agro-based processing are the mainstays of the economies of the majority of these countries. Because of this, and also because many of the diseases endemic in these countries are communicable, the application of modern biotechnology (including genetic engineering, tissue culture and monoclonal antibody technology) and related biotechnologies could play an important part in creating sustainable development in the region. There is, therefore, an urgent need to train more of the region's indigenous citizens, and to equip more laboratories, in modern biotechnology. It is suggested that, in order to accelerate the harnessing of the fruits of biotechnology, more countries in the region should affiliate with the International Centre for Genetic Engineering and Biotechnology (ICGEB). It is further suggested that a regional equivalent of the ICGEB be built and the services of non-governmental biotechnology organizations used.The author is with Nnamdi Azikiwe University, P. M. B. 5025, Awka, Nigeria. Address correspondence to P. M. B. 1457, Enugu, Nigeria     

世界主要国家耕地动态变化及其影响因素

在世界人口持续攀升、全球耕地面积不断减少的背景下,探讨世界主要国家耕地变化其影响因素,对于分析预测未来世界耕地变化趋势、研究世界粮食安全具有积极意义。选择2050年人口过亿的17个国家和耕地面积排名前10的国家为研究对象,在分析1961—2007年耕地总量变化、人均耕地变化的基础上,探讨了耕地变化影响因素。研究结果表明,从20世纪60年代到2007年间的不同时期内,有越来越多的国家表现出耕地减少趋势,而人均耕地面积减少的国家个数高达90%以上。满足人口消费需求、城市化与经济发展是大多数国家耕地总量变化的主要动力;而人口快速增长、城市化则是导致许多国家人均耕地显著减少的重要原因。     

中国能源消费碳排放的时空特征

选择联合国政府间气候变化专门委员会(IPCC)的部门方法和8大类能源,采用1990年至2009年的中国能源统计数据,按照自下而上的思路,对我国各省区的碳排放量进行估算,并从碳排放量、碳排放强度、人均碳排放量和碳排放密指标出发,深入分析了各省区碳排放的时空特征差异。以期对国内碳排放的时空特征分析,有助于决策者和能源分析家提高节能减排政策制定的有效性。     

湖南市域化石能源消费碳排放时空格局及驱动因素

研究碳排放时空格局演变及其影响因素对指导碳减排具有重要意义。利用2008—2013年湖南省14地市规模以上工业企业终端能源消费数据,运用IPCC提供的参考方法和对数平均迪氏指标分解模型(Logarithmic Mean Divisia Index,LMDI)对湖南市域碳排放量、人均碳排放量、碳排放强度的时空格局及碳排放量变化的影响因素进行了研究。结果表明:1)2008—2013年湖南市域碳排放量随时间变化趋势不一,大致呈3种类型变化;累积碳排放量居前3位的市域依次是娄底、岳阳和湘潭,三者累积碳排放量占全省同期的48.92%,而吉首、张家界和怀化3市的累积碳排放量合计仅占全省的2.59%。2)湖南市域能源消费碳排放量、人均碳排放量存在相似的空间差异,二者均表现为东高西低的格局,且具有较强的相关性,碳排放量高的市域,人均碳排放量也较高;2008—2013年湖南市域碳排放强度呈下降趋势,属于低强度区的市域由2008年的4个增加到2013年的7个,碳排放强度的空间分布与市域产业类型有关。3)能源结构、能源强度对碳排放的增长主要起抑制作用,但能源结构的贡献很小,碳排放量的降低主要是由能源强度引起的;经济发展是碳排放增长的最主要因素,在2008—2010年和2011—2013年两个时段其累积贡献值分别为74.285和27.579;人口规模对碳排放的驱动较小,在2011—2013年对碳排放增加产生的累积贡献值仅为2.252。湖南当前及未来碳减排的重点是加快发展清洁能源与提高能效并重,优化能源结构和促进产业结构升级,从战略层面促进湖南"四大区域"协调发展。     

Review of accounting for carbon dioxide emissions from tourism at different spatial scales

Carbon dioxide emission from tourism, as a focus of man-land relationship in tourism industry in the 21st century, is a vital index reflecting its effect on environment change. The article summarizes the contents of carbon dioxide emissions from tourism at different scales such as world, nation, region and unit. These results indicate that: (1) the accounting of the carbon dioxide emissions from tourism began from global and national scales at the end of the last century, then to regional and basic scales. (2) The Carbon dioxide emissions from tourism are mainly from high-developed countries and regions in terms of space, from the minority high-spending tourists in terms of behavior, from high-speed vehicles, high-grade accommodations and high-level tourism activities in terms of tourism element. The carbon dioxide emissions per capita of developing countries and regions are less than one tenth in developed countries and regions. As for the proportion of total emission, tourism transportation accounts for the largest, generally more than 65%, followed by accommodation, and the last is tourism activity. (3) Based on the systemic analysis of these coefficients of accounting carbon dioxide emissions in tourism, the paper indicates that there are progresses in the consistency of coefficients at global scale and diversity of coefficients at national, regional and unit scales, while the coefficients of developed countries and regions are higher than those of developing countries and regions. In addition, some recommendations including coefficients have given to China.     

Global and regional importance of the tropical peatland carbon pool

Accurate inventory of tropical peatland is important in order to (a) determine the magnitude of the carbon pool; (b) estimate the scale of transfers of peat‐derived greenhouse gases to the atmosphere resulting from land use change; and (c) support carbon emissions reduction policies. We review available information on tropical peatland area and thickness and calculate peat volume and carbon content in order to determine their best estimates and ranges of variation. Our best estimate of tropical peatland area is 441 025 km² (～11% of global peatland area) of which 247 778 km² (56%) is in Southeast Asia. We estimate the volume of tropical peat to be 1758 Gm³ (～18–25% of global peat volume) with 1359 Gm³ in Southeast Asia (77% of all tropical peat). This new assessment reveals a larger tropical peatland carbon pool than previous estimates, with a best estimate of 88.6 Gt (range 81.7–91.9 Gt) equal to 15–19% of the global peat carbon pool. Of this, 68.5 Gt (77%) is in Southeast Asia, equal to 11–14% of global peat carbon. A single country, Indonesia, has the largest share of tropical peat carbon (57.4 Gt, 65%), followed by Malaysia (9.1 Gt, 10%). These data are used to provide revised estimates for Indonesian and Malaysian forest soil carbon pools of 77 and 15 Gt, respectively, and total forest carbon pools (biomass plus soil) of 97 and 19 Gt. Peat carbon contributes 60% to the total forest soil carbon pool in Malaysia and 74% in Indonesia. These results emphasize the prominent global and regional roles played by the tropical peat carbon pool and the importance of including this pool in national and regional assessments of terrestrial carbon stocks and the prediction of peat‐derived greenhouse gas emissions.     

Global environmental costs of China's thirst for milk

China has an ever‐increasing thirst for milk, with a predicted 3.2‐fold increase in demand by 2050 compared to the production level in 2010. What are the environmental implications of meeting this demand, and what is the preferred pathway? We addressed these questions by using a nexus approach, to examine the interdependencies of increasing milk consumption in China by 2050 and its global impacts, under different scenarios of domestic milk production and importation. Meeting China's milk demand in a business as usual scenario will increase global dairy‐related (China and the leading milk exporting regions) greenhouse gas (GHG) emissions by 35% (from 565 to 764 Tg CO_2eq) and land use for dairy feed production by 32% (from 84 to 111 million ha) compared to 2010, while reactive nitrogen losses from the dairy sector will increase by 48% (from 3.6 to 5.4 Tg nitrogen). Producing all additional milk in China with current technology will greatly increase animal feed import; from 1.9 to 8.5 Tg for concentrates and from 1.0 to 6.2 Tg for forage (alfalfa). In addition, it will increase domestic dairy related GHG emissions by 2.2 times compared to 2010 levels. Importing the extra milk will transfer the environmental burden from China to milk exporting countries; current dairy exporting countries may be unable to produce all additional milk due to physical limitations or environmental preferences/legislation. For example, the farmland area for cattle‐feed production in New Zealand would have to increase by more than 57% (1.3 million ha) and that in Europe by more than 39% (15 million ha), while GHG emissions and nitrogen losses would increase roughly proportionally with the increase of farmland in both regions. We propose that a more sustainable dairy future will rely on high milk demanding regions (such as China) improving their domestic milk and feed production efficiencies up to the level of leading milk producing countries. This will decrease the global dairy related GHG emissions and land use by 12% (90 Tg CO_2eq reduction) and 30% (34 million ha land reduction) compared to the business as usual scenario, respectively. However, this still represents an increase in total GHG emissions of 19% whereas land use will decrease by 8% when compared with 2010 levels, respectively.     

Climate Change and Global Health: Quantifying a Growing Ethical Crisis

Climate change, as an environmental hazard operating at the global scale, poses a unique and “involuntary exposure” to many societies, and therefore represents possibly the largest health inequity of our time. According to statistics from the World Health Organization (WHO), regions or populations already experiencing the most increase in diseases attributable to temperature rise in the past 30 years ironically contain those populations least responsible for causing greenhouse gas warming of the planet. Average global carbon emissions approximate one metric ton per year (tC/yr) per person. In 2004, United States per capita emissions neared 6 tC/yr (with Canada and Australia not far behind), and Japan and Western European countries range from 2 to 5 tC/yr per capita. Yet developing countries’ per capita emissions approximate 0.6 tC/yr, and more than 50 countries are below 0.2 tC/yr (or 30-fold less than an average American). This imbalance between populations suffering from an increase in climate-sensitive diseases versus those nations producing greenhouse gases that cause global warming can be quantified using a “natural debt” index, which is the cumulative depleted CO₂ emissions per capita. This is a better representation of the responsibility for current warming than a single year’s emissions. By this measure, for example, the relative responsibilities of the U.S. in relation to those of India or China is nearly double that using an index of current emissions, although it does not greatly change the relationship between India and China. Rich countries like the U.S. have caused much more of today’s warming than poor ones, which have not been emitting at significant levels for many years yet, no matter what current emissions indicate. Along with taking necessary measures to reduce the extent of global warming and the associated impacts, society also needs to pursue equitable solutions that first protect the most vulnerable population groups; be they defined by demographics, income, or location. For example, according to the WHO, 88% of the disease burden attributable to climate change afflicts children under age 5 (obviously an innocent and “nonconsenting” segment of the population), presenting another major axis of inequity. Not only is the health burden from climate change itself greatest among the world’s poor, but some of the major mitigation approaches to reduce the degree of warming may produce negative side effects disproportionately among the poor, for example, competition for land from biofuels creating pressure on food prices. Of course, in today’s globalized world, eventually all nations will share some risk, but underserved populations will suffer first and most strongly from climate change. Moreover, growing recognition that society faces a nonlinear and potentially irreversible threat has deep ethical implications about humanity’s stewardship of the planet that affect both rich and poor.     

Bioethics and Its Gatekeepers: Does Institutional Racism Exist in Leading Bioethics Journals?

Who are the gatekeepers in bioethics? Does editorial bias or institutional racism exist in leading bioethics journals? We analyzed the composition of the editorial boards of 14 leading bioethics journals by country. Categorizing these countries according to their Human Development Index (HDI), we discovered that approximately 95 percent of editorial board members are based in (very) high-HDI countries, less than 4 percent are from medium-HDI countries, and fewer than 1.5 percent are from low-HDI countries. Eight out of 14 leading bioethics journals have no editorial board members from a medium- or low-HDI country. Eleven bioethics journals have no board members from low-HDI countries. This severe underrepresentation of bioethics scholars from developing countries on editorial boards suggests that bioethics may be affected by institutional racism, raising significant questions about the ethics of bioethics in a global context.     

Can carbon emissions from tropical deforestation drop by 50% in 5 years?

Halving carbon emissions from tropical deforestation by 2020 could help bring the international community closer to the agreed goal of <2 degree increase in global average temperature change and is consistent with a target set last year by the governments, corporations, indigenous peoples' organizations and non‐governmental organizations that signed the New York Declaration on Forests (NYDF). We assemble and refine a robust dataset to establish a 2001–2013 benchmark for average annual carbon emissions from gross tropical deforestation at 2.270 Gt CO₂ yr^?1. Brazil did not sign the NYDF, yet from 2001 to 2013, Brazil ranks first for both carbon emissions from gross tropical deforestation and reductions in those emissions – its share of the total declined from a peak of 69% in 2003 to a low of 20% in 2012. Indonesia, an NYDF signatory, is the second highest emitter, peaking in 2012 at 0.362 Gt CO₂ yr^?1 before declining to 0.205 Gt CO₂ yr^?1 in 2013. The other 14 NYDF tropical country signatories were responsible for a combined average of 0.317 Gt CO₂ yr^?1, while the other 86 tropical country non‐signatories were responsible for a combined average of 0.688 Gt CO₂ yr^?1. We outline two scenarios for achieving the 50% emission reduction target by 2020, both emphasizing the critical role of Brazil and the need to reverse the trends of increasing carbon emissions from gross tropical deforestation in many other tropical countries that, from 2001 to 2013, have largely offset Brazil's reductions. Achieving the target will therefore be challenging, even though it is in the self‐interest of the international community. Conserving rather than cutting down tropical forests requires shifting economic development away from a dependence on natural resource depletion toward recognition of the dependence of human societies on the natural capital that tropical forests represent and the goods and services they provide.     

Emission scenario of non-CO2 gases from energy activities and other sources in China

This paper gives a quantitative analysis on the non-CO2 emissions related to energy demand, energy activities and land use change of six scenarios with different development pattern in 2030 and 2050 based on IPAC emission model. The various mitigation technologies and policies are assessed to understand the corresponding non-CO2 emission reduction effect. The research shows that the future non-CO2 emissions of China will grow along with increasing energy demand, in which thermal power and transportation will be the major emission and mitigation sectors. During the cause of future social and economic development, the control and mitigation of non-CO2 emissions is a problem as challenging and pressing as that of CO2 emissions. This study indicates that the energy efficiency improvement, renewable energy, advanced nuclear power generation, fuel cell, coal-fired combined cycle, clean coal and motor vehicle emission control technologies will contribute to non-CO2 emissions control and mitigation.     

Emission scenario of non-CO2 gases from energy activities and other sources in China

This paper gives a quantitative analysis on the non-CO2 emissions related to energy demand, energy activities and land use change of six scenarios with different development pattern in 2030 and 2050 based on IPAC emission model. The various mitigation technologies and policies are assessed to understand the corresponding non-CO2 emission reduction effect. The research shows that the future non-CO2 emissions of China will grow along with increasing energy demand, in which thermal power and transportation will be the major emission and mitigation sectors. During the cause of future social and economic development, the control and mitigation of non-CO2 emissions is a problem as challenging and pressing as that of CO2 emissions.This study indicates that the energy efficiency improvement, renewable energy, advanced nuclear power generation, fuel cell, coal-fired combined cycle, clean coal and motor vehicle emission control technologies will contribute to non-CO2 emissions control and mitigation.     

Methane emission from global livestock sector during 1890–2014: Magnitude,trends and spatiotemporal patterns

Human demand for livestock products has increased rapidly during the past few decades largely due to dietary transition and population growth, with significant impact on climate and the environment. The contribution of ruminant livestock to greenhouse gas (GHG) emissions has been investigated extensively at various scales from regional to global, but the long‐term trend, regional variation and drivers of methane (CH₄) emission remain unclear. In this study, we use Intergovernmental Panel on Climate Change (IPCC) Tier II guidelines to quantify the evolution of CH₄ emissions from ruminant livestock during 1890–2014. We estimate that total CH₄ emissions in 2014 was 97.1 million tonnes (MT) CH₄ or 2.72 Gigatonnes (Gt) CO₂‐eq (1 MT = 10¹² g, 1 Gt = 10¹⁵ g) from ruminant livestock, which accounted for 47%–54% of all non‐CO₂ GHG emissions from the agricultural sector. Our estimate shows that CH₄ emissions from the ruminant livestock had increased by 332% (73.6 MT CH₄ or 2.06 Gt CO₂‐eq) since the 1890s. Our results further indicate that livestock sector in drylands had 36% higher emission intensity (CH₄ emissions/km²) compared to that in nondrylands in 2014, due to the combined effect of higher rate of increase in livestock population and low feed quality. We also find that the contribution of developing regions (Africa, Asia and Latin America) to the total CH₄ emissions had increased from 51.7% in the 1890s to 72.5% in the 2010s. These changes were driven by increases in livestock numbers (LU units) by up to 121% in developing regions, but decreases in livestock numbers and emission intensity (emission/km²) by up to 47% and 32%, respectively, in developed regions. Our results indicate that future increases in livestock production would likely contribute to higher CH₄ emissions, unless effective strategies to mitigate GHG emissions in livestock system are implemented.     

“双碳”目标下闽三角碳排放脱钩状态及驱动机制分析

快速城市化背景下,建设低碳城市群是实现"双碳"目标的最佳方式。在碳排放核算的基础上,使用Tapio脱钩模型和LMDI方法对闽三角以及厦门、漳州和泉州的脱钩状态和碳排放的驱动机制进行了研究。主要结论如下：（1）2005-2017年闽三角碳排放和人均碳排放均持续增加,二者有相同的变化趋势。闽三角的工业中心泉州有最高的碳排放和人均碳排放。发展型城市漳州碳排放最低,但碳排放和人均碳排放增长率均最高。服务型城市厦门碳排放增长率最低。（2）闽三角的脱钩状态逐渐改善,平均脱钩系数为1.03,脱钩状态为扩张性连接。厦门、漳州和泉州的平均脱钩系数分别为0.45、2.70和1.10,3个城市分别以弱脱钩、扩张负脱钩和扩张性连接状态为主。（3）人均GDP和人口规模是闽三角碳排放的正向因素,能源结构和能源强度是负向因素。正向因素的贡献在下降,负向因素的贡献在升高。人均GDP和能源结构分别对漳州和厦门碳排放有最强的促进和抑制效应。能源强度对3个城市碳排放变化的效应不同。（4）人口扩张促进碳排放增加,使碳排放与经济发展无法脱钩。人口规模对闽三角碳减排无脱钩努力。能源结构优化和能源强度下降有助于碳排放与经济发展脱钩,是闽三角碳减排的强脱钩努力和弱脱钩努力。能源强度对泉州碳减排无脱钩努力。优化能源结构是闽三角实现碳减排和"双碳"目标的关键。已经脱钩的厦门宜尽早制定碳达峰行动计划,引领闽三角的碳达峰行动。漳州可通过升级产业结构实现减排。泉州必须提升能源效率才能降低碳排放。     

杭州市公交车油改电项目碳排放效益核算

以减少碳排放为核心的应对气候变化行动已成为全球趋势,中国政府积极践行减少碳排放的国际承诺,出台多项鼓励新能源的政策措施,其中包括对新能源产业的补偿以及将燃油汽车改装为电动汽车。但是这些政策的实施效果并不太清楚。举例来说,煤电为主的供电类型极大削弱了碳减排的效果,充电桩等配套基础设施建设和旧车报废等过程还会产生额外碳排放,不同城市之间的这些情况差别也较大。因此,城市层面生命周期尺度上的电动车碳减排效果尚未明确。基于生命周期理论,以杭州市为例,在构建公交车生命周期模型下分别核算纯电动和柴油车生命周期碳排放量,并在基准情景、低碳情景和强化低碳情景下进行公交车油改电碳排模拟。研究结果表明:(1)杭州市单辆纯电动和柴油公交车生命周期CO2排放量分别为1103.237t和1401.319t,减排比例达21.27%。其中,电力生产约占纯电动车生命周期碳排量74.10%,柴油生产与消耗约占柴油车生命周期碳排量86.96%;(2)目前杭州市在营运的2312辆纯电动公交车生命周期内(13年)碳减排总量约达到68.917万t,年均5.301万t;(3)在油改电过程中,纯电动公交车需运行约3.5年后才能相对柴油公交车真正起到碳减排效果;(4)在不同新煤电技术及能源结构优化下,2020、2035和2050年杭州市公交车油改电项目每辆车碳减排量将达到354.071—884.339t,年均27.236—68.026t,减排比例25.27%—63.11%,且2050年强化情景下纯公交车生命周期碳排量仅为当前纯电动公交车和柴油公交车的46.86%和36.89%,潜在碳减排效益显著。     

在我国开展林业碳汇项目的利弊分析

因为CO2等温室气体的增加导致的全球气候变暖严重影响了世界各国社会和经济的发展,而森林具有吸收大气中的CO2,减缓气候变暖的作用,因此2001年的《波恩政治协议》和《马拉喀什协定》同意将造林、再造林等林业碳汇项目作为第一承诺期合格的清洁发展机制(CDM)项目。目前,国际上此类活动已相继展开,而我国还未展开此类活动。为了给我国是否可以开展林业碳汇项目提供参考,文章对我国开展林业碳汇项目的利与弊进行了比较详细的分析和比较,认为可以在我国适当开展林业碳汇项目,以促进我国经济和社会的可持续发展,并进一步加强我国在国际上的地位。