The Agriculture,Forestry,and Other Land Use(AFOLU)sector is critical in achieving the goal of limiting global average temperature to well below 2°C above pre-industrial levels.However,a knowledge gap remains rega...The Agriculture,Forestry,and Other Land Use(AFOLU)sector is critical in achieving the goal of limiting global average temperature to well below 2°C above pre-industrial levels.However,a knowledge gap remains regarding whether current ambitions can achieve the temperature targets.This study established a 4-step analytical framework to evaluate the mitigation targets,pledged ambitions,and implementation within the AFOLU sector based on the Nationally Determined Contributions and Long-term Low Emissions Development Strategies of the typical 80 countries.The results indicated that 58 countries set quantitative mitigation targets,including emission and activity targets.Twenty-six countries established emission targets for 2030,representing a median emission reduction ambition of 25.5%.AFOLU's emissions are expected to be reduced by 1,305.26 Mt CO_(2)-eq year^(-1),approximately 16%of total emissions,if unconditional emission targets are met,and 2,230.20 Mt CO_(2)-eq year^(-1),approximately 27%of total emissions,if conditional emission targets are met.Compared to emission targets,activity targets lead to higher ambitions,with a 2.52 Gt CO_(2)-eq year^(-1)economic potential,approximately 30%of total emissions,and a 4.41 Gt CO_(2)-eq year^(-1)technical potential,approximately 53%of total emissions.The identified finance needs are at least 842.98 billion USD by 2030,far exceeding current investment levels,yet still falls short of achieving the temperature targets.Currently,51 of the 58 countries have proposed policy instruments to help realize their targets,with regulatory and cognitive instruments playing fundamental roles.However,ambiguous,incoherent,and inadequate policy information leads to uncertainties regarding the feasibility and effectiveness of mitigation ambitions and their implementation.展开更多
If urban sprawl is to be avoided in China in the next ten years, it is not only crucial to understand the overall history, current status, and future trends of urban expansion there, but also these differences, and th...If urban sprawl is to be avoided in China in the next ten years, it is not only crucial to understand the overall history, current status, and future trends of urban expansion there, but also these differences, and this is presently lacking. In this study, remotely sensed images with approximately 30 m spatial resolution were used to quantitatively assess the spatial and temporal patterns of urban expansion of 60 Chinese cities(1973–2013). Urban-expansion-process curves of the cities studied were drawn using annual expansion area as an indicator. Curve similarity analysis generated four basic process modes of urban expansion in China. These included cities that: 1) peaked around 2004 and then decelerated; 2) peaked around 2010 and then decelerated; 3) showed sustained acceleration, and 4) showed continued deceleration. Four basic process modes represented cities under different levels of development stage. Geographic location was found to be the most related characteristic to urban expansion process. Regional development policies at the national level in each region also showed highly temporal consistency with fluctuation characteristics of urban expansion process. Urban characteristic such as population size and administrative level were not found to be significantly related to urban expansion-process modes. Understanding the basic process-mode categories well is extremely important for future regional-balance planning and development of macroeconomic policies.展开更多
文摘三氯生(triclosan,TCS)和三氯卡班(triclocarban,TCC)是2种高效广谱抗菌剂,均具有胚胎毒性、内分泌干扰性和生殖毒性,并可能引发癌症、DNA损伤和不良妊娠结局等,是目前一类广泛关注的新污染物。美国食品与药品监督管理局(US FDA)于2016年已禁止含有TCS和TCC等抑菌剂的非处方抗菌洗浴产品进入市场,而目前在我国其为化妆品准用防腐剂,允许限量使用,且皂类产品不在限制范围内。TCS和TCC作为新兴的外源性化学污染物能够随生活污水的排放进入自然环境,对我国本土水生生物、生态安全和人身健康构成了潜在威胁。为探究TCS和TCC对我国本土鱼种稀有鮈鲫(Gobiocypris rarus)长期暴露及4个不同发育阶段(胚胎期、卵黄囊吸收阶段、仔鱼及幼鱼阶段)的毒性效应,本研究将稀有鮈鲫的受精卵暴露于TCS和TCC中,直至孵化后60 d(60 days post hatch,60 dph),试验过程中监测胚胎期的孵化率,卵黄囊吸收阶段、仔鱼及幼鱼阶段的成活率,长期暴露过程中的生长情况、性分化及内分泌干扰效应等多个指标。研究结果显示,在胚胎期,6.25~100μg·L^(-1)的TCS和0.938~15μg·L^(-1)的TCC对稀有鮈鲫的胚胎孵化率没有显著的毒性效应。在仔鱼阶段,6.25~100μg·L^(-1)的TCS和0.938~15μg·L^(-1)的TCC暴露组30 dph成活率的最高无可观察效应浓度分别为100μg·L^(-1)和0.938μg·L^(-1),根据我国国家标准,TCC对水生环境的危害可判定为长期慢性类别1,而TCS由于试验中的最高浓度未达到1 mg·L^(-1),无法作出明确的判断,但能判断其对水生环境的危害为非长期慢性类别1。在幼鱼阶段,6.25~100μg·L^(-1)的TCS和0.938~15μg·L^(-1)的TCC均对雌性及雄性稀有鮈鲫体内卵黄蛋白原具有一定的诱导作用,但在性分化上没有显著影响。在胚后发育过程中,通过长期暴露,6.25~100μg·L^(-1)的TCS对稀有鮈鲫体质量有显著毒性效应,随TCS浓度的升高,稀有鮈鲫体质量逐渐降低,TCS对稀有鮈鲫体质量具有抑制作用;0.938~15μg·L^(-1)的TCC对稀有鮈鲫体质量及体长等生长均无显著影响。此外,研究发现稀有鮈鲫在不同发育阶段的毒性效应存在差异,稀有鮈鲫胚胎期的耐受力明显高于胚后发育阶段,卵黄囊吸收阶段及仔鱼阶段的耐受力低于幼鱼阶段。可见,当更多的生命阶段被包括在一个测试中,能够通过较少的试验动物,获得较多的毒性终点,且测试中不同生命阶段的毒性效应来自同一批试验动物,使不同生命阶段的试验结果更具可比性。
基金funded by the National Key R&D Program of China(2023YFE0113000)key projects of the National Social Science Fund of China(22AZD098)
文摘The Agriculture,Forestry,and Other Land Use(AFOLU)sector is critical in achieving the goal of limiting global average temperature to well below 2°C above pre-industrial levels.However,a knowledge gap remains regarding whether current ambitions can achieve the temperature targets.This study established a 4-step analytical framework to evaluate the mitigation targets,pledged ambitions,and implementation within the AFOLU sector based on the Nationally Determined Contributions and Long-term Low Emissions Development Strategies of the typical 80 countries.The results indicated that 58 countries set quantitative mitigation targets,including emission and activity targets.Twenty-six countries established emission targets for 2030,representing a median emission reduction ambition of 25.5%.AFOLU's emissions are expected to be reduced by 1,305.26 Mt CO_(2)-eq year^(-1),approximately 16%of total emissions,if unconditional emission targets are met,and 2,230.20 Mt CO_(2)-eq year^(-1),approximately 27%of total emissions,if conditional emission targets are met.Compared to emission targets,activity targets lead to higher ambitions,with a 2.52 Gt CO_(2)-eq year^(-1)economic potential,approximately 30%of total emissions,and a 4.41 Gt CO_(2)-eq year^(-1)technical potential,approximately 53%of total emissions.The identified finance needs are at least 842.98 billion USD by 2030,far exceeding current investment levels,yet still falls short of achieving the temperature targets.Currently,51 of the 58 countries have proposed policy instruments to help realize their targets,with regulatory and cognitive instruments playing fundamental roles.However,ambiguous,incoherent,and inadequate policy information leads to uncertainties regarding the feasibility and effectiveness of mitigation ambitions and their implementation.
基金Under the auspices of National Natural Science Foundation of China(No.41201443,41101148)Strategic Planning Program in the Thirteenth Five-Year Plan of Institute of Remote Sensing and Digital Earth,Chinese Academy of Sciences(No.Y4SG0100CX)
文摘If urban sprawl is to be avoided in China in the next ten years, it is not only crucial to understand the overall history, current status, and future trends of urban expansion there, but also these differences, and this is presently lacking. In this study, remotely sensed images with approximately 30 m spatial resolution were used to quantitatively assess the spatial and temporal patterns of urban expansion of 60 Chinese cities(1973–2013). Urban-expansion-process curves of the cities studied were drawn using annual expansion area as an indicator. Curve similarity analysis generated four basic process modes of urban expansion in China. These included cities that: 1) peaked around 2004 and then decelerated; 2) peaked around 2010 and then decelerated; 3) showed sustained acceleration, and 4) showed continued deceleration. Four basic process modes represented cities under different levels of development stage. Geographic location was found to be the most related characteristic to urban expansion process. Regional development policies at the national level in each region also showed highly temporal consistency with fluctuation characteristics of urban expansion process. Urban characteristic such as population size and administrative level were not found to be significantly related to urban expansion-process modes. Understanding the basic process-mode categories well is extremely important for future regional-balance planning and development of macroeconomic policies.
