Can the envisaged reductions of fossil fuel CO<Subscript>2</Subscript> emissions be detected by atmospheric observations?

The lower troposphere is an excellent receptacle, which integrates anthropogenic greenhouse gases emissions over large areas. Therefore, atmospheric concentration observations over populated regions would provide the ultimate proof if sustained emissions changes have occurred. The most important anthropogenic greenhouse gas, carbon dioxide (CO(2)), also shows large natural concentration variations, which need to be disentangled from anthropogenic signals to assess changes in associated emissions. This is in principle possible for the fossil fuel CO(2) component (FFCO(2)) by high-precision radiocarbon ((14)C) analyses because FFCO(2) is free of radiocarbon. Long-term observations of (14)CO(2) conducted at two sites in south-western Germany do not yet reveal any significant trends in the regional fossil fuel CO(2) component. We rather observe strong inter-annual variations, which are largely imprinted by changes of atmospheric transport as supported by dedicated transport model simulations of fossil fuel CO(2). In this paper, we show that, depending on the remoteness of the site, changes of about 7-26% in fossil fuel emissions in respective catchment areas could be detected with confidence by high-precision atmospheric (14)CO(2) measurements when comparing 5-year averages if these inter-annual variations were taken into account. This perspective constitutes the urgently needed tool for validation of fossil fuel CO(2) emissions changes in the framework of the Kyoto protocol and successive climate initiatives.     

Developing long-term strategies to reduce energy use and CO<Subscript>2</Subscript> emissions—analysis of three mitigation scenarios for iron and steel production in China

We perform a scenario analysis of three strategies for long-term energy savings and carbon dioxide (CO₂) emission reductions in iron and steel production in China, using a linear optimization modeling framework industry sector energy efficiency modeling (ISEEM). The modeling includes annual projections for one base scenario representing business-as-usual (BAU) and three additional scenarios representing different strategies to reduce annual energy use and CO₂ emissions from 2010 to 2050. Specifically, the three scenarios for cost-optimization modeling include changing the production share (PS), predefining emission reduction (ER) target, and stipulating carbon emission pricing (CP), respectively. While the three strategies are projected to result in similar annual energy savings by approximately 15 % compared to that of the BAU scenario in year 2050, the carbon emission pricing strategy brings about the highest annual energy savings in the medium term (e.g., 2025). In addition, adopting carbon emission pricing strategy will result in the highest emission reduction from BAU with much higher costs, i.e., by 20 % in 2025 and 41 % in 2050, while adopting either PS or ER strategies will result in a moderate level of emission reduction from BAU, i.e., by approximately 4 % in 2025 and 14 % in 2050. The analysis of China’s national strategies to reduce energy use and emissions provides important implications for global mitigation strategies.     

Mercury emissions and cycling in the coastal zone

ＩｎｔｒｏｄｕｃｔｉｏｎＭｅｒｃｕｒｙｌｅｖｅｌｓｉｎｍａｒｉｎｅａｎｄｆｒｅｓｈｗａｔｅｒｆｉｓｈｅｘｃｅｅｄｉｎｇｎａｔｉｏｎａｌａｎｄｉｎｔｅｒｎａｔｉｏｎａｌｐｕｂｌｉｃｈｅａｌｔｈｇｕｉｄｅｌｉｎｅｓａｒｅｃｏｍｍｏｎｔｏａｑｕａｔｉｃｓｙｓｔｅｍｓｉｎｂｏｔｈｈｅｍｉｓｐｈｅｒｅｓ,ａｎｄｉｎｓｅｔｔｉｎｇｓｒａｎｇｉｎｇｆｒｏｍｕｒｂａｎ/ｒｅｇｉｏｎａｌ/ｃｏａｓｔａｌｔｏｒｅｍｏｔｅｏｃｅａｎｉｃｅｎｖｉｒｏｎｓ (Ｅｉｓｌｅｒ,1981;Ｗｉｅｎｅｒ,1996;ＦａｒｏｅＩｓｌａｎｄｓＭｅｅ…     

Estimation of greenhouse gas emissions in China and the abatement measures

The major emission sources of carbon dioxide, methane, nitrous oxide and CFCs in China have been identified, and the emission trends has been estimated. Besides fossil fuel combustion, human respiration and biomass burning are important sources. Some feasible abatement measures on energy conservation, afforestation and biomass recycling have been discussed.     

An evaluation of mercury emissions from the chlor-alkali industry in China

1　ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｃｈｌｏｒｉｎｅ ａｌｋａｌｉｉｎｄｕｓｔｒｙｉｓｏｎｅｏｆｔｈｅｓｕｂｓｔａｎｔｉａｌｐａｒｔｓｏｆｔｈｅｃｈｅｍｉｃａｌｉｎｄｕｓｔｒｙ .Ｎｏｗ ,ｔｈｒｅｅｔｙｐｅｓｏｆｅｌｅｃｔｒｏｌｙｔｉｃｃｅｌｌｓａｒｅｕｓｅｄｔｏｐｒｏｄｕｃｅｃｈｌｏｒｉｎｅｇａｓａｎｄｃａｕｓｔｉｃｓｏｄａ:ｔｈｅＨｇｃｅｌｌ,ｔｈｅｄｉａｐｈｒａｇｍｃｅｌｌ,ａｎｄｔｈｅｍｅｍｂｒａｎｅｃｅｌｌ.Ｃｈｉｎａｉｓｕｓｉｎｇｔｈｅｄｉａｐｈｒａｇｍｃｅｌｌａｓｔｈｅｍａｉｎｔｙｐｅ.Ｎａ…     

Foresty offsets in emissions trading systems: a link between systems?

An important aspect in the linking of different emissions trading schemes is the degree to which these systems allow (or ban) external offset project categories. The EU Emission Trading Scheme (EU ETS) currently allows the use of credits from energy and industry projects developed under the Kyoto Protocol’s Joint Implementation (JI) and Clean Development Mechanism (CDM) but excludes the use of carbon credits from forestry projects for compliance in the EU ETS. Forestry credits generated by the CDM have a limited lifetime and expire at the end of a project’s crediting period, or earlier if the carbon stock for which the credits have been issued ceases to exist. According to the recently adopted amendment of the EU ETS Directive forestry credits will remain to be excluded until 2020. The present article reviews how the New South Wales Greenhouse Gas Abatement Scheme (Australia), the Regional Greenhouse Gas Initiative (US) and the voluntary scheme of the Chicago Climate Exchange integrate forestry offsets into the respective system and how they deal with the risk of losing stored and credited biomass. By comparing the results of different scenarios this article shows how differences in the treatment of forestry offsets could impact the efforts to link various emission trading systems in future.

N_2O emissions from forest and grassland soils in northern China

Ｎ２ＯｅｍｉｓｉｏｎｓｆｒｏｍｆｏｒｅｓｔａｎｄｇｒａｓｌａｎｄｓｏｉｌｓｉｎｎｏｒｔｈｅｒｎＣｈｉｎａＬｉｕＹｅ，ＭｕＹｕｊｉｎｇ，ＹａｎｇＷｅｎｘｉａｎｇＲｅｓｅａｒｃｈＣｅｎｔｅｒｆｏｒＥｃｏＥｎｖｉｒｏｎｍｅｎｔａｌＳｃｉｅｎｃｅｓ，Ｃｈ...     

N20 emissions from forest and grassland soils in northern China

Nitrous oxide(N₂O)is a major trace gas in the atmosphere．It plays an important rote in global warming and zone depleting．In this paper，we set up a install to determine the N₂O emission flux from forest and grassland soil．We observed an interesting phenomenon：in our sampling sites，the soil always acts as a source of N₂O，but sometimes it acts as a sink when the temperature is lower than 15℃．     

Decomposition and decoupling analysis of carbon dioxide emissions in African countries during 1984‒2014

The potential for mitigating climate change is growing worldwide, with an increasing emphasis on reducing CO₂ emissions and minimising the impact on the environment. African continent is faced with the unique challenge of climate change whilst coping with extreme poverty, explosive population growth and economic difficulties. CO₂ emission patterns in Africa are analysed in this study to understand primary CO₂ sources and underlying driving forces further. Data are examined using gravity model, logarithmic mean divisia index and Tapio's decoupling indicator of CO₂ emissions from economic development in 20 selected African countries during 1984?2014. Results reveal that CO₂ emissions increased by 2.11% (453.73 million ton) over the research period. Gravity centre for African CO₂ emissions had shifted towards the northeast direction. Population and economic growth were primary driving forces of CO₂ emissions. Industrial structure and emission efficiency effects partially offset the growth of CO₂ emissions. The economic growth effect was an offset factor in central African countries and Zimbabwe due to political instability and economic mismanagement. Industrial structure and emission efficiency were insufficient to decouple economic development from CO₂ emissions and relieve the pressure of population explosion on CO₂ emissions in Africa. Thus, future efforts in reducing CO₂ emissions should focus on scale-up energy-efficient technologies, renewable energy update, emission pricing and long-term green development towards sustainable development goals by 2030.     

Some comments on biological methylation ,global emissions and trade and on residence time in atmosphere of mercury

1　Ｆｏｒｍａｔｉｏｎａｎｄｂｒｅａｋ ｄｏｗｎｏｆｍｅｔｈｙｌｍｅｒｃｕｒｙｉｎｔｅｍｐｅｒａｔｅａｎｄｔｒｏｐｉｃａｌｅｃｏｓｙｓｔｅｍｓ　　Ｓｉｎｃｅｂｉｏｌｏｇｉｃａｌｍｅｔｈｙｌａｔｉｏｎｏｆｍｅｒｃｕｒｙｗａｓｆｉｒｓｔｄｅｓｃｒｉｂｅｄｉｎ 1967(Ｊｅｎｓｅｎ ,1969) ,ｓｅｖｅｒａｌｔｈｏｕｓａｎｄｐａｐｅｒｓｈａｖｅｂｅｅｎｐｕｂｌｉｓｈｅｄｏｎｔｈｅｓｕｂｊｅｃｔ.ＴｈｅｉｎｉｔｉａｌｓｔｕｄｉｅｓｗｅｒｅｄｏｎｅｉｎｆｒｅｓｈｗａｔｅｒｓｅｄｉｍｅｎｔｓｉｎＳｗｅｄｅｎｗｉｔｈｈｉ…     

Wheat straw return can lead to biogenic toluene emissions

As a common practice in agricultural system, straw return has been reported to release a large number of trace gases and attracted much attention. However, the role of straw return in toluene emission remains poorly understood. In this study we measured the emissions of toluene as well as other 50 volatile organic compounds (VOCs) from wheat straw return for 66 days under flooded and non-flooded conditions, respectively. The results showed that substantial toluene was released from the returned ...     

Dovehicular emissions dominate the source of C6-C8aromatics in the megacity Shanghai of eastern China?

The characteristic ratios of volatile organic compounds (VOCs) to i-pentane, the indicator of vehicular emissions, were employed to apportion the vehicular and non-vehicular contributions to reactive species in urban Shanghai. Two kinds of tunnel experiments, one tunnelwith more than 90% light duty gasoline vehicles and the otherwithmore than 60% light duty diesel vehicles, were carried out to study the characteristic ratios of vehicle-related emissions from December 2009 to January 2010. Based on the experiments, the characteristic ratios of C6-C8 aromatics to i-pentane of vehicular emissions were 0.53 ± 0.08 (benzene), 0.70 ± 0.12 (toluene), 0.41 ± 0.09 (m,p-xylenes), 0.16 ± 0.04 (o-xylene), 0.023 ± 0.011 (styrene), and 0.15 ± 0.02 (ethylbenzene), respectively. The source apportionment results showed that around 23.3% of C6-C8 aromatics in urban Shanghai were from vehicular emissions, which meant that the non-vehicular emissions had more importance. These findings suggested that emission control of non-vehicular sources, i.e. industrial emissions, should also receive attention in addition to the control of vehicle-related emissions in Shanghai. The chemical removal of VOCs during the transport from emissions to the receptor site had a large impact on the apportionment results. Generally, the overestimation of vehicular contributions would occur when the VOC reaction rate constant with OH radicals (k_OH) was larger than that of the vehicular indicator, while for species with smaller kOH than the vehicular indicator, the vehicular contribution would be underestimated by the method of characteristic ratios.     

Reducing emissions from deforestation and forest degradation plus (REDD+) in the Philippines: will it make a difference in financing forest development?

There is a high level of interest in reducing emissions from deforestation and forest degradation plus (REDD+) carbon (C) financing as a way to accelerate forest conservation and development. However, there is very limited information on the potential costs and benefits of REDD+ in developing countries like the Philippines. In this paper, we estimated the range of likely financial benefits of REDD+ implementation in the country under various forest degradation and mitigation scenarios. Our findings show that reducing the rate of forest degradation by a modest 5 to 15 % annually while increasing the doubling the rate of reforestation to 1.5 % annually could reduce C emissions by up to about 60 million t C by 2030. These are equivalent to US$ 97 to 417 million of mean C credits annually at US$ 5 per ton C. These figures are much higher than the total budget of the government and official development assistance for forestry activities in the country which amounted to US$ 46 million in 2005 and US$ 12 million in 2006, respectively. We conclude that REDD+ C credits could be a significant source of financing for forestry projects in developing countries like the Philippines.     

Air pollution characteristics and their relationship with emissions and meteorology in the Yangtze River Delta region during 2014–2016

With rapid economic growth and urbanization, the Yangtze River Delta(YRD) region in China has experienced serious air pollution challenges. In this study, we analyzed the air pollution characteristics and their relationship with emissions and meteorology in the YRD region during 2014–2016. In recent years, the concentrations of all air pollutants, except O_3,decreased. Spatially, the PM_(2.5), PM_(10), SO_2, and CO concentrations were higher in the northern YRD region, and NO_2 and O_3 were higher in the central YRD region. Based on the number of non-attainment days(i.e., days with air quality index greater than 100), PM_(2.5) was the largest contributor to air pollution in the YRD region, followed by O_3, PM_(10), and NO_2.However, particulate matter pollution has declined gradually, while O_3 pollution worsened.Meteorological conditions mainly influenced day-to-day variations in pollutant concentrations. PM_(2.5) concentration was inversely related to wind speed, while O_3 concentration was positively correlated with temperature and negatively correlated with relative humidity.The air quality improvement in recent years was mainly attributed to emission reductions.During 2014–2016, PM_(2.5), PM_(10), SO_2, NO_x, CO, NH_3, and volatile organic compound(VOC)emissions in the YRD region were reduced by 26.3%, 29.2%, 32.4%, 8.1%, 15.9%, 4.5%, and0.3%, respectively. Regional transport also contributed to the air pollution. During regional haze periods, pollutants from North China and East China aggravated the pollution in the YRD region. Our findings suggest that emission reduction and regional joint prevention and control helped to improve the air quality in the YRD region.     

The relationship between upwind SO2 emissions and SO4– concentrations in precipitation at six sites in the eastern U.S.A.

A method for estimating the upwind SO₂ emissions associated with individual wet SO₄²⁻ deposition events has been developed. The relationship between these estimates and wet SO₄²⁻ concentrations was examined at six Utility Acid Precipitation Study Program Sites (UAPSP) for the 1979–1986 period. Using Spearman correlation coefficients and the Bonferroni experimentwise criterion for statistical significance it was found that upwind emissions and concentrations were significantly related (p < 0.05). However, correlation's were sensitive to site location, time upwind of the emissions and season, and ranged from −0.03 to 0.50. Correlations were weaker at sites located west of the high emission region in the midwestern U.S.A. and stronger at sites further away and to the east of this region. There was a decrease in the strength of the correlations from the warm season to the cold season. It was also found that differences in meteorology between events obscured the relationship between emissions and concentrations. The effects of variations in ambient temperature and precipitation amount on wet SO₄²⁻ concentrations were taken into account by calculating partial correlation coefficients. A higher percentage of the resulting correlations were found to be statistically significant and the differences between sites decreased. This suggested that meteorological variability had a confounding influence on the detection of a link between concentrations and emissions. This influence should be considered when studying source-receptor relationships.     

Olfaction in a viscous environment: the “color” of sexual smells in <Emphasis Type="Italic">Temora longicornis</Emphasis>

We investigate chemical aspects of mating in the marine copepod Temora longicornis (Copepoda, Calanoidea). Our emphasis is the female pheromone signaling in form of well-defined trails for males to follow, observed in Doall et al. (Phil Trans R Soc Lond B 353:681–689, 1998). The viscous environment and the properties of the odorants play important roles as the spread of the pheromone trail limits the time during which it is useful for tracing. A key observation from our earlier work is the ability of a searching male to detect the direction of the female and to correct its swimming direction if necessary. We propose a simple mathematical model for the spread of a pheromone from a moving source and carry out numerical simulations of two possible detection mechanisms. We find that a searching agent that is capable to detect a ratio outperforms a searcher that depends on the gradient of a single compound. This suggests that copepod sex pheromones consist of blends of chemical compounds, and that a ratio detection mechanism similar to that in airborne insects is at work.     

Do vehicular emissions dominate the source of C6–C8 aromatics in the megacity Shanghai of eastern China?

The characteristic ratios of volatile organic compounds(VOCs) to i-pentane, the indicator of vehicular emissions, were employed to apportion the vehicular and non-vehicular contributions to reactive species in urban Shanghai. Two kinds of tunnel experiments, one tunnel with more than 90% light duty gasoline vehicles and the other with more than 60% light duty diesel vehicles, were carried out to study the characteristic ratios of vehicle-related emissions from December 2009 to January 2010. Based on the experiments, the characteristic ratios of C6–C8aromatics to i-pentane of vehicular emissions were 0.53 ± 0.08(benzene), 0.70 ± 0.12(toluene),0.41 ± 0.09(m,p-xylenes), 0.16 ± 0.04(o-xylene), 0.023 ± 0.011(styrene), and 0.15 ± 0.02(ethylbenzene), respectively. The source apportionment results showed that around 23.3% of C6–C8 aromatics in urban Shanghai were from vehicular emissions, which meant that the non-vehicular emissions had more importance. These findings suggested that emission control of non-vehicular sources, i.e. industrial emissions, should also receive attention in addition to the control of vehicle-related emissions in Shanghai. The chemical removal of VOCs during the transport from emissions to the receptor site had a large impact on the apportionment results. Generally, the overestimation of vehicular contributions would occur when the VOC reaction rate constant with OH radicals(k OH) was larger than that of the vehicular indicator, while for species with smaller k OH than the vehicular indicator, the vehicular contribution would be underestimated by the method of characteristic ratios.     

Brain modulation of Dufour’s gland ester biosynthesis in vitro in the honeybee (<Emphasis Type="Italic">Apis mellifera</Emphasis>)

Caste-specific pheromone biosynthesis is a prerequisite for reproductive skew in the honeybee. Nonetheless, this process is not hardwired but plastic, in that egg-laying workers produce a queen-like pheromone. Studies with Dufour’s gland pheromone revealed that, in vivo, workers’ gland biosynthesis matches the social status of the worker, i.e., sterile workers showed a worker-like pattern whereas fertile workers showed a queen-like pattern (production of the queen-specific esters). However, when incubated in vitro, the gland spontaneously exhibits the queen-like pattern, irrespective of its original worker type, prompting the notion that ester production in workers is under inhibitory control that is queen-dependent. We tested this hypothesis by exposing queen or worker Dufour’s glands in vitro to brain extracts of queens, queenright (sterile) workers and males. Unexpectedly, worker brain extracts activated the queen-like esters biosynthesis in workers’ Dufour’s gland. This stimulation was gender-specific; queen or worker brains demonstrated a stimulatory activity, but male brains did not. Queen gland could not be further stimulated. Bioassays with heated and filtered extracts indicate that the stimulatory brain factor is below 3,000 Da. We suggest that pheromone production in Dufour’s gland is under dual, negative–positive control. Under queenright conditions, the inhibitor is released and blocks ester biosynthesis, whereas under queenless conditions, the activator is released, activating ester biosynthesis in the gland. This is consistent with the hypothesis that queenright workers are unequivocally recognized as non-fertile, whereas queenless workers try to become “false queens” as part of the reproductive competition.     

Within-population variation in ejaculate characteristics in a prolonged breeder,Peron’s tree frog, <Emphasis Type="Italic">Litoria peronii</Emphasis>

Sperm number is often a good predictor of success in sperm competition; however, it has become increasingly clear that, for some species, variation in probability of paternity cannot be explained by sperm number alone. Intraspecific variation in ejaculate characteristics, such as the number of viable sperm and sperm longevity, may play an equally important role in determining fertilization success. Here, we assess variation among ejaculates in three factors that may contribute to fertilization success (number of sperm per ejaculate, viability, and longevity), in a population of Peron’s tree frog (Litoria peronii). We detected large variation among males in the number of sperm per ejaculate and the proportion of viable sperm within ejaculates, which could not be explained by variation in either male size or body condition. However, the proportion of viable sperm released by males increased over the season. Finally, we assessed sperm longevity (proportion viable sperm determined using a dual-fluorochrome vital dye) at two different temperatures. At 23°C, on average, 75% of sperm remained viable after 2 h, but there were significant differences amongst males with the percentage of viable sperm ranging from 43% to 95%. For sperm incubated at 4°C, ejaculates varied fivefold in sperm longevity with some males having 50% viable sperm after 5 days. Our data suggest that ejaculate characteristics (sperm number, viability, and longevity) vary widely in Peron’s tree frog and may therefore play an important role in determining siring success both in the presence and absence of sperm competition. We discuss the results in relation to selection on ejaculate traits via natural and sexual selection in this and other amphibians.