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The study investigates the nexus of CO2 emissions, tourism, fossil fuels, and GDP growth using China’s data from 1970 to 2019. The research applied the upset U-molded EKC and the ARDL -models to calculate the time series stationarity variables. The results showed that in the initial enlargement phases, a sophisticated GDP adversely impacts CO2 emissions, then a higher GDP positively influences CO2 emissions. The development of tourism, use of fossil fuels (coal and oil), and population growth show an important influence on CO2 emissions but the use of gas and electricity has little effect on CO2 emissions. In contrast, foreign direct investment besides population development had little effect on increasing CO2 emissions. Retreating foreign direct investment, strengthening the use of sustainable electricity, and improving transportation for explorers, especially the green tourism business, are excellent ways to reduce environmental degradation in China.

Half the population of China live in coastal zones where 70% of large cities are also located. Intensive human activities pose significant environmental and ecological hazards to these cities that are already vulnerable to natural hazards and climate change. The sustainable development of coastal cities is thus both a national and international issue. Rongcheng is a typical coastal city in east China. It is a national marine ranch demonstration area that is subjected to multi-stressors from human activities and climate change. The dominant economic sectors include aquaculture and fisheries, agriculture, shipping and tourism. A multitude of resulting pressures come mainly from intensified human activities, such as intensive aquaculture, overfishing, industrial pollutants, agricultural runoff, land reclamation and port expansion. In addition, Rongcheng is also facing exogenic pressures from extreme climate events such as intensified storms, storm surges, droughts and sea ice. A growing awareness of these problems brought together a trans-disciplinary group from local government, research institutions, local practitioners and coastal representatives to jointly explore and co-design adaptive coastal management options. In this transdisciplinary study, a social-ecological analysis based on a combination of the Systems Approach Framework and the Drivers-Pressures-States-Impacts-Responses framework was used to analyze and formulate an adaptive management plan for the sustainability of Rongcheng. More than 40 stakeholders including government, companies, civil society and institutions participated in the study through questionnaires and on-site meetings. A statistical analysis of the results identified urgent issues impeding the sustainable development of Rongcheng. The issues identified were poorly regulated aquaculture, loss of shoreline, and the decline of seagrass and cultural heritage. The study identified management options and measures, some of which were adopted by the local government in a co-designed management plan. The measures included upgrading of aquaculture industry, habitat conservation and restoration, and the development of cultural tourism. Another outcome was the increased knowledge exchange between stakeholders to inform management, policy, and decision making, as well as raised awareness of vulnerability to natural hazards and climate change. The success of this case study provides a reference for the adaptive management of other coastal cities and their sustainable development in a changing climate.

Low-carbon technological progress is an important way to achieve energy conservation and emission reduction, as well as achieve the goal of peaking carbon emission and carbon neutrality. Due to the difference in energy input structure, the difficulty of attaining low-carbon technology progress in industries with different energy consumption levels will lead to different responses to environmental regulation, affecting energy efficiency. This paper demonstrates the theoretical mechanism of how environmental regulation affects energy-saving efficiency through low-carbon technological progress in industries with different energy consumption levels. By reconstructing energy consumption of different industries in each province, this paper estimates the low-carbon technology progress in high-energy-consuming industries and low-energy-consuming industries in 30 provinces and cities of China from 2000 to 2016. It carries out empirical tests using mediating effect model. The results show that nationwide, the impact of environmental regulation on energy efficiency through low-carbon technology progress is U-shaped. Low-carbon technology progress accelerates the inflection point, indicating that the progress of low-carbon technology is beneficial for strict environmental regulation policies to improve energy efficiency. It shows there is asymmetric regional heterogeneity in the impact of environmental regulation on energy efficiency through low-carbon technology progress in high-energy-consuming and low-energy-consuming industries: in the central-western region, the progress of low-carbon technology in high-energy-consuming industries is faster than that in low-energy-consuming industries; in eastern region, room for energy-saving through low-carbon technology in low-energy-consuming industries is more significant than that in high-energy-consuming industries. This paper provides empirical evidence and policy suggestions for China to implement differentiated environmental regulation policies in accordance with local conditions, promote green technology transformation, and conserve the ecological civilization.

Rivers are significant sources of greenhouse gases (GHGs; e.g., CH4 and CO2); however, our understanding of the large-scale longitudinal patterns of GHG emissions from rivers remains incomplete, representing a major challenge in upscaling. Local hotspots and moderate heterogeneities may be overlooked by conventional sampling schemes. In August 2020 and for the first time, we performed continuous (once per minute) CH4 measurements of surface water during a 584-km-long river cruise along the German Elbe to explore heterogeneities in CH4 concentration at different spatial scales and identify CH4 hotspots along the river. The median concentration of dissolved CH4 in the Elbe was 112 nmol L−1, ranging from 40 to 1,456 nmol L−1 The highest CH4 concentrations were recorded at known potential hotspots, such as weirs and harbors. These hotspots were also notable in terms of atmospheric CH4 concentrations, indicating that measurements in the atmosphere above the water are useful for hotspot detection. The median atmospheric CH4 concentration was 2,033 ppb, ranging from 1,821 to 2,796 ppb. We observed only moderate changes and fluctuations in values along the river. Tributaries did not obviously affect CH4 concentrations in the main river. The median CH4 emission was 251 μmol m−2 d−1, resulting in a total of 28,640 mol d−1 from the entire German Elbe. Similar numbers were obtained using a conventional sampling approach, indicating that continuous measurements are not essential for a large-scale budget. However, we observed considerable lateral heterogeneity, with significantly higher concentrations near the shore only in reaches with groins. Sedimentation and organic matter mineralization in groin fields evidently increase CH4 concentrations in the river, leading to considerable lateral heterogeneity. Thus, river morphology and structures determine the variability of dissolved CH4 in large rivers, resulting in smooth concentrations at the beginning of the Elbe versus a strong variability in its lower parts. In conclusion, groin construction is an additional anthropogenic modification following dam building that can significantly increase GHG emissions from rivers.

Adaptation to climate change has gained a prominent place next to mitigation on global, national, and local policy agendas. However, while an abundance of adaptation strategies, plans, and programmes have been developed, progress in turning these into action has been slow. The development of a sound knowledge basis to support adaptation globally is suggested to accelerate progress, but has lagged behind. The emphasis in both current and newly proposed programmes is very much on practice-oriented research with strong stakeholder participation. This paper supports such practice-oriented research, but argues that this is insufficient to support adaptation policy and practice in a productive manner. We argue that there is not only a need for science for adaptation, but also a science of adaptation. The paper argues that participatory, practice-oriented research is indeed essential, but has to be complemented by and connected to more fundamental inquiry and concept development, which takes into account knowledge that has been developed in disciplinary sciences and on issues other than climate change adaptation. At the same time, the level and method of participation in science for adaptation should be determined on the basis of the specific project context and goals. More emphasis on science of adaptation can lead to improved understanding of the conditions for successful science for adaptation.

To meet the carbon neutrality target and Beautiful China goal, the co-control strategy of carbon emission and air pollution is crucial. The Beijing-Tianjin-Hebei region is a prominent cooperative development zone, which faces dual challenges of CO2 emission reduction and air pollution control. This study aims to find the co-benefit pathway for achieving both targets in Beijing-Tianjin-Hebei. Based on an innovative and integrated framework by linking the computable general equilibrium model, atmospheric environment analysis model and health impact assessment model, we analyze the mutual co-benefits of carbon reduction and air quality improvement by climate and environmental policies. The results show significant mutual effects of CO2 emission mitigation and air pollution reduction. From the regional view, air pollutants control and CO2 mitigation policies have a relatively higher synergistic emission reduction effect in Beijing and Tianjin than in Hebei. From the sector perspective, the energy supply and transport sectors have much higher co-effects with CO2 reduction, while climate change mitigation policies have the best co-effects with air pollution reduction in the energy supply and residential sectors. Moreover, the health benefits in the air pollution control scenario (6.0 BUSD) are higher than in the decarbonization scenario (5.7 BUSD). In addition, climate mitigation policies could have tremendous synergistic air pollution reductions, even the health benefits (5.7 BUSD) may be insufficient to offset the cost (18.7 BUSD) of climate policy in the current situation. In order to better achieve the dual climate and air quality targets at lower costs, two types of policies should be better coordinated in the decision-making process.

In a changing world, phytoplankton communities face a large variety of challenges including altered light regimes. These alterations are caused by more pronounced stratification due to rising temperatures, enhanced eutrophication, and browning of lakes. Community responses toward these effects can emerge as alterations in physiology, biomass, biochemical composition, or diversity. In this study, we addressed the combined effects of changes in light and nutrient conditions on community responses. In particular, we investigated how light intensity and variability under two nutrient conditions influence (1) fast responses such as adjustments in photosynthesis, (2) intermediate responses such as pigment adaptation and (3) slow responses such as changes in community biomass and species composition. Therefore, we exposed communities consisting of five phytoplankton species belonging to different taxonomic groups to two constant and two variable light intensity treatments combined with two levels of phosphorus supply. The tested phytoplankton communities exhibited increased fast reactions of photosynthetic processes to light variability and light intensity. The adjustment of their light harvesting mechanisms via community pigment composition was not affected by light intensity, variability, or nutrient supply. However, pigment specific effects of light intensity, light variability, and nutrient supply on the proportion of the respective pigments were detected. Biomass was positively affected by higher light intensity and nutrient concentrations while the direction of the effect of variability was modulated by light intensity. Light variability had a negative impact on biomass at low, but a positive impact at high light intensity. The effects on community composition were species specific. Generally, the proportion of green algae was higher under high light intensity, whereas the cyanobacterium performed better under low light conditions. In addition to that, the diatom and the cryptophyte performed better with high nutrient supply while the green algae as well as the cyanobacterium performed better at low nutrient conditions. This shows that light intensity, light variability, and nutrient supply interactively affect communities. Furthermore, the responses are highly species and pigment specific, thus to clarify the effects of climate change a deeper understanding of the effects of light variability and species interactions within communities is important.

Le riz est une culture vivrière importante au Kenya et il est classé troisième culture céréalière la plus consommée après le maïs et le blé. La demande amplifiée de riz a entraîné la conversion des zones humides en rizières et l'utilisation accrue d'engrais, réduisant ainsi la capacité des zones humides à séquestrer le carbone. Par conséquent, il y a une augmentation des émissions de trois gaz à effet de serre (GES) puissants : le méthane (CH4), l'oxyde nitreux (N2O) et le dioxyde de carbone (CO2). Cette étude a évalué l'impact de l'application d'engrais sur les émissions de GES et les stocks de nutriments dans les rizières. L'étude a été réalisée de septembre 2018 à janvier 2019 dans des zones humides dominées par les papyrus dans l'ouest du Kenya. L'échantillonnage a été effectué sur une base hebdomadaire pendant les deux premiers mois, puis deux fois par mois dans les rizières Anyiko situées dans le bassin de la rivière Nzoia, au Kenya. Deux répliques de trois traitements ; standard, témoin et sous fertilisation ont été attribuées au hasard dans six parcelles. La méthode de la chambre statique a été utilisée pour collecter les GES et analysée par chromatographie en phase gazeuse. Des échantillons de sol ont été collectés et analysés pour les stocks d'azote et de carbone. Il n'y avait pas de différence significative dans les stocks de carbone et d'azote entre les trois scénarios de fertilisation (ANOVA unidirectionnelle, F (2,33)=0,219, P>0,05 pour le carbone et F(2,33)=0,134, P>0,05 pour l'azote). La quantité de NO3-N et de NH4-N n'était pas significativement différente dans tous les scénarios de fertilisation (Kruskal-Wallis, P>0,05). Le test de Kruskal-Wallis (P>0,05) a indiqué qu'il n'y avait pas de différence significative dans les flux moyens de CH4 et de CO2 entre les trois scénarios de fertilisation. Cependant, pour le N2O, les flux moyens diffèrent significativement (P<0,05). Les flux moyens ont indiqué que la parcelle sous-fertilisée était un puits probable de N2O (- 0,59±0,45 µgm- ²h-¹) et une source de CH4 (6,93±2,42 mgm-²h-¹) et de CO2 (208,81±36,20 mgm-²h-¹). La parcelle fertilisée standard était source de N2O, CO2 et CH4 (4,37±3,18µgm- ²h-¹,248,29 ±41,22mgm- ²h-¹, 4,00±6,34 mgm-²h-¹, respectivement). La parcelle témoin a servi de puits pour le N2O (-3,59±2,56 µgm- ²h-¹) et de source pour le CH4 (8,30±4,79 mgm-²h-¹) et le CO2 (174,80±26,81 mgm-²h-¹). Dans cette étude, différents scénarios de fertilisation ont eu un effet positif sur les émissions de N2O mais aucun effet sur les émissions de CO2 et de CH4 ainsi que sur les stocks de nutriments. El arroz es un cultivo alimentario importante en Kenia y ocupa el tercer lugar entre los cultivos de cereales más consumidos después del maíz y el trigo. La mayor demanda de arroz ha dado como resultado la conversión de humedales en arrozales y un mayor uso de fertilizantes, lo que reduce la capacidad de los humedales para secuestrar carbono. En consecuencia, hay una mayor emisión de tres potentes gases de efecto invernadero (GEI): metano (CH4), óxido nitroso (N2O) y dióxido de carbono (CO2). Este estudio evaluó el impacto de la aplicación de fertilizantes en las emisiones de GEI y las reservas de nutrientes en los arrozales. El estudio se llevó a cabo desde septiembre de 2018 hasta enero de 2019 en un humedal dominado por papiros en el oeste de Kenia. El muestreo se realizó semanalmente durante los primeros dos meses, y posteriormente dos veces al mes en los arrozales Anyiko ubicados en la cuenca del río Nzoia, Kenia. Dos réplicas de tres tratamientos; estándar, control y subfertilización se asignaron aleatoriamente en seis parcelas. Se utilizó el método de cámara estática para recoger los GEI y se analizó mediante cromatografía de gases. Se recogieron muestras de suelo y se analizaron las reservas de nitrógeno y carbono. No hubo diferencias significativas en las reservas de carbono y nitrógeno entre los tres escenarios de fertilización (ANOVA unidireccional, F (2,33)=0,219, P>0,05 para el carbono y F(2,33)=0,134, P>0,05 para el nitrógeno). La cantidad de NO3-N y NH4-N no fue significativamente diferente en todos los escenarios de fertilización (Kruskal-Wallis, P>0.05). La prueba de Kruskal-Wallis (P>0.05) indicó que no hubo diferencias significativas en los flujos medios de CH4 y CO2 entre los tres escenarios de fertilización. Sin embargo, para N2O los flujos medios difirieron significativamente (P<0.05). Los flujos medios indicaron que la parcela poco fertilizada era un probable sumidero para N2O (- 0.59±0.45µgm- ²h-¹) y una fuente para CH4 (6.93±2.42 mgm- ²h-¹) y CO2 (208.81±36.20 mgm-²h-¹). La gráfica fertilizada estándar fue la fuente de N2O, CO2 y CH4 (4.37±3.18 µgm- ²h-¹,248.29 ±41.22mgm- ²h-¹, 4.00±6.34mgm- ²h-¹,) respectivamente. La parcela de control actuó como sumidero para N2O (-3.59±2.56µgm- ²h-¹) y una fuente para CH4 (8.30±4.79 mgm-²h-¹) y CO2 (174.80±26.81 mgm-²h-¹). En este estudio, diferentes escenarios de fertilización tuvieron un efecto positivo sobre la emisión de N2O pero ningún efecto sobre la emisión de CO2 y CH4 y también sobre las reservas de nutrientes. Rice is an important food crop in Kenya and it is ranked third most consumed cereal crop after maize and wheat. The amplified demand for rice has resulted to conversion of wetlands to rice paddies and increased use of fertilizer, thus reducing wetlands ability to carbon sequestration. Consequently, there is enhanced emission of three potent greenhouse gases (GHGs); methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2). This study assessed the impact of fertilizer application on GHGs emission and the nutrient stocks in rice paddies. The study was carried out from September 2018 to January 2019 in papyrus dominated wetland in Western Kenya. Sampling was done on a weekly basis for the first two months, and thereafter twice per month in Anyiko rice paddies located in river Nzoia basin, Kenya. Two replicates of three treatments; standard, control and under fertilization were assigned randomly in six plots. Static chamber method was used to collect GHGs and analysed by gas chromatography. Soil samples were collected and analysed for nitrogen and carbon stocks. There was no significant difference in carbon and nitrogen stocks among the three fertilization scenarios (One-way ANOVA, F (2,33)=0.219, P>0.05 for carbon and F(2,33)=0.134, P>0.05 for nitrogen). The amount of NO3-N and NH4-N were not significantly different across all the fertilization scenarios (Kruskal-Wallis, P>0.05). Kruskal-Wallis test (P>0.05) indicated that there was no significant difference in the mean fluxes of CH4 and CO2 among the three fertilization scenarios. However, for N2O the mean fluxes differed significantly (P<0.05). The mean fluxes indicated that under-fertilized plot was a probable sink for N2O (- 0.59±0.45 µgm-²h-¹) and a source for CH4 (6.93±2.42 mgm-²h-¹) and CO2 (208.81±36.20 mgm-²h-¹). Standard-fertilized plot was source for N2O, CO2 and CH4 (4.37±3.18 µgm-²h-¹, 248.29±41.22 mgm-²h-¹, 4.00±6.34 mgm-²h-¹,) respectively. The control plot acted as sink for N2O (-3.59±2.56 µgm-²h-¹) and a source for CH4 (8.30±4.79 mgm-²h-¹) and CO2 (174.80±26.81 mgm-²h-¹). In this study, different fertilization scenarios had positive effect on N2O emission but no effect on CO2 and CH4 emission and also on nutrient stocks. يعتبر الأرز محصولًا غذائيًا مهمًا في كينيا ويحتل المرتبة الثالثة في محصول الحبوب الأكثر استهلاكًا بعد الذرة والقمح. وقد أدى الطلب المتزايد على الأرز إلى تحويل الأراضي الرطبة إلى حقول للأرز وزيادة استخدام الأسمدة، مما يقلل من قدرة الأراضي الرطبة على عزل الكربون. وبالتالي، هناك انبعاثات معززة لثلاثة غازات دفيئة قوية (GHGs) ؛ الميثان (CH4) وأكسيد النيتروز (N2O) وثاني أكسيد الكربون (CO2). قيمت هذه الدراسة تأثير استخدام الأسمدة على انبعاثات غازات الدفيئة ومخزونات المغذيات في حقول الأرز. أجريت الدراسة في الفترة من سبتمبر 2018 إلى يناير 2019 في الأراضي الرطبة التي تهيمن عليها البردي في غرب كينيا. تم أخذ العينات على أساس أسبوعي خلال الشهرين الأولين، وبعد ذلك مرتين في الشهر في حقول أرز أنييكو الواقعة في حوض نهر نزويا في كينيا. تم تعيين نسختين متماثلتين من ثلاثة علاجات ؛ قياسية ومراقبة وتحت الإخصاب بشكل عشوائي في ست قطع. تم استخدام طريقة الغرفة الساكنة لجمع غازات الدفيئة وتحليلها بواسطة كروماتوغرافيا الغاز. تم جمع عينات التربة وتحليلها لمخزونات النيتروجين والكربون. لم يكن هناك فرق كبير في مخزونات الكربون والنيتروجين بين سيناريوهات التسميد الثلاثة (أحادي الاتجاه ANOVA، F (2,33)=0.219، P>0.05 للكربون و F(2,33)=0.134، P>0.05 للنيتروجين). لم تكن كمية NO3 - N و NH4 - N مختلفة بشكل كبير عبر جميع سيناريوهات الإخصاب (Kruskal - Wallis، P>0.05). أشار اختبار كروسكال واليس (P>0.05) إلى عدم وجود فرق كبير في متوسط تدفقات الميثان وثاني أكسيد الكربون بين سيناريوهات التسميد الثلاثة. ومع ذلك، بالنسبة لأكسيد النيتروز، اختلف متوسط التدفقات بشكل كبير (P<0.05). أشار متوسط التدفقات إلى أن قطعة الأرض غير المخصبة كانت بالوعة محتملة لأكسيد النيتروز (- 0.59±0.45 ميكروغرام- ²ح-¹) ومصدرًا للميثان (6.93±2.42 مجم- ²ح-¹) وثاني أكسيد الكربون (208.81±36.20 مجم- ²ح-¹). كان المخطط المخصب القياسي مصدرًا لأكسيد النيتروز وثاني أكسيد الكربون والميثان (4.37±3.18 ميكروغرام-²ساعة-¹، 248.29±41.22 مجم-²ساعة-¹، 4.00±6.34 مجم- ²ساعة-¹، على التوالي). كانت قطعة التحكم بمثابة حوض لأكسيد النيتروز (-3.59 ±2.56 ميكروغرام - ²h -¹) ومصدر للميثان (8.30±4.79 مجم - ²h -¹) وثاني أكسيد الكربون (174.80±26.81 مجم - ²h -¹). في هذه الدراسة، كان لسيناريوهات التسميد المختلفة تأثير إيجابي على انبعاثات أكسيد النيتروز ولكن لم يكن لها أي تأثير على انبعاثات ثاني أكسيد الكربون والميثان وكذلك على مخزونات المغذيات.