The impact of CO2 emission scenarios and nutrient enrichment on a common coral reef macroalga is modified by temporal effects

2014 ◽  
Vol 50 (1) ◽  
pp. 203-215 ◽  
Author(s):  
Dorothea Bender ◽  
Guillermo Diaz-Pulido ◽  
Sophie Dove
Author(s):  
Qiong Wu ◽  
Kanittha Tambunlertchai ◽  
Pongsa Pornchaiwiseskul

The global warming has become a serious issue in the world since the 1980s. The targets for the first commitment period of the Kyoto Protocol cover emissions of the six main greenhouse gasses (GHGs). China is the world's largest CO2 emitter and coal consumer and was responsible for 27.3 percent of the global total CO2 emission and 50.6 percent of the global total coal consumption in 2016 (BP, 2017). As China plays an important role in the global climate change, China has set goals to improve its environmental efficiency and performance. In 2011, the Chinese government for the first time announced an intent to establish carbon emission trading market in China. Eight regional emission trading schemes have been operating since 2013 (seven pilot markets during the 12th Five Year Plan period and one pilot market during the 13th Five Year Plan period) including provinces of Guangdong, Hubei, and Fujian, and cities of Beijing, Tianjin, Shanghai, Shenzhen, and Chongqing. The goal of these regional emission trading pilot markets is to help the government establish an efficient carbon emission trading scheme at national level. Some researchers have been focused on examining the impact of emission trading schemes in China using CGE model by constructing different scenarios and ex-ante analysis using data prior to emission trading pilot markets implementation. While this paper tries to conduct an ex-post analysis with data of 2005-2017 to evaluate the impact of emission trading pilot markets in China at provincial level using difference-in-difference (DID) model. By including both CO2 and SO2 as undesirable outputs to calculate Malmquist-Luenberger (ML) Index to measure green total factor productivity, this paper plans to evaluate the impact of carbon emission trading pilot markets in China via emission reduction, regional green development, synergy effect and influencing channels. This paper tries to answer the following research questions: (1) Do emission trading pilot markets reduce CO2 emission and increase regional green total factor productivity? (2) Is there any synergy effect from emission trading pilot markets? (3) What are the influencing channels of emission trading pilot markets? Keywords: Emission trading, CO2 emissions, Different-in-difference


Coral Reefs ◽  
2021 ◽  
Author(s):  
Gabriele Gerlach ◽  
Philipp Kraemer ◽  
Peggy Weist ◽  
Laura Eickelmann ◽  
Michael J. Kingsford

AbstractCyclones have one of the greatest effects on the biodiversity of coral reefs and the associated species. But it is unknown how stochastic alterations in habitat structure influence metapopulation structure, connectivity and genetic diversity. From 1993 to 2018, the reefs of the Capricorn Bunker Reef group in the southern part of the Great Barrier Reef were impacted by three tropical cyclones including cyclone Hamish (2009, category 5). This resulted in substantial loss of live habitat-forming coral and coral reef fish communities. Within 6–8 years after cyclones had devastated, live hard corals recovered by 50–60%. We show the relationship between hard coral cover and the abundance of the neon damselfish (Pomacentrus coelestis), the first fish colonizing destroyed reefs. We present the first long-term (2008–2015 years corresponding to 16–24 generations of P. coelestis) population genetic study to understand the impact of cyclones on the meta-population structure, connectivity and genetic diversity of the neon damselfish. After the cyclone, we observed the largest change in the genetic structure at reef populations compared to other years. Simultaneously, allelic richness of genetic microsatellite markers dropped indicating a great loss of genetic diversity, which increased again in subsequent years. Over years, metapopulation dynamics were characterized by high connectivity among fish populations associated with the Capricorn Bunker reefs (2200 km2); however, despite high exchange, genetic patchiness was observed with annual strong genetic divergence between populations among reefs. Some broad similarities in the genetic structure in 2015 could be explained by dispersal from a source reef and the related expansion of local populations. This study has shown that alternating cyclone-driven changes and subsequent recovery phases of coral habitat can greatly influence patterns of reef fish connectivity. The frequency of disturbances determines abundance of fish and genetic diversity within species.


Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 130
Author(s):  
Mihail Busu ◽  
Alexandra Catalina Nedelcu

In the past decades, carbon dioxide (CO2) emissions have become an important issue for many researchers and policy makers. The focus of scientists and experts in the area is mainly on lowering the CO2 emission levels. In this article, panel data is analyzed with an econometric model, to estimate the impact of renewable energy, biofuels, bioenergy efficiency, population, and urbanization level on CO2 emissions in European Union (EU) countries. Our results underline the fact that urbanization level has a negative impact on increasing CO2 emissions, while biofuels, bioenergy production, and renewable energy consumption have positive and direct impacts on reducing CO2 emissions. Moreover, population growth and urbanization level are negatively correlated with CO2 emission levels. The authors’ findings suggest that the public policies at the national level must encourage the consumption of renewable energy and biofuels in the EU, while population and urbanization level should come along with more restrictions on CO2 emissions.


2015 ◽  
Vol 7 (1) ◽  
pp. 39-51 ◽  
Author(s):  
Ali Fares ◽  
Ripendra Awal ◽  
Samira Fares ◽  
Alton B. Johnson ◽  
Hector Valenzuela

The impact of potential future climate change scenarios on the irrigation water requirements (IRRs) of two major agricultural crops (coffee and seed corn) in Hawai'i was studied using the Irrigation Management System (IManSys) model. In addition to IRRs calculations, IManSys calculates runoff, deep percolation, canopy interception, and effective rainfall based on plant growth parameters, site specific soil hydrological properties, irrigation system efficiency, and long-term daily weather data. Irrigation water requirements of two crops were simulated using historical climate data and different levels of atmospheric CO2 (330, 550, 710 and 970 ppm), temperature (+1.1 and +6.4 °C) and precipitation (±5, ±10 and ±20%) chosen based on the Intergovernmental Panel on Climate Change (IPCC) AR4 projections under reference, B1, A1B1 and A1F1 emission scenarios. IRRs decreased as CO2 emission increased. The average percentage decrease in IRRs for seed corn is higher than that of coffee. However, runoff, rain canopy interception, and deep percolation below the root zone increased as precipitation increased. Canopy interception and drainage increased with increased CO2 emission. Evapotranspiration responded positively to air temperature rise, and as a result, IRRs increased as well. Further studies using crop models will predict crop yield responses to these different irrigation scenarios.


2016 ◽  
Author(s):  
Hadi Eskandari Dameneh ◽  
Moslem Borji ◽  
Hassan Khosravi ◽  
Ali Salajeghe

Abstract. Persistence of widespread degradation in arid and semi-arid region of Iran necessitates using of monitoring and evaluation systems with appropriate accuracy to determine the degradation process and adoption of early warning systems; because after transition from some thresholds, effective reversible function of ecosystems will not be very easy. This paper tries to monitor the degradation and desertification trends in three land uses including range, forest and desert lands affected by climate change in Tehran province for 2000s and 2030s. For assessing climate changes of Mehrabad synoptic stations the data of two emission scenarios including A2 and B2 were used using statistical downscaling techniques and data generated by SDSM model. The index of net primary production resulting from MODIS satellite images was employed as an indicator of destruction from 2001 to 2010. The results showed that temperature is the most effective driver force which alters the net primary production in rangeland, forest and desert ecosystems of Tehran province. On the basis of monitoring findings under real conditions, in the 2000s, over 60 % of rangelands and 80 % of the forests have been below the average production in the province. On the other hand, the long-term average changes of NPP in rangeland and forests indicated the presence of relatively large areas of these land uses with production rate lower than the desert. The results also showed that, assuming the existence of circumstances of each emission scenarios, the desertification status will not improve significantly in the rangelands and forests of Tehran province.


2012 ◽  
Vol 12 (8) ◽  
pp. 21211-21239 ◽  
Author(s):  
R. Wang ◽  
S. Tao ◽  
P. Ciais ◽  
H. Z. Shen ◽  
Y. Huang ◽  
...  

Abstract. High-resolution mapping of fuel combustion and CO2 emission provides valuable information for inferring terrestrial carbon balance, modeling pollutant transport, and developing mitigation strategies. Previous inventories included only a limited number of fuel types and anthropogenic emissions were mapped using national population proxies which may distort the geographical distribution within countries. In this study, a sub-national disaggregation method (SDM) was applied to establish a global 0.1°×0.1° geo-referenced inventory of fuel combustion (PKU-FUEL) and a corresponding CO2 emission inventory (PKU-CO2) based upon 64 fuel sub-types for the year 2007. Uncertainties of the new inventories were evaluated using a Monte Carlo method. The total combustion CO2 emission in 2007 was 11.2 (9.11 and 13.3 as 5th and 95th percentiles) Pg C yr−1. By replacing national disaggregation with sub-national disaggregation in this study, the average 95th minus 5th percentile ranges of CO2 emission for all grids can be reduced from 417 to 68.2 Mg km−2 yr−1, indicating a significant reduction in uncertainty, because the uneven distribution of per-capita fuel consumptions within countries has been taken into account by using the sub-national fuel consumption data directly. Significant difference in per-capita CO2 emissions between urban and rural areas was found in developing nations (2.09 vs. 0.600 Mg C cap−1 yr−1), but not in developed ones (3.57 vs. 3.42 Mg C cap−1 yr−1), suggesting strong influence of the rapid urbanization of these countries on the carbon emission. By using the CO2 emission product, a new spatial pattern of terrestrial carbon sink was derived and the impact of sub-national disaggregation is discussed.


2021 ◽  
Author(s):  
Ignacio Martin Santos ◽  
Mathew Herrnegger ◽  
Hubert Holzmann

<p>In the last two decades, different climate downscaling initiatives provided climate scenarios for Europe. The most recent initiative, CORDEX, provides Regional Climate Model (RCM) data for Europe with a spatial resolution of 12.5 km, while the previous initiative, ENSEMBLES, had a spatial resolution of 25 km. They are based on different emission scenarios, Representative Concentration Pathways (RCPs) and Special Report on Emission Scenarios (SRES) respectively.</p><p>A study carried out by Stanzel et al. (2018) explored the hydrological impact and discharge projections for the Danube basin upstream of Vienna when using either CORDEX and ENSEMBLES data. This basin covers an area of 101.810<sup></sup>km<sup>2</sup> with a mean annual discharge of 1923 m<sup>3</sup>/s at the basin outlet. The basin is dominated by the Alps, large gradients and is characterized by high annual precipitations sums which provides valuable water resources available along the basin. Hydropower therefore plays an important role and accounts for more than half of the installed power generating capacity for this area. The estimation of hydropower generation under climate change is an important task for planning the future electricity supply, also considering the on-going EU efforts and the “Green Deal” initiative.</p><p>Taking as input the results from Stanzel et al. (2018), we use transfer functions derived from historical discharge and hydropower generation data, to estimate potential changes for the future. The impact of climate change projections of ENSEMBLE and CORDEX in respect to hydropower generation for each basin within the study area is determined. In addition, an assessment of the impact on basins dominated by runoff river plants versus basins dominated by storage plants is considered.</p><p>The good correlation between discharge and hydropower generation found in the historical data suggests that discharge projection characteristics directly affect the future expected hydropower generation. Large uncertainties exist and stem from the ensembles of climate runs, but also from the potential operation modes of the (storage) hydropower plants in the future.</p><p> </p><p> </p><p>References:</p><p>Stanzel, P., Kling, H., 2018. From ENSEMBLES to CORDEX: Evolving climate change projections for Upper Danube River flow. J. Hydrol. 563, 987–999. https://doi.org/10.1016/j.jhydrol.2018.06.057</p><p> </p>


2021 ◽  
Author(s):  
Matthew A. Vaughan ◽  
Danielle L. Dixson

AbstractCoral reef organisms are exposed to both an increasing magnitude of pCO2, and natural fluctuations on a diel scale. For coral reef fishes, one of the most profound effects of ocean acidification is the impact on ecologically important behaviors. Previous behavioral research has primarily been conducted under static pCO2 conditions and have recently come under criticism. Recent studies have provided evidence that the negative impacts on behavior may be reduced under more environmentally realistic, fluctuating conditions. We investigated the impact of both present and future day, static (500 and 1000 μatm) and diel fluctuating (500 ± 200 and 1000 ± 200 μatm) pCO2 on the lateralization and chemosensory behavior of juvenile anemonefish, Amphiprion percula. Our static experimental comparisons support previous findings that under elevated pCO2, fish become un-lateralized and lose the ability to discriminate olfactory cues. Diel-fluctuating pCO2 may aid in mitigating the severity of some behavioral abnormalities such as the chemosensory response, where a preference for predator cues was significantly reduced under a future diel-fluctuating pCO2 regime. This research aids in ground truthing earlier findings and contributes to our growing knowledge of the role of fluctuating conditions.


2021 ◽  
Author(s):  
Sergio Andres Romero-Duque ◽  
Maria Cristina Arenas-Bautista ◽  
Leonardo David Donado

<p>Hydrological cycle dynamics can be simulated through continuous numerical modelling in order to estimate a water budget at different time and spatial scales, taking a specific importance when considering climate change effects on the various processes that take place on a basin. With the purpose of estimating potential impacts of climate change on the basin water balance, the present study takes place on the catchment area of the Carare-Minero river, a basin located in the Middle Magdalena Valley (Colombia), a zone in which important economic activities unfold such as stockbreeding and agriculture, where regional climate change scenarios were made for the precipitation and temperature variables, along with a continuous hydrological modeling of the basin using the HEC-HMS software. The regional scenarios for the precipitation and temperature were developed through statistical downscaling based on General Circulation Models (GCM) of the sixth phase of the Coupled Intercomparison Project (CMIP6), with projections to 2100 for seven of the new set of CO2 emission scenarios, the Shared Socioeconomic Pathways (SSP), that take into account different socioeconomic assumptions for climate policies, with a baseline of 25 years between 1990 and 2014; the emission scenarios evaluated from lowest to highest CO2 emission were SSP1-1.9, SSP1-2.6, SSP4-3.4, SSP2-4.5, SSP4-6.0, SSP3-7.0 and SSP5-8.5. The obtained data were used as an input for the model of the basin in HEC-HMS obtaining a new water balance for each scenario comparing the results with the baseline case for current conditions, resulting in an evapotranspiration increase due to higher temperatures that, alongside changes in precipitation, produces lower flows for the higher SSP’s of SSP5-8.5 and SSP3-7.0, in contrast with the low emission scenarios of SSP1-1.9 and SSP1-2.6 were the changes in temperature and precipitation are less drastic generating minor alterations in the hydrological balance.</p><p>Key words: Hydrological modeling, Middle Magdalena Valley, regional climate change scenarios, water balance.</p>


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