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Detlef P. van Vuuren Jason Lowe Elke Stehfest Laila Gohar Andries F. Hof Chris Hope Rachel Warren Malte Meinshausen Gian-Kasper Plattner 《Climatic change》2011,104(2):255-285
Integrated assessment models (IAMs) are regularly used to evaluate different policies of future emissions reductions. Since
the global costs associated with these policies are immense, it is vital that the uncertainties in IAMs are quantified and
understood. We first demonstrate the significant spread in the climate system and carbon cycle components of several contemporary
IAMs. We then examine these components in more detail to understand the causes of differences, comparing the results with
more complex climate models and earth system models (ESMs), where available. Our results show that in most cases the outcomes
of IAMs are within the range of the outcomes of complex models, but differences are large enough to matter for policy advice.
There are areas where IAMs would benefit from improvements (e.g. climate sensitivity, inertia in climate response, carbon
cycle feedbacks). In some cases, additional climate model experiments are needed to be able to tune some of these improvements.
This will require better communication between the IAM and ESM development communities. 相似文献
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Contributions of individual countries?? emissions to climate change and their uncertainty 总被引：1，自引：0，他引：1
Niklas H?hne Helcio Blum Jan Fuglestvedt Ragnhild Bieltvedt Skeie Atsushi Kurosawa Guoquan Hu Jason Lowe Laila Gohar Ben Matthews Ana Claudia Nioac de Salles Christian Ellermann 《Climatic change》2011,106(3):359-391
We have compiled historical greenhouse gas emissions and their uncertainties on country and sector level and assessed their contribution to cumulative emissions and to global average temperature increase in the past and for a the future emission scenario. We find that uncertainty in historical contribution estimates differs between countries due to different shares of greenhouse gases and time development of emissions. Although historical emissions in the distant past are very uncertain, their influence on countries?? or sectors?? contributions to temperature increase is relatively small in most cases, because these results are dominated by recent (high) emissions. For relative contributions to cumulative emissions and temperature rise, the uncertainty introduced by unknown historical emissions is larger than the uncertainty introduced by the use of different climate models. The choice of different parameters in the calculation of relative contributions is most relevant for countries that are different from the world average in greenhouse gas mix and timing of emissions. The choice of the indicator (cumulative GWP weighted emissions or temperature increase) is very important for a few countries (altering contributions up to a factor of 2) and could be considered small for most countries (in the order of 10%). The choice of the year, from which to start accounting for emissions (e.g. 1750 or 1990), is important for many countries, up to a factor of 2.2 and on average of around 1.3. Including or excluding land-use change and forestry or non-CO2 gases changes relative contributions dramatically for a third of the countries (by a factor of 5 to a factor of 90). Industrialised countries started to increase CO2 emissions from energy use much earlier. Developing countries?? emissions from land-use change and forestry as well as of CH4 and N2O were substantial before their emissions from energy use. 相似文献
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N. Ranger L. K. Gohar J. A. Lowe S. C. B. Raper A. Bowen R. E. Ward 《Climatic change》2012,111(3-4):973-981
This study explores the feasibility of limiting increases in global temperature to 1.5°C above pre-industrial levels. A probabilistic simple climate model is used to identify emissions paths that offer at least a 50% chance of achieving this goal. We conclude that it is more likely than not that warming would exceed 1.5°C, at least temporarily, under plausible mitigation scenarios. We have identified three criteria of emissions paths that could meet the 1.5°C goal with a temporary overshoot of no more than 50 years: early and strong reductions in emissions, with global emissions peaking in 2015 and falling to at most 44–48 GtCO2e in 2020; rapid reductions in annual global emissions after 2020 (of at least 3–4% per year); very low annual global emissions by 2100 (less than 2–4 GtCO2e) and falling to zero (or below) in the 22nd century. The feasibility of these characteristics is uncertain. We conclude that the proposed date of review of the 1.5°C goal, set at 2015, may be too late to achieve the necessary scaling up of emissions cuts to achieve this goal. 相似文献
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E. A. El-Bestawy Y. M. Gohar S. M. Wefky 《International Journal of Environmental Science and Technology》2017,14(3):497-508
The present study aimed to investigate and optimize the promising antagonistic activity of the exogenous Enterococcus faecium S29 (EU 158188) isolated from the heavily polluted coastal waters of Alexandria, Egypt. Statistical designs, mutations and immobilization were used as optimization procedures. Cells grown in Luria-Bertani and/or UV-treated medium showed optimum activity compared to those grown under basal conditions or ethidium bromide treatment as well as wild-type variants. Immobilization decreased the antagonistic activity of E. faecium compared to their free cells. Ethyl acetate extract (12 organic compounds) exhibited the highest antimicrobial activity and was dominated by phenol (52.11%) and 1, 2 Benzenedicarboxylic acid, diisooctyl ester (29.44%) with molecular weights 94 and 390.28, respectively. Thin-layer chromatography (TLC) fractionation of the bioactive compounds showed two spots with RF: 0.32 and 0.61 with the latter exhibits a broad spectrum of antagonistic activity against six reference pathogens {Staphylococcus aureus (ATCC 6538), Streptococcus faecalis (ATCC 8043), Pseudomonas aeruginosa (ATCC 8739), Escherichia coli (ATCC 8739), Micrococcus luteus (ATCC 10240) and Candida albicans}. The yellow gelatinous purified compound was characterized by an aromatic odor; λ max = 0.629 at 210 nm and IR spectrum [IR (K Br): 1750 ester]. 相似文献
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Gohar Ghazaryan Olena Dubovyk Valerie Graw Nataliia Kussul Jürgen Schellberg 《地理信息系统科学与遥感》2020,57(5):704-718
ABSTRACT Globally, drought constitutes a serious threat to food and water security. The complexity and multivariate nature of drought challenges its assessment, especially at local scales. The study aimed to assess spatiotemporal patterns of crop condition and drought impact at the spatial scale of field management units with a combined use of time-series from optical (Landsat, MODIS, Sentinel-2) and Synthetic Aperture Radar (SAR) (Sentinel 1) data. Several indicators were derived such as Normalized Difference Vegetation Index (NDVI), Normalized Difference Moisture Index (NDMI), Land Surface Temperature (LST), Tasseled cap indices and Sentinel-1 based backscattering intensity and relative surface moisture. We used logistic regression to evaluate the drought-induced variability of remotely sensed parameters estimated for different phases of crop growth. The parameters with the highest prediction rate were further used to estimate thresholds for drought/non-drought classification. The models were evaluated using the area under the receiver operating characteristic curve and validated with in-situ data. The results revealed that not all remotely sensed variables respond in the same manner to drought conditions. Growing season maximum NDVI and NDMI (70–75%) and SAR derived metrics (60%) reflect specifically the impact of agricultural drought. These metrics also depict stress affected areas with a larger spatial extent. LST was a useful indicator of crop condition especially for maize and sunflower with prediction rates of 86% and 71%, respectively. The developed approach can be further used to assess crop condition and to support decision-making in areas which are more susceptible and vulnerable to drought. 相似文献
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We study the quantum tunneling of scalars from charged accelerating and rotating black hole with NUT parameter. For this purpose we use the charged Klein-Gordon equation. We apply WKB approximation and the Hamilton-Jacobi method to solve charged Klein-Gordon equation. We find the tunneling probability of outgoing charged scalars from the event horizon of this black hole, and hence the Hawking temperature for this black hole 相似文献
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