Search

Human societies derive economic benefit from marine systems, yet these benefits may be modified as humans drive environmental change. Here, we conducted the first systematic review of literature on the potential economic effects of ocean acidification. We identified that while there is a growing literature discussing this topic, assessments of the direction and magnitude of anticipated economic change remain limited. The few assessments which have been conducted indicate largely negative economic effects of ocean acidification. Insights are, however, limited as the scope of the studies remains restricted. We propose that understanding of this topic will benefit from using standard approaches (e.g. timescales and emissions scenarios) to consider an increasing range of species/habitats and ecosystem services over a range of spatial scales. The resulting understanding could inform decisions such that we maintain, or enhance, economic services obtained from future marine environments. [ABSTRACT FROM AUTHOR]

This paper provides an account of urban greenhouse gas (GHG) emissions from 40 countries in Europe and examines covariates of emissions levels. We use a 'top-down' analysis of emissions as spatially reported in the Emission Dataset for Global Atmospheric Research supplemented by Carbon Monitoring for Action from 1153 European cities larger than 50 000 population in 2000 (comprising >81 % of the total European urban population). Urban areas are defined spatially and demographically by the Global Rural Urban Mapping Project. We compare these results with 'bottom-up' carbon accounting method results for cities in the region. Our results suggest that direct (Scopes 1 and 2) GHG emissions from urban areas range between 44 and 54 % of total anthropogenic emissions for the region. While individual urban GHG footprints vary from bottom-up studies, both the mean differences and the regional energy-related GHG emission share support previous findings. Correlation analysis indicates that the urban GHG emissions in Europe are mainly influenced by population size, density, and income and not by biophysical conditions. We argue that these data and methods of analysis are best used at the regional or higher scales. [ABSTRACT FROM AUTHOR]

The EU Emissions Trading System (ETS) demonstrated the ability to design and launch a large-scale trading system in a short period of time. The path from initial reticence about emissions trading to implementation of the world's largest program is an important history. Three issues play a large role in the evaluation of the program to date and its on-going development: allocation plans, cost uncertainty, and leakage of emissions to abroad. Decisions in Phase I and II (2005-2012) were responsive to questions of political feasibility and implementation, but some of these decisions including allocation in particular will be substantially revised in Phase III (2013-2020). [ABSTRACT FROM AUTHOR]

The article reflects on the different studies that uses the sentence, "we are evaporating our coal mines into the air," or part of it, to introduce or to illustrate discussions of the anthropogenic production of carbon dioxide from fossil fuels. Such studies focus on the effect of carbon dioxide on the climate of the earth. Among which is the classical 1896 paper of Svante Arrhenius, the context of which was brought on their discussion with his colleague at the Stockholm Physics Society, wherein Arvin Högbom presented a calculation of the rates of all the processes that might change the concentration of carbon dioxide in the atmosphere.

We used the Agriculture and Land Use National Greenhouse Gas Inventory Software to estimate the total greenhouse gas (GHG) emissions from the Nigerian agriculture sector in 2010. We went ahead to project future GHG emissions up to 2050. Two alternative GHG mitigation scenarios such as moderate (MS) and aggressive (AS) scenarios were developed and examined. Our results showed that total GHG emissions from Nigerian agriculture in 2010 were around 34.9 million tonnes of carbon dioxide equivalent. GHG emissions from livestock accounted for about 69.2 % of the total emissions, making it the largest source of GHG emissions in the sector. Nigeria's agriculture GHG emissions are expected to increase by 94 % in 2050 relative to 2010 levels. Mitigation strategies in the Nigerian agriculture sector that do not compromise food security are limited. However, with the implementation of different GHG mitigation strategies in the alternative scenarios, emissions are expected to fall by around 13.2 % and 26.7 % by 2050 in the MS and AS, respectively, compared to the baseline scenario. While the mitigation potentials are significant, we argue that robust and dedicated policies are required to accelerate climate-smart agriculture in Nigeria. [ABSTRACT FROM AUTHOR]

Climate change is occurring largely as a result of increasing CO emissions whose reduction requires greater efficiency in energy production and use and diversification of energy sources away from fossil fuels. These issues were central to the United Nation climate change discussions in Durban in December 2011 where it was agreed that a legally binding agreement to decrease greenhouse gas emissions should be reached by 2015. In the interim, nations were left with the agreement reached at the analogous 2009 Copenhagen and 2010 Cancun meetings that atmospheric CO levels should be constrained to limit the global temperature rise to 2 °C. However, the route to this objective was largely left to individual nations to decide. It is within this context that options for reduction in the 95 % fossil fuel dependency and high CO emissivity of the Australian energy profile using current technologies are considered. It is shown that electricity generation in particular presents significant options for changing to a less fossil fuel dependent and CO emissive energy profile. [ABSTRACT FROM AUTHOR]

Organic farming is believed to improve soil fertility by enhancing soil organic matter (SOM) contents. An important co-benefit would be the sequestration of carbon from atmospheric CO2. Such a positive effect has been suggested based on data from field experiments though many studies were not designed to address the issue of carbon sequestration. The aim of our study was to examine published data in order to identify possible flaws such as missing a proper baseline, carbon mass measurements, or lack of a clear distinction between conventional and organic farming practices, thereby attributing effects of specific practices to organic farming, which are not uniquely organic. A total of 68 data sets were analyzed from 32 peer-reviewed publications aiming to compare conventional with organic farming. The analysis revealed that after conversion, soil C content (SOC) in organic systems increased annually by 2.2% on average, whereas in conventional systems SOC did not change significantly. The majority of publications reported SOC concentrations rather than amounts thus neglecting possible changes in soil bulk density. 34 out of 68 data sets missed a true control with well-defined starting conditions. In 37 out of 50 cases, the amount of organic fertilizer in the organic system exceeded that applied in the compared conventional system, and in half of the cases crop rotations differed between systems. In the few studies where crop rotation and organic fertilization were comparable in both systems no consistent difference in SOC was found. From this data analysis, we conclude that the claim for beneficial effects of organic farming on SOC is premature and that reported advantages of organic farming for SOC are largely determined by higher and often disproportionate application of organic fertilizer compared to conventional farming. [ABSTRACT FROM AUTHOR]

There is a need to reduce the amount of fossil energy used for transport, both because of the easily available fossil fuel is becoming sparser and because of climate concerns. In this article, the concept of ''peak oil'' is briefly presented. Second, a practical approach to reduction of fossil fuel use for transport elaborated by two British commissions is presented. A key feature is the introduction of electric cars. This raises the third issue covered in this article: namely, how battery technology is going to meet the increasing needs posed by the transport sector. [ABSTRACT FROM AUTHOR]

On the political stage the climate change debate used to center primarily around intergenerational issues, particularly whether aggressive abatement action was even warranted-on the basis of uncertain scientific projections. In recent years, influenced by both improved scientific knowledge and greater emphasis on the precautionary principle, within policy circles, climate change has become more widely acceptedas a significant threat to ecological sustainability. Accordingly, the focus of debate has gradually shifted to intragenerational concerns, with the issue of equitable burden sharing in terms of greenhouse gas emission abatement emerging as a point of primary contention. This paper integrates scientific and political analyses to explore a number of questions which have been raised during the debate. In particular, we draw on carbon cycle modelling to investigate effective and equitable strategies of emission reduction consistent with stabilization of atmospheric CO2 concentrations at 750 ppmv by 2100. [ABSTRACT FROM AUTHOR]

This paper compares transient carbon fluxes to and from forests during climatic change in a pure natural model of ecosystem adjustment and also in a model that captures the human response to these changes. Both models incorporate forest dieback and regeneration, forest redistribution, and changes in ecosystem production during climatic change. The natural model predicts that forested ecosystems in the United States will release 2.5 to 6.3 Pg carbon during the next 7 decades under climatic change. The model including human response shows that markets will mitigate, and even reverse, these fluxes by managing some forests for timber and storing carbon in wood products. [ABSTRACT FROM AUTHOR]

This paper shows that the use of ethyl alcohol and sugar cane bagasse as fuel substitutions for gasoline, and natural gas, fuel oil or coal, can have an important role to avoid GHG emissions. The Brazilian Alcohol program and the use of sugar cane bagasse for generating electricity may prove to be an important alternative for the reduction of GHG emissions. Large-scale production and the use of renewable energy from biomass may qualify Brazil for recognition at an international level. It is shown that the cost of alcohol is higher than that of gasoline with the present low price of oil on the international market, but the costs could be reduced by feasible technological improvements. [ABSTRACT FROM AUTHOR]

This paper describes the developments that transformed the global warming problem from that arising solely from CO2 increase to the trace-gas greenhouse effect problem in which several non-CO2 gases, CFCs, CH4, N2O, O3 and others contribute as much as CO2. Observed trace-gasincreases, including CO2 increase, since the mid-19th century have enhanced the atmospheric greenhouse effect, Ga, (3 130 1 5 W m-2) by about 2%. Without other competing factors, this heating should have committed the planet to a warming of about 1 to 1.5 K. The added radiative energy is maximum in the low latitudes and about a factor of two smaller in the polar regions. The largest effect of the warming is increased back radiation at the surface by as much as 6 to 8 W m-2 per degree warming. Not all of this increased energy is balanced by surface emission; evaporation (and hence precipitation) increases to restore surface energy balance, by as much as 2 to 4% per degree warming. The increase in evaporation along with the increase in saturation vapor pressure of the warmer troposphere, contributes through the atmospheric dynamics to an increase in water vapor. This water vapor feedback enhances Ga by another 1% per degree warming. Our ability to predict regional and transient effects, depends critically on resolving a number of outstanding issues, including: i) Aerosol and stratosphericozone effects; ii) Response of the tropical convective-cirrus clouds, the extra-tropical storm-track systems and persistent coastal stratus to both global warming and to regional emissions of aerosols; iii)The causes of excess solar absorption in clouds; and iv) Upper troposphere water vapor feedback effects. [ABSTRACT FROM AUTHOR]

This paper is based on the commemorative lecture which was deliveredat the award ceremony of the Volvo Environmental Prize. The author describes his early attempt to study the greenhouse effect using a one-dimensional model of radiative, convective equilibrium of the atmosphere. This is followed by the description of a recent study of globalwarming which employs a general circulation model of the coupled atmosphere-ocean-land surface system developed at the Geophysical Fluid Dynamics Laboratory (GFDL). In particular, the study attempts to elucidate the role of oceanic and land surface processes in shaping the response of surface air temperature to a gradual increase in atmospheric carbon dioxide (CO2). [ABSTRACT FROM AUTHOR]

The so-called "greenhouse gases", or "hothouse" gases as Arrhenius called them, are not the only radiatively active substances being added to the atmosphere by humans. A different class of matter, aerosols, consisting of small particles of condensed matter suspended in the air has several climatic effects besides a small amount of absorptionof infrared radiation. The particles that constitute the smoke and haze of products of atmospheric chemical reactions, e.g. of sulfur dioxide from burning of coal. The direct effect of aerosols on the earth's heat balance consists of their reflection of solar radiation back to space. Their indirect effect derives from their roles as the nuclei around which cloud droplets form. Adding more of these cloud condensation nuclei increases the reflectivity of clouds, a very important determinant of climate as discussed by Arrhenius. Aerosols may also influence the longevity of clouds and thus the fraction of earth covered by them-the "nebulosity" mentioned by Arrhenius. An additional direct effect of aerosols is light absorption by black soot particles, which can influence both clear and cloudy skies. Although quantitative assessments of these effects of aerosols have been developed in recent years, there have been extensive studies and observations of their roles in climate, particularly the ancient observation that large volcanic eruptions caused large-scale cooling to occur. Interestingly, several of the early key studies were also conducted in Sweden, notably by Angstrom and Bergeron. The present understanding is that man-made aerosols have a cooling effect, but that it is somewhat smaller in the global mean than the warming effect of the man-made greenhouse gases and is spatially and temporally very different. Thus, no simple cancellation of the two effects can occur. This paper reviews the historical development of the understanding and quantification of direct aerosol effects on climate. Particular attention will bep [ABSTRACT FROM AUTHOR]

The agenda of global carbon cycle research features two fundamental problems. The first concerns the direct response of the carbon systemto the anthropogenic perturbation, i.e. how is the excess carbon dioxide emitted by fossil fuel burning and from changes in land use (i.e. deforestation) distributed between atmosphere, land and the ocean, and how is this distribution changing as a function of time? The second problem addresses the feedbacks, i.e. how do changes in climate feedback on the natural carbon cycle and may thus lead to variations in the atmospheric CO{sub}2{end} concentration? This paper reviews some of the observational constraints to addressing these problems: (i)The direct atmospheric observations and the ice-core measurements which document the CO{sub}2{end} increase during the last 100 years; (ii) the role of the ocean in the current atmospheric CO{sub}2{end} budget as determined from model simulations and by new methods based on observations of oxygen and carbon isotopes; and (iii) the spatial information revealed by the global CO{sub}2{end} monitoring networks. One hundred years ago, Arrhenius and his geologist colleague Hogbom were both aware of the major processes which control the atmospheric CO{sub}2{end} concentration, however, they were more interested in the long-term aspects and did not perceive the industrial emissions as an immediate threat to the global climate. Today, we can quantify and model the direct response to anthropogenic perturbation, although important uncertainties still exist, in particular with respect to terrestrial biospheric processes. However, our understanding of the multitude of climatic feedbacks on the carbon cycle is very limited. This problem constitutes a challenge that will remain on the scientific agenda for the next decades. [ABSTRACT FROM AUTHOR]

The authors argue that the consensual scientific knowledge presented by the Intergovernmental Panel on Climate Change (IPCC) on climate change and its effect is the not absolute truth. They contend that consensual scientific knowledge represents minimum common denominator because the scientists' opinion may mismatch due to their multiplicity and complexity. The authors commend IPCC for proving that climate change is occurring as a result of carbon dioxide emissions. They say that IPCC documents are not clear.