Welfare effects of green tax reforms in one sector and two sector dynamic economies

The main focus of this paper is twofold. First is to design Pigouvian taxes for different kinds of environmental external effects on the market economy in order to be possible to say what is the relevant information in each situation. Second is to address the question of the welfare effects of using close to Pigouvian taxes in real economies. This is done by considering more general conditions than those used by Aronsson et al. (2003). In particular, we take the ecosystem dynamics as being density dependent, and we assume that there are errors in measuring both the consumers marginal utility of nature and its regeneration rate. Additionally, we derive cost benefit rules for a green tax reform on the context of a two sector economy, in particular, a final goods sector and a knowledge sector, considering two externalities - one environmental externality and one technology externality.Environmental externalities; Non-Pigouvian taxes; social cost benefit analysis

Optimal ecosystem management with structural dynamics

We address the problem of optimal management of a self organizing ecosystem along ecological succession. A dynamic carrying capacity is interpreted as depicting the dynamics of habitat creation and occupation along ecological succession. The ecosystem may have three growth modes: pure compensation (concave ecosystem regeneration function), depensation (convex-concave regeneration function) and critical depensation (additionally having negative growth rates for low biomass). We analyse the optimal policies for the management of the ecosystem for the three growth modes. Accordingly, we prove the existence of a Skiba points for certain types of ecosystems. Further, we compare usual golden rule paths with the derived optimal policies near the Skiba points.Ecosystem management; habitat creation; optimal policies; Skiba point

Analysis of green net national product and genuine saving in Portugal, 1991 - 2005

The context of this paper is the measurement of welfare and weak sustainability, defined as non-declining utility, in dynamic economies, i.e., green, environmental or comprehensive accounting. We estimate the green net national product and genuine saving for Portugal 1991-2005, accounting for the disamenity of air pollution emissions, the depreciation of commercial forests - pine and eucalyptus -, the value of time (through technological progress), excluding the effect of business cycles and discussing the assumptions behind the usual terms included in the empirics of comprehensive accounting. For the accounting period considered we find that both GNNP and GS are positive, thereby indicating no sustainability problem in Portugal, although both GNNP and GS depict a trend towards unsustainability. Excluding technological progress there is a contradiction in the sustainability message: GS is negative after 2002, whereas GNNP is always positive, indicating that welfare increased.Welfare measures; green accounting; technological progress; business cycles

Electricity consumption described by urban scaling laws: the case of Portugal using two definitions of urban area

Peer Reviewe

From History to Soil and Back Again

UIDB/04209/2020 UIDP/04209/2020This research explains what happened to agricultural soil fertility during the "Campanha do Trigo" (Wheat Campaign) in Portugal, which began in 1929. It is commonly understood that the excessive expansion of wheat crops during the fascist "Estado Novo" (New State) regime led to the degradation of soils in the southern half of Portugal. This relationship, however, has never been questioned before. This article extends the narrative back into the last half of the nineteenth century in search of the origin of processes that gradually intensified throughout the country. In short, expansion of the cultivated area in association with the inadequate intensification of crop rotations over about 80 years, from the 1870s onward, including in non-wheat areas, strongly accentuated soil erosion and made organic fertilization progressively less effective. These transformations were only partially offset by chemical fertilization. Nitrogen and phosphorus were the key factors in this historical process. Focusing on the cultivation system and soil dynamics allows the successive integration of various kinds of historical evidence and sources. From an environmental question-why did agricultural soil degrade?-this article explores soil degradation over time and space, and assesses its social and biophysical impacts. At the same time, it addresses the history of agriculture in Portugal and its disciplinary foundations.authorsversionpublishe

Constraints on Dematerialisation and Allocation of Natural Capital along a Sustainable Growth Path

This paper extends the neoclassical growth model with natural capital by introducing two new concepts: allocation of natural capital and materialization. We consider that anthropogenic environmental impact is correlated with the throughput of the economy (materialisation). Materialisation is the material throughput per unit of economic activity. We capture the effect of the reduction of this throughput dematerialisation in the elasticities of materialisation and aggregate environmental impact. In our framework the fraction of natural capital devoted to production does not provide direct environmental services nor does it contribute to ecosystem functioning namely affecting the carrying capacity of natural capital.We analyse an optimal sustainable growth path, in the context of exogenous technological change. Our main conclusion is that the ratio of dematerialisation elasticities must equal the inverse of the share of natural capital in order to assure unbounded economic growth with constant natural capital

“BalSim”: A Carbon, Nitrogen and Greenhouse Gas Mass Balance Model for Pastures

Animal production systems are increasingly required to co-produce meat products and other ecosystem services. Sown biodiverse pastures (SBP) were developed in Portugal as an improvement over semi-natural pastures (SNP). SBP increase yields and animal intake during grazing, are substantial carbon sinks, and the abundance of legumes in the mixtures provides plants with a biological source of nitrogen. However, the data available and the data demands of most models make integrated modelling of these effects difficult. Here, we developed “BalSim”, a mass balance approach for the estimation of carbon and nitrogen flows and the direct greenhouse gas (GHG) balance of the two production systems. Results show that, on average, the on-farm GHG balance is 2.6 and 0.8 t CO2e/ha.yr for SBP and SNP, respectively. Ignoring the effects of carbon sequestration, and taking into account only non-CO2 emissions, the systems are responsible for 17.0 and 16.3 kg CO2e/kg live weight.yr. The annual analysis showed that non-CO2 emissions were highest in a drought year due to decreased yield and stocking rate. We also showed through scenario analysis that matching the grazing level to the yield is crucial to minimize emissions and ensure reduced feed supplementation while maintaining high soil carbon stocks.info:eu-repo/semantics/publishedVersio

Highly productive sown biodiverse pastures with low invasion risk

Driscoll et al. (1) have recently drawn attention to the risk of new pasture plants becoming invasive, because the same biological traits that promote pasture productivity may also facilitate the invasion of natural areas. The authors indicate some aspects that could mitigate the risk of invasion: namely, the use of native species to develop new pasture plants, the avoidance of new characteristics associated with environmental weeds, and the selection of new characteristics that limit invasion risk. Here we describe a system that meets the above criteria—specifically, the last one—through the existence of a mismatch between the environmental conditions found in managed and in natural areas, such that improved pasture plants face environmental limitations in natural areas while keeping a high performance in managed ones. The system of sown biodiverse permanent pastures rich in legumes (SBPPRL) has been successfully implemented in Portugal on farms in Mediterranean climate areas (2, 3). SBPPRL were developed by Portuguese agronomists, namely David Crespo, as a response to the low levels of productivity and feed quality obtained in seminatural pastures. The pastures’ low performance results from endogenous low soil fertility and historical land use practices that depleted soil nutrients, disrupted soil structure, and caused plant community impoverishment, especially the decline of legume species (4). SBPPRL consist in mixtures of up to 20 taxa of grasses and legumes, each mixture tailored to local environmental conditions (e.g., precipitation and soil texture) to best cover the available environmental niches. Seed mixtures include autochthonous (the majority) and exotic species (all native to the Mediterranean basin) selected to achieve the best performance in soils with enhanced fertility. Legumes and associated Rhizobium fix atmospheric nitrogen, making the system self-sufficient in nitrogen, but require an external input of phosphorus (a limiting nutrient in Mediterranean soils) and the correction of soil acidity for optimal legume growth (5). As result, improved cultivars are not competitive in oligotrophic environments with acidic soils (i.e., natural environments) but outcompete spontaneous pasture plants in managed systems. This aspect not only contributes to the longterm persistence of SBPPRL but also to reducing their invasive risk. In fact, the older SBPPRL are now over 30 y old, and there are no reports of exotic pasture species establishment outside ruderal or managed pasture habitats (i.e., in natural ecosystems). Moreover, SBPPRL offer an alternative for sustainable intensification by combining higher pasture productivity (i.e., socio-economic benefits) with environmental benefits that emerge as positive externalities, such as soil carbon sequestration and soil restoration, both associated with the absence of tillage in SBPPRL and the accumulation of soil organic matter (3, 4). Additionally, the use of phosphorus fertilization is more than compensated by the avoided impacts of using nitrogen fertilizers (otherwise required either to produce concentrate feed or fertilize pastures), and potential leaching of phosphorus is mitigated by increased soil organic matter (4). The opportunities for society of SBPPRL were acknowledged by the Portuguese Carbon Fund* through the payment of soil carbon sequestration (2009– 2014) in around 50,000 ha, in an estimated total of 1 million tons of CO2 (2).info:eu-repo/semantics/publishedVersio

Exploring the links between total factor productivity, final-to-useful exergy efficiency, and economic growth: Case study Portugal 1960-2014

Mainstream economic growth models downplay the role of energy, while attributing most of growth to an exogenous residual – total factor productivity (TFP). This makes them unsuitable to tackle the challenge of marrying sustainability and economic development targets. Meanwhile, research suggests that measuring energy at the stage where it’s actually productive (useful), and in exergy terms (in thermodynamics, the potential to do work), unlocks new insights concerning energy’s strong link with economic output. In this work we test for relationship linking TFP and final-to-useful (F-to-U) exergy efficiency, resorting to both observational and statistical methods (cointegration). Several models are considered, assessing the impact of: a) disaggregating capital inputs (i.e. buildings, stationary, non-stationary); b) quality-adjusting labour; c) disaggregating F-to-U exergy efficiency (stationary and non-stationary end-uses). Results for Portugal (1960-2014) show that TFP can be proxied by changes in F-to-U exergy efficiency, namely for stationary end-uses. This link is strengthened when disaggregate capital, and schooling-corrected labour measures are considered. When TFP is estimated as a function of F-to-U exergy efficiency, virtually all of long-term economic growth is explained by directly measurable capital, labour, and exergy efficiency in production. Resulting models provide satisfactory explanations of economic growth, founded on energy use and efficiency