Almeida Prado Jr., F., Athayde, S., Mossa, J., Bohlman, S., Leite, F., & Oliver-Smith, A. (2016). How much is enough? An integrated examination of energy security, economic growth and climate change related to hydropower expansion in Brazil. Renewable and Sustainable Energy Reviews, 53, 1132–1136.
Abstract: Reconciling economic growth and energy supply with the reduction of greenhouse gas emissions and other goals for environmental protection is a major challenge for emerging economies such as Brazil. Establishing energy security standards consistent with realistic economic growth projections while considering climate change requires complex calculations and relies upon risky assumptions. Yet, such calculations and decisions must be made to avoid future energy shortages and economic crises. This paper discusses the current dilemma concerning planning and decision-making for the Brazilian electric sector considering the construction of hydroelectric power plants in the Amazon region, energy security requirements, projected economic growth and climate change feedbacks.
|
Catenazzi, A., & Kupferberg, S. J. (2018). Consequences of dam-altered thermal regimes for a riverine herbivore's digestive efficiency, growth and vulnerability to predation. Freshw Biol, 63(9), 1037–1048.
Abstract: Rivers around the world are undergoing shifts in thermal regime due to climate change and human appropriation of water resources. The local impacts of thermal regime change are challenging to predict because water temperature can influence aquatic organisms and communities at multiple levels simultaneously. For example, thermal change can influence the phenology of periphyton blooms, primary consumer physiology and behaviour, and interspecific interactions with predators. Using tadpoles of the threatened river-breeding foothill yellow-legged frog (Rana boylii, Ranidae), their algal foods and their invertebrate predators, we mimicked dam-induced changes in temperature and observed the outcome of consumer-resource interactions. In stream enclosures, we reared tadpoles across a gradient of cold to warm conditions, quantified the ash content of diet, digestive efficiency and growth rate, and assessed their vulnerability to hemipteran and odonate predators. Tadpoles reared in a cool stream (15.5 degrees C daily mean) digested epilithic periphyton poorly (6.60.4% assimilation efficiency). In contrast, average assimilation efficiency of tadpoles reared at 19 degrees C was 11.60.1%. Access to nutritious diatoms (i.e. dinitrogen-fixing Epithemia spp., Rhopalodiaceae) increased assimilation efficiency to 10.1 +/- 0.1% and 13.8 +/- 0.1% in the cool and warm treatments, respectively. Assimilation efficiency correlated positively with tadpole growth rate (R=0.66, p<.001). The effect of temperature on mortality due to predation was mediated by low tadpole growth rates at cool temperatures and not by the temperature of predator exposure. Non-lethal effects of predators on tadpole growth and tail injury, however, depended on both rearing temperature and exposure temperature. Contrary to the expectation that the cost of predator avoidance behaviours may be greater at warmer exposure temperatures because basal metabolic rates are higher, our results indicated that the energetic cost of foraging less was amplified at cool temperatures. Our results show that when thermal conditions impair digestion in a species' early life stages, recruitment bottlenecks are likely to arise due to the combined negative effects of cool temperatures on assimilation efficiency and growth, and increased predation by invertebrates.
|
Engström, J., & Uvo, C. B. (2016). Effect of Northern Hemisphere Teleconnections on the Hydropower Production in Southern Sweden. J. Water Resour. Plann. Manage., 142(2).
Abstract: Approximately 50% of Sweden's electricity is produced by hydropower. This makes energy production in the country vulnerable to factors affecting water availability. Research has shown a positive correlation between the North Atlantic Oscillation (NAO) and hydropower production in Norway and northern Sweden during winter months. The correlation is, however, weaker in southern Sweden, which indicates that there might be other low-frequency atmospheric drivers (teleconnections) affecting this area. The aim of this paper is to analyze the natural climate forcing that affects hydropower production in southern Sweden on a seasonal basis. This knowledge may be of key importance in improving long-term (seasonal to yearly) water management and planning for electricity production in southern Sweden. The Spearman correlation coefficient was calculated between the principal component time series of electricity production (1999-2010) from 17 hydropower stations in 5 different rivers located in southern Sweden and 5 different teleconnection indices: the NAO, East Atlantic (EA), East Atlantic/Western Russia (EA/WR), Scandinavia (SCA), and Polar/Eurasia (POL). Results show that the impact of teleconnections on hydropower electricity production varies with season. In winter, the NAO shows the strongest positive relation with hydropower electricity production, explaining 24% of the variability in production, while the SCA has an almost as strong (15%) opposite effect. During spring and summer, the EA/WR alone shows a significant negative relation, explaining respectively 9 and 13% of the variance in production. No significant correlation appeared during the fall season.
|
