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This paper examines the current and prospective greenhouse gas (GHG) emissions of e-fuels produced via electrolysis and Fischer–Tropsch synthesis (FTS) for the years 2021, 2030, and 2050 for use in Germany. The GHG emissions are determined by a scenario approach as a combination of a literature-based top-down and bottom-up approach. Considered process steps are the provision of feedstocks, electrolysis (via solid oxide co-electrolysis; SOEC), synthesis (via Fischer–Tropsch synthesis; FTS), e-crude refining, eventual transport to, and use in Germany. The results indicate that the current GHG emissions for e-fuel production in the exemplary export countries Saudi Arabia and Chile are above those of conventional fuels. Scenarios for the production in Germany lead to current GHG emissions of 2.78–3.47 kgCO2-eq/L e-fuel in 2021 as the reference year and 0.064–0.082 kgCO2-eq/L e-fuel in 2050. With a share of 58–96%, according to the respective scenario, the electrolysis is the main determinant of the GHG emissions in the production process. The use of additional renewable energy during the production process in combination with direct air capture (DAC) are the main leverages to reduce GHG emissions. [ABSTRACT FROM AUTHOR]

Greenhouse gas emissions depend on natural and anthropic phenomena; however, to reduce emissions, we can only intervene in terms of anthropic causes. Human activity is very different in various countries and cities. This is mainly due to differences in the type of urban environment, climatic conditions, socioeconomic context, government stability, and other aspects. Urban building energy modeling (UBEM), with a GIS-based approach, allows the evaluation of all the specific characteristics of buildings, population, and urban context that can describe energy use and its spatial distribution within a city. In this paper, a UBEM is developed using the characteristics and consumption of eight typical buildings (archetypes) in the climate zone of Santiago de Chile. The archetype-based UBEM is then applied to the commune of Renca, a critical suburb of Santiago, with the use of QGIS to analyze the energy demand for space heating and the potential for energy saving after four retrofitting interventions. Knowing the costs of the retrofitting interventions and the energy price, the simple payback time was evaluated with the reduction in GHG emissions. Starting from the actual building stock, the results show that the most effective retrofitting intervention for the commune of Renca is the thermal insulation of walls and roofs; due to the type of dwellings, this particular intervention could be more convenient if associated with the installation of solar technologies. This methodology can be replicated with the data used by urban planners and public administrations available for many Chilean cities and in other countries. [ABSTRACT FROM AUTHOR]

Climate change and its effects are one of the main concerns of both administrations and citizens in many countries. One of the most important causes of climate change is greenhouse gas emissions, especially CO2, and its reduction is a target for governments around the world. In this sense, the article aims to measure the regional imbalances in CO2 emissions, through the use of a spatial shift-share analysis of the variable intensity of emissions. This methodology will be applied to the regional emissions of Chile for the year 2014, which will be obtained from the application of a multi-regional input–output model. The results of the paper have been structured in two parts: firstly, regional imported and exported emissions have been estimated, from which the responsibilities of the producer and the consumer were determined. Secondly, the Shift Share analysis has been applied to determine regional imbalances in emissions. Large imbalances have been found in the distribution of the intensity of emissions at a regional level. These imbalances may be due to differences in regional economic and production systems, which are manifested through the components that represent the sectoral structure, the localization economies and the regional effect. [ABSTRACT FROM AUTHOR]

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Forest plantations can substantially contribute to carbon sequestration and greenhouse gas (GHG) mitigation at the country and global scales. Forest fires (especially when combined with droughts) may remarkably reduce such carbon sequestration capability. The IPCC has global-scale estimates for such losses, but they can vary widely depending on crops, climate, topography, and management, among other factors. The IPCC defines a factor for biomass loss as a consequence of forest fires, expressed as a fraction of total biomass. This methodology implies using aggregated data and the default emission factor, which are only recommended for countries where wildfires are not a key category. In Chile, over the last decade, there have been between 5000 and 8000 wildfires annually (an average of 6398 for the period 2011–2020), burning an average of 122,328 hectares each year. Countries may progress in the refinement of such factors depending on the availability and reliability of local values. This paper aims at estimating C f values for the main forest plantation species in Chile, Pinus radiata, Eucalyptus nitens, and Eucalyptus globulus, across different age-classes and forest fire severity. To achieve this aim, we assessed the biomass loss after forest fires for a stratified sample of forest plots for the season 2018–2019. We fitted a model to predict the amount of biomass loss during fires, and in this way, predict the emissions associated with wildfires. The model employs very simple predictive variables, age and species, because statistics for burnt areas in plantations are only provided by age-classes and species, without details about productivity or management. [ABSTRACT FROM AUTHOR]

We present a reliable and robust open dynamic chamber for measuring greenhouse gas exchange in peatlands with minimal disturbance of the ground. This chamber, called the "skirt chamber", is based on a transparent plastic film placed above an open frame made of sparse interwoven wires and expanded around the base of the chamber below a steel chain that ensures contact to the ground, avoiding damage, trenching, and cutting vegetation. Gas exchange is determined using a portable gas analyzer from a mass balance in which the imperfect sealing of the chamber to the ground is quantified through the injection of a methane pulse. The method was tested on a pristine peatland dominated by Sphagnum magellanicum located on Navarino Island in the subantarctic Magellanic ecoregion in Chile. Our results indicate that the skirt chamber allowed the determination of methane fluxes and ecosystem respiration in about 20 min, with a limit of detection of 0.185 mg CH 4 m -2 h -1 and 173 mg CO 2 m -2 h -1 , respectively. We conclude that the skirt chamber is a minimally intrusive, fast, portable, and inexpensive method that allows the quantification of greenhouse gas emissions with high spatial resolution in remote locations and without delay. [ABSTRACT FROM AUTHOR]

In a warming world context, sea surface temperature (SST) off central-south Peru, northern Chile, and farther offshore increases at a slower rate than the global average since several decades (i.e., cools, relative to the global average). This tendency is synchronous with an interdecadal Pacific oscillation (IPO) negative trend since ~1980, which has a cooling signature in the southeastern Pacific. Here, we use a large ensemble of historical coupled model simulations to investigate the relative roles of internal variability (and in particular the IPO) and external forcing in driving this relative regional cooling, and the associated mechanisms. The ensemble mean reproduces the relative cooling, in response to an externally forced southerly wind anomaly, which strengthens the upwelling off Chile in recent decades. This southerly wind anomaly results from the poleward expansion of the Southern Hemisphere Hadley cell. Attribution experiments reveal that this poleward expansion and the resulting enhanced upwelling mostly occur in response to increasing greenhouse gases and stratospheric ozone depletion since ~1980. An oceanic heat budget confirms that the wind-forced upwelling enhancement dominates the relative cooling near the coast. In contrast, a wind-forced deepening of the mixed layer drives the offshore cooling. While internal variability contributes to the spread of tendencies, the ensemble-mean relative cooling in the southeastern Pacific is consistent with observations and occurs irrespectively of the IPO phase, hence, indicating the preeminent role of external forcing. [ABSTRACT FROM AUTHOR]

Background: The main goal of this contribution was to define the ecological niche of the guanaco (Lama guanicoe), to describe potential distributional changes, and to assess the relative importance of niche conservatism and divergence processes between the two lineages described for the species (L.g. cacsilensis and L.g. guanicoe). Methods: We used maximum entropy to model lineage’s climate niche from 3,321 locations throughout continental Chile, and developed future niche models under climate change for two extreme greenhouse gas emission scenarios (RCP2.6 and RCP8.5). We evaluated changes of the environmental niche and future distribution of the largest mammal in the Southern Cone of South America. Evaluation of niche conservatism and divergence were based on identity and background similarity tests. Results: We show that: (a) the current geographic distribution of lineages is associated with different climatic requirements that are related to the geographic areas where these lineages are located; (b) future distribution models predict a decrease in the distribution surface under both scenarios; (c) a 3% decrease of areal protection is expected if the current distribution of protected areas is maintained, and this is expected to occur at the expense of a large reduction of high quality habitats under the best scenario; (d) current and future distribution ranges of guanaco mostly adhere to phylogenetic niche divergence hypotheses between lineages. Discussion: Associating environmental variables with species ecological niche seems to be an important aspect of unveiling the particularities of, both evolutionary patterns and ecological features that species face in a changing environment. We report specific descriptions of how these patterns may play out under the most extreme climate change predictions and provide a grim outlook of the future potential distribution of guanaco in Chile. From an ecological perspective, while a slightly smaller distribution area is expected, this may come with an important reduction of available quality habitats. From the evolutionary perspective, we describe the limitations of this taxon as it experiences forces imposed by climate change dynamics. [ABSTRACT FROM AUTHOR]

Most terrestrial ecosystems support a similar suite of biogeochemical processes largely dependent on the availability of water and labile carbon (C). Here, we explored the biogeochemical potential of soils from Earth's driest ecosystem, the Atacama Desert, characterized by extremely low moisture and organic C. We sampled surface soil horizons from sites ranging from the Atacama's hyper-arid core to less-arid locations at higher elevation that supported sparse vegetation. We performed laboratory incubations and measured fluxes of the greenhouse gases carbon dioxide (CO), nitrous oxide (NO), and methane (CH) as indices of potential biogeochemical activity across this gradient. We were able to stimulate trace gas production at all sites, and treatment responses often suggested the influence of microbial processes. Sites with extant vegetation had higher C concentrations (0.13-0.68%) and produced more CO under oxic than sub-oxic conditions, suggesting the presence of aerobic microbial decomposers. In contrast, abiotic CO production appeared to predominate in the most arid and C-poor (<0.08% C) sites without plants, with one notable exception. Soils were either a weak source or sink of CH under oxic conditions, whereas anoxia stimulated CH production across all sites. Several sites were rich in nitrate, and we stimulated NO fluxes in all soils by headspace manipulation or dissolved organic matter addition. Peak NO fluxes in the most C-poor soil (0.02% C) were very high, exceeding 3 ng nitrogen g h under anoxic conditions. These results provide evidence of resilience of at least some soil biogeochemical capacity to long-term water and C deprivation in the world's driest ecosystem. Atacama soils appear capable of responding biogeochemically to moisture inputs, and could conceivably constitute a regionally-important source of NO under altered rainfall regimes, analogous to other temperate deserts. [ABSTRACT FROM AUTHOR]