Search NASA⌕ Search

SEARCH · Search NASA

Results for “FOSSIL FUELS”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14

Early retirement of power plants in climate mitigation scenarios

International efforts to avoid dangerous climate change aim for large and rapid reductions of fossil fuel CO 2 emissions worldwide, including nearly complete decarbonization of the electric power sector. However, achieving such rapid reductions may depend on early retirement of coal- and natural gas-fired power plants. Here, we analyze future fossil fuel electricity demand in 171 energy-emissions scenarios from Integrated Assessment Models (IAMs), evaluating the implicit retirements and/or reduced operation of generating infrastructure. Although IAMs calculate retirements endogenously, the structure and methods of each model differ; we use a standard approach to infer retirements in outputs from all six major IAMs and—unlike the IAMs themselves—we begin with the age distribution and region-specific operating capacities of the existing power fleet. We find that coal-fired power plants in scenarios consistent with international climate targets (i.e. keeping global warming well-below 2 °C or 1.5 °C) retire one to three decades earlier than historically has been the case. If plants are built to meet projected fossil electricity demand and instead allowed to operate at the level and over the lifetimes they have historically, the roughly 200 Gt CO 2 of additional emissions this century would be incompatible with keeping global warming well-below 2 °C. Thus, ambitious climate mitigation scenarios entail drastic, and perhaps un-appreciated, changes in the operating and/or retirement schedules of power infrastructure.

20 FOSSIL-FUELED POWER PLANTS↗

Scenarios of Building Energy Demand for China with a Detailed Regional Representation

Building energy consumption currently accounts for 28% of China’s total energy use and is expected to continue to grow induced by floorspace expansion, income growth, and population change. Fuel sources and building services are also evolving over time as well as across regions and building types. To understand sectoral and regional difference in building energy use and how socioeconomic, physical, and technological development influence the evolution of the Chinese building sector, this study developed a building energy use model for China downscaled into four climate regions under an integrated assessment framework. Three building types (rural residential, urban residential, and commercial) were modeled specifically in each climate region. Our study finds that the Cold and Hot Summer Cold Winter regions lead in total building energy use. The impact of climate change on heating energy use is more significant than that of cooling energy use in most climate regions. Both rural and urban households will experience fuel switch from fossil fuel to cleaner fuels. Commercial buildings will experience rapid growth in electrification and energy intensity. Improved understanding of Chinese buildings with climate change highlighted in this study will help policy makers develop targeted policies and prioritize building energy efficiency measures.

building energy use↗

Desulfurization of Liquid Hydrocarbon Fuels with Microporous and Mesoporous Materials: Metal-Organic Frameworks, Zeolites, and Mesoporous Silicas

This review discusses potential microporous and mesoporous materials that can address the issue of sulfur reduction via adsorptive desulfurization (ADS) with a focus on liquid fuels. During the transition to cleaner energy sources in the face of climate change, liquid fossil fuels will likely continue to provide a significant share of the world’s energy demand. Fossil fuels possess a substantial amount of deleterious sulfur compounds that reduce the efficiency of energy production, damage the environment, and harm human health. There has recently been a large push to address these challenges that sulfur presents. ADS is one of the most promising techniques to reduce the sulfur content of liquid fuels in a cost-effective manner. The three key materials that have attracted a great deal of attention for their application in ADS are metal-organic frameworks (MOFs), zeolites, and mesoporous silicas. These materials have emerged as potential candidates for ADS because of their high surface area, tunable structure, and advantageous porosity. Research interest has been generated around finding unique approaches to modify these materials that increase their selectivity, stability, adsorption capacity, and reusability. A deeper mechanistic understanding of the adsorption of various sulfur compounds on these novel materials has been pursued experimentally and with the aid of models. Here, this review seeks to discuss the recent advances made surrounding the most promising ADS materials while providing an outlook on where advancements still need to be made.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Hydrogen generation via ammonia decomposition on highly efficient and stable Ru-free catalysts: approaching complete conversion at 450 °C

We report Hydrogen (H 2 ) is a prospective zero-carbon and high-energy-density fuel alternative to fossil fuels for generating power and clean energy. Ammonia (NH 3 ) is a promising H 2 (17.7%) carrier, which can easily overcome the challenges associated with H 2 storage and transportation. Thermocatalytic ammonia decomposition reaction (ADR) is an effective way to produce clean H 2 but it relies on the use of expensive and rare ruthenium (Ru)-based catalysts at elevated temperatures (>500 °C), hence is not sustainable and economically feasible. Herein, we report a synergistic strategy to design a heterostructured Ru-free catalyst, consisting of CoNi alloy nanoparticles well-dispersed on a MgO–CeO 2 –SrO mixed oxide support with potassium promotion. The resulting K–CoNi alloy –MgO–CeO 2 –SrO catalyst presents 97.7% and 87.5% NH 3 conversion efficiency at 450 °C at gas hourly space velocities (GHSVs) of 6000- and 12 000-mL h -1 g cat -1 , respectively. At 500 °C, the H 2 production rate (57.75 mmol g cat -1 min -1 ) becomes comparable to that of most of the reported Ru-based catalysts. The catalyst stability has been successfully demonstrated in both a fixed-bed reactor under high pressure (120 h at 5.0 bar) and a membrane reactor prototype (600 h at 1.5 bar) at 500 °C. High-temperature in situ XPS analysis, temperature-programmed desorption/reduction, and density functional theory calculations have been carried out to elucidate the possible active sites and performance enhancement mechanisms. This work highlights the importance of constructing optimal interfaces between active metal nanoparticles and oxide support for boosting the NH 3 to H 2 conversion efficiency and long-term stability.

25 ENERGY STORAGE↗

Future US energy demands based upon traditional consumption patterns lead to requirements which significantly exceed domestic supply

Energy consumption in the United States has risen in response to both increasing population and to increasing levels of affluence. Depletion of domestic energy reserves requires consumption modulation, production of fossil fuels, more efficient conversion techniques, and large scale transitions to non-fossile fuel energy sources. Widening disparity between the wealthy and poor nations of the world contributes to trends that increase the likelihood of group action by the lesser developed countries to achieve political and economic goals. The formation of anticartel cartels is envisioned.

Source record↗

Prevented Mortality and Greenhouse Gas Emissions From Historical and Projected Nuclear Power

In the aftermath of the March 2011 accident at Japan's Fukushima Daiichi nuclear power plant, the future contribution of nuclear power to the global energy supply has become somewhat uncertain. Because nuclear power is an abundant, low-carbon source of base-load power, it could make a large contribution to mitigation of global climate change and air pollution. Using historical production data, we calculate that global nuclear power has prevented an average of 1.84 million air pollution-related deaths and 64 gigatonnes of CO2-equivalent (GtCO2-eq) greenhouse gas (GHG) emissions that would have resulted from fossil fuel burning. On the basis of global projection data that take into account the effects of the Fukushima accident, we find that nuclear power could additionally prevent an average of 420 000−7.04 million deaths and 80−240 GtCO2-eq emissions due to fossil fuels by midcentury, depending on which fuel it replaces. By contrast, we assess that large-scale expansion of unconstrained natural gas use would not mitigate the climate problem and would cause far more deaths than expansion of nuclear power.

nuclear power plants↗

Life cycle impact assessment of artisanal sandstone mining on the environment and health of mine workers

Highlights: • Life cycle assessment (LCA) of artisanal sandstone mining in South Africa • Impact assessment of sandstone mining activities on environment and health • Fossil fuel and coal generated electricity are major non-renewable energy sources • Diesel fuel combustion during transportation phase contributed to major emissions • Silicosis and musculoskeletal problems are most common health issues - Abstract: Artisanal and small scale mining (ASM) is considered as a means to support and improve the quality of rural life, and is often the only activity that local communities have to sustain themselves. It is important to understand the nature of ASM and associated environmental effects in order to make informed decisions on the management, licensing and policy formulation of the ASM sector. Compared to other mined commodities such as, gold or diamond, the studies focusing on environmental and health impacts of sandstone mining are limited. This study used life cycle assessment (LCA) tool to evaluate the overall impact of artisanal sandstone mining (ASAM) on the environment and human health. The impact categories assessed in the study included: resource depletion, global warming, ozone layer depletion and acidification. It was observed that the impact of ASAM on the environment was minimal, however the high physical demand of the work negatively affected the health of the miners. The most common health related issues with the miners was observed to be silicosis and musculoskeletal problems. Fossil fuel used during transportation was observed to be the highest contributor for most of the impact categories.

54 ENVIRONMENTAL SCIENCES↗

Investigation of the Effects of Hydrogen Atoms Concentration on the Tungsten Sigma 5 (310) Symmetric Tilt Grain Boundary Strength

Recently, strict policies are being made by several government agencies, environmentalists, and some people against the usage of fossil fuels as the source of energy generation. Not only because its supply does not meet the booming human population all around the world but also it is not pollution-free; just to mention a few. These setbacks attached to fossil fuels make nuclear fusion energy an important means of energy generation; it is characterized with clean and easy means of energy generation compared to other methods of power production such as hydropower and solar power. The success of fusion power depends on the design of modern fusion materials and the selection of the plasma facing materials (PFMs). ITER and Demonstration Power plant (DEMO) considered Tungsten (W) as part of their PFMs. W is the most preferred plasma facing material (PFM) for the future nuclear fusion reactors such as in the proposed DEMO and ITER- which is at the moment the largest Tokamak nuclear fusion reactor under construction in the world. Tungsten has excellent thermal properties, low-sputtering yield, and high melting point. Hydrogen (H) atoms have an affinity for tungsten grain boundary, and are trapped there permanently. In addition, it makes W prone to failure. In a fusion environment, W is exposed to extremely high fluences of H isotopes and irradiation. The low-energy H isotopes will be retained in the tungsten material leading to the formation of blisters in W and cause degradation of the mechanical and thermal properties of W. For safety reason, the effect of hydrogen atoms concentration at the tungsten S5 (310) grain boundary (GB) needs to be investigated and it will aid in better designing of fusion wall materials. Σ5 (310) is considered in this work because it is one of the most important and dominant GBs in the atomic distribution of materials. GBs affect the strength of W as well. The GBs with superior properties can be increased in the atomic distribution of W relative to others in order to achieve high overall material properties. GBs play a role in determining the properties of materials such as the thermal and electrical conductivity of a material. The crystallography description of the Σ5 (310) grain boundary comprises of Σ, tilt type- symmetric, crystallographic direction [001] and the GB plane. The Σ is related to the coincidence site lattice (CSL) model, which denotes that in a certain orientation between two grains, there are numbers of points where the atoms coincide. For the case of Σ5 (310), the misorientation between the two crystals is 36.9 degree along [001] direction and the GB plane is (310). GB properties differ as result of different sigma values and Σ is the reciprocal of CSL. Thus, Σ5 GB has 1/5 of the atoms in coincident sites. For the case of a tilt boundary, the lattice vector is embedded in the GB plane. Also for a tilt-symmetric GB, the grains directions are mirrored against the GB plane. The classic molecular dynamics method (MD) is an accurate numerical approach that adopts Newton's equation of motion to get atoms trajectories.Studies have been carried out on atomistic simulation of tungsten.The effect of H on GB migration in W was studied by using molecular dynamics simulation and it was discovered that H prevents the GB migration at different H concentrations and temperatures. Others investigated the migration, dissolution and trapping of H in W using MD and first principles method. Atomistic simulations have been used to predict the GB energy in Fe and Mo using embedded atom method (EAM) and it was concluded that the GB energies in the metals are affected more by the orientation of the GB plane than by the misorientation of the lattice. Study was done on symmetric and asymmetric tilt grain boundaries in Cu and Al using MD method and the GB structures and energies were established; EAM was adopted as well. The formation of hydrogen blisters and cracking processes for various tungsten materials were investigated and it was observed that, dopants increase the number of blisters and exfoliations for both stress relieved and recrystallized W. Investigation was carried out on the surface morphology changes in W caused by plasmas heat and particle loadings and their effects on material degradation in ITER. In addition, the study of interactions between low energetic hydrogen and tungsten surface was carried out using molecular dynamics simulations with analytical bond order potential (ABOP) and the results addressed irradiation damage in tungsten. Mechanism of blister formation on W surface was studied using experimental approach and it was observed that the amount of blisters formed depends on the beam fluence. This work investigates the effect of hydrogen atom concentrations at the W Σ5 (310) tilt-symmetric GB on the grain boundary energy and the GB pulling force. (authors)

36 MATERIALS SCIENCE↗

Climate Impact of Primary Plastic Production

Plastics show the strongest production growth of all bulk materials over the last decade. The industry’s current growth trajectory is exponential and plastic production is expected to double or triple by 2050. The rapidly increasing production of plastics and the continued reliance on fossil fuels for production, have contributed to numerous environmental problems and health harms. As a result, plastic pollution has become an increasing threat to natural ecosystems, human health and climate. However, there is a lack of granularity on the contribution of the primary plastics specifically to greenhouse gas (GHG) emissions and their impact on the remaining global carbon budget needed to stay below a 1.5°C or 2°C global average temperature rise. In this report, we explore the contribution of primary plastic production to climate change disaggregated by polymer and technology. To this end, we have developed comprehensive bottom-up modeling of GHG emissions from global primary plastic production, with a special focus on polymer value chains. We have analyzed the results under various growth scenarios in the context of carbon budgets compatible with a 1.5°C global trajectory. Modeling includes the material flows of all production stages, processes and technologies used in primary plastic production value chains, including from the extraction of fossil fuels required for production to shaping the final product. We specifically focus on nine major types of fossil fuel-based plastic polymers that are produced and consumed in large quantities: three types of polyethylene (PE) – low-density (LDPE), linear low-density (LLDPE), and high-density (HDPE) – as well as polypropylene (PP); polyethylene terephthalate (PET); polyvinyl chloride (PVC); polystyrene (PS) and other key styrene-based plastics such as styrene acrylonitrile (SAN) and acrylonitrile butadiene styrene (ABS), and polyurethane (PU). Together these account for about 80% of plastics production.

54 ENVIRONMENTAL SCIENCES↗

Coupling of the Electricity and Transportation Sectors - Part II: Risk Assessment

This comprehensive report explores the intricate interplay through “sector coupling” between the Transportation Sector, Energy Sector, and the critical infrastructure challenges faced by the United States. Aligned with the ambitious federal goal of reducing greenhouse gas emissions, the report analyzes the present vulnerabilities in the fossil fuel supply chain, highlighting instances where the dependence on this industry has been susceptible to local and global disruptions. With a focus on risk assessment, this report establishes a framework to compare the fossil fuel-based transportation sector with the burgeoning electrified sector, considering the evolving technologies in electric vehicles (EVs) and the nascent charging infrastructure. This study delves into the historical reliability of fossil fuel-based transportation and identifies opportunities for strengthening sector coupling between transportation and the electric sector. Assessments of the gasoline-diesel supply chain provide insights into both opportunities and threats, offering a roadmap for creating a more reliable and resilient electrified transportation system. We modeled sectoral coupling scenarios for the current internal combustion engine (ICE)-based and future EV-dominant landscapes, leveraging qualitative sector attributes to identify relative strengths and weaknesses in Part 1 of the report. In this report (Part 2) we continue to understand the role of the electricity sector on transportation and develop a semi-quantitative methodology is employed to evaluate and compare the risks associated with the fossil fueled and electric transportation sector during emergency scenarios, drawing from real-world events like hurricanes and geopolitical disruptions. Different operational scenarios for the fossil fuel and electrified sectors have been developed to understand the risks associated with them. This report concludes with recommendations for the architectural designs of electric charging infrastructure, underlining the need for informed decisions in the transition towards a sustainable and resilient transportation future.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Sorghum: A Multipurpose Bioenergy Crop

Bioethanol and biodiesel produced from renewable energy sources are gaining importance in light of volatile fossil fuel prices, depleting oil reserves, and increasing greenhouse effects associated with the use of fossil fuels. Among several alternative renewable energy sources, energy derived from plant biomass is found to be promising and sustainable. Sorghum [Sorghum bicolor (L.) Moench] is a resilient dryland cereal crop with wide adaptation having high water, nutrient, and radiation use efficiencies. This crop is expected to enhance food, feed, fodder, and fuel security. Sweet sorghum is similar to grain sorghum but has the ability to accumulate sugars in the stalks with- out much reduction in grain production. Hence, it is used as a first-generation biofuel feedstock, where the grain and stalk sugars can be used for producing bioenergy, while energy sorghum or biomass sorghum is increasingly viewed as a potential feedstock for lignocellulosic biofuel production. Although the commercial use of sweet sorghum for bioethanol production has been demonstrated in China and India, the viability of large-scale lignocellulosic conversion of sorghum biomass to biofuels is yet to be demonstrated. Here, this chapter dwells on sorghum feedstock characteristics, biofuel production models, sustainability indicators, and commercialization.

09 BIOMASS FUELS↗

Do Phycosphere associated bacteria affect the growth and lipid production of Phaeodactylum tricornutum Bohlin?

Microalgae biofuels are a promising alternative to fossil fuel energy. However current microalgal biofuel production is inefficient making it more expensive than fossil fuels. To make microalgal biofuels a realistic alternative energy source, improvements are needed in the production of microalgae biomass. Phycosphere-associated bacteria are known to influence microalgae growth and metabolite production. Understanding these interactions could provide new methods for enhancing microalgae biomass and improving the efficiency of producing microalgae biofuels. Co-cultures of Phaeodactylum tricornutum Bohlin and single bacterial species were compared to determine what impact phycosphere-associated bacteria can have on microalgae. Growth rates, total lipid accumulation and fatty acid profiles for each co-culture were compared to an axenic culture of P. tricornutum to assess the impact of the bacterial association. Marinobacter 3-2 significantly increased the lipid accumulation of P. tricornutum during early exponential growth. Two bacterial strains, Algoriphagus ARW1R1 and Muricaud a ARW1Y1, significantly lowered the maximum growth rate and cell densities of P. tricornutum in early and late exponential growth. Lower cell densities in these co-cultures resulted in lower lipid accumulation. Our results suggest that co-culturing P. tricornutum with a phycosphere-associated bacterial species, Marinobacter 3-2, could help improve the efficiency of producing algal biomass and lipids.

59 BASIC BIOLOGICAL SCIENCES↗

An Overview of Policies Influencing Air Pollution from the Electricity Sector in South Asia

The electricity sector is a substantial source of air pollution and associated health problems in South Asia and elsewhere. Fossil-fueled power plants emit a wide variety of harmful pollutants. Those with the greatest health impacts are particulate matter and ozone. Once released into the atmosphere, there is no practical way to remove air pollutants, which means that policies designed to improve air quality have to limit the pollutants before release. However, tackling such pollution is challenging because developing economies also need to provide electricity as a basic necessity for their citizens and as an engine of economic growth. This report provides examples of policies impacting air pollution from the fossil-fuel electricity sector in the South Asian countries of Afghanistan, Bangladesh, Bhutan, India, the Maldives, Nepal, Pakistan, and Sri Lanka. Some of this information was difficult to locate, so this is not a comprehensive study, but rather an overview or "scan" of the sector that includes examples of (1) policies that directly regulate air quality by limiting emissions from specific point sources (by restricting operating hours, for instance), and (2) indirect policies that incentivize or disincentivize polluting activities, such as policies to encourage fuel switching, for example. The report shows (1) the great variation among the policy instruments used in each country, (2) that many countries, especially those that have a mismatch between seasonal demand and resource availability, could improve energy security and reduce air pollution through increased cross-border electricity trade, and (3) some countries have contradictory policies (promoting both coal and renewables, for instance).

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

Tuning Sugarcane Bagasse Biochar into a Potential Carbon Black Substitute for Polyethylene Composites

One of the most used carbonaceous materials by industry are carbon blacks, which have technological applications in polymeric composites, coatings and paints, electric and electrochemical devices. One drawback is that they are produced from fossil fuels. Although biochars are also carbonaceous materials some disadvantages like their larger particles size, high ash content and highly oxygenated surface must be overcome to enable their use as substitute of carbon blacks in composites. Sugarcane bagasse biochar was used to produce carbonaceous materials to substitute carbon blacks. Milling of biochar decreased particle size from several hundreds of micrometers to 100–500 nm and narrowed its size distribution. Chemical leaching reduced the inorganic compounds and ash content by almost 20%. Great advance was achieved when biochar was thermally annealed in alcohol vapor atmosphere which resulted in biochar-based material with very low oxygenated carbon species at particles surface and turned them hydrophobic. Almost no C–O/C=O and O–C=O peaks components were observed at the X-ray photoelectron spectroscopy spectrum. Reactive thermal annealing of the biochar based additive was a key procedure to obtain polyethylene composites (5% loading) with mechanical, thermal and colorimetric properties very close to the ones prepared with the carbon black from fossil fuels.

36 MATERIALS SCIENCE↗

Source Decomposition of Eddy-Covariance CO 2 Flux Measurements for Evaluating a High-Resolution Urban CO 2 Emissions Inventory

We present the comparison of source-partitioned CO2 flux measurements with a high-resolution urban CO 2 emissions inventory (Hestia). Tower-based measurements of CO and 14 C are used to partition net CO 2 flux measurements into fossil and biogenic components. A flux footprint model is used to quantify spatial variation in flux measurements. We compare the daily cycle and spatial structure of Hestia and eddy-covariance derived fossil fuel CO 2 emissions on a seasonal basis. Hestia inventory emissions exceed the eddy-covariance measured emissions by 0.36 µ mol m −2 s −1 (3.2%) in the cold season and 0.62 µ mol m −2 s −1 (9.1%) in the warm season. The daily cycle of fluxes in both products matches closely, with correlations in the hourly mean fluxes of 0.86 (cold season) and 0.93 (warm season). The spatially averaged fluxes also agree in each season and a persistent spatial pattern in the differences during both seasons that may suggest a bias related to residential heating emissions. In addition, in the cold season, the magnitudes of average daytime biological uptake and nighttime respiration at this flux site are approximately 15% and 27% of the mean fossil fuel CO 2 emissions over the same time period, contradicting common assumptions of no significant biological CO 2 exchange in northern cities during winter. This work demonstrates the effectiveness of using trace gas ratios to adapt eddy-covariance flux measurements in urban environments for disaggregating anthropogenic CO 2 emissions and urban ecosystem fluxes at high spatial and temporal resolution.

eddy-covariance flux measurements↗

A study on tensile properties of Alloy 709 at various temperatures

In recent years, there have been several advancements in energy production from both fossil fuels and the alternate “clean” sources such as nuclear fission. These advancements are fueled by the need for more efficient systems that will optimize the use of the depleting fossil fuel reserves and shift the focus to cleaner sources of energy. The efficiency of any power generation cycle is dependent on the ability of the structural material to withstand increased peak operating temperatures. Advanced austenitic stainless steels have been in the focus as structural material for the next generation nuclear power plants, due to their strength, corrosion resistance, weldability and the wide range of temperatures at which the austenite phase is stable. Alloy 709, a recently developed advanced austenitic stainless steel, is being investigated in this paper. Here in this study, tensile tests were conducted on dog-bone samples of Alloy 709 in an in-situ scanning electron microscope (SEM) loading and heating stage, equipped with electron backscatter diffraction (EBSD), at various temperatures. The in-situ experiments indicated that the material primarily accommodated deformation by slip at lower temperatures. Void formation and coalescence at grain boundaries preceded slip at higher temperatures. Although crack initiation at all elevated temperatures was intergranular, the crack propagation through the material and the final fracture was transgranular ductile. Additionally, tensile tests were conducted on larger cylindrical samples at 550, 650 and 750 °C in air. The results of tests conducted in air and in-situ were found to be in agreement, at these temperatures.

36 MATERIALS SCIENCE↗

Impact of solar panels on global climate

Regardless of the harmful effects of burning fossil fuels on global climate1,2, other energy sources will become more important in the future because fossil fuels could run out by the early twenty-second century3 given the present rate of consumption4. This implies that sooner or later humanity will rely heavily on renewable energy sources. Here we model the effects of an idealized large-scale application of renewable energy on global and regional climate relative to a background climate of the representative concentration pathway 2.6 scenario (RCP2.6; ref. 5). We find that solar panels alone induce regional cooling by converting incoming solar energy to electricity in comparison to the climate without solar panels. The conversion of this electricity to heat, primarily in urban areas, increases regional and global temperatures which compensate the cooling effect. However, there are consequences involved with these processes that modulate the global atmospheric circulation, resulting in changes in regional precipitation.

Environmental Sciences & Ecology↗