Topic: Environment (Page 2)
You are looking at all articles with the topic "Environment". We found 60 matches.
Hint:
To view all topics, click here. Too see the most popular topics, click here instead.
๐ Kardashev Scale
The Kardashev scale is a method of measuring a civilization's level of technological advancement based on the amount of energy they are able to use. The measure was proposed by Soviet astronomer Nikolai Kardashev in 1964. The scale has three designated categories:
- A Typeย I civilization, also called a planetary civilizationโcan use and store all of the energy available on its planet.
- A Typeย II civilization, also called a stellar civilizationโcan use and control energy at the scale of its stellar system.
- A Typeย III civilization, also called a galactic civilizationโcan control energy at the scale of its entire host galaxy.
Discussed on
- "Kardashev Scale" | 2024-05-11 | 34 Upvotes 28 Comments
- "Kardashev Scale" | 2021-10-13 | 14 Upvotes 1 Comments
- "Kardashev Scale" | 2019-08-03 | 74 Upvotes 31 Comments
- "Kardashev scale" | 2011-02-05 | 72 Upvotes 15 Comments
๐ Cancer Alley
Cancer Alley (French: Allรฉe du Cancer) is the regional nickname given to an 85-mile (137ย km) stretch of land along the Mississippi River between Baton Rouge and New Orleans, in the River Parishes of Louisiana, which contains over 200 petrochemical plants and refineries. This area accounts for 25% of the petrochemical production in the United States. Environmentalists consider the region a sacrifice zone where rates of cancer caused by air pollution exceed the federal government's own limits of acceptable risk. Others have referred to the same region as "Death Alley".
Community leaders such as Sharon Lavigne have led the charge in protesting the expansion of the petrochemical industry in Cancer Alley, as well as addressing the associated racial and economic disparities.
Discussed on
- "Cancer Alley" | 2024-01-17 | 181 Upvotes 87 Comments
๐ Holocene Extinction
The Holocene extinction, otherwise referred to as the sixth mass extinction or Anthropocene extinction, is an ongoing extinction event of species during the present Holocene epoch (with the more recent time sometimes called Anthropocene) as a result of human activity. The included extinctions span numerous families of plants and animals, including mammals, birds, amphibians, reptiles and arthropods. With widespread degradation of highly biodiverse habitats such as coral reefs and rainforests, as well as other areas, the vast majority of these extinctions are thought to be undocumented, as the species are undiscovered at the time of their extinction, or no one has yet discovered their extinction. The current rate of extinction of species is estimated at 100 to 1,000 times higher than natural background rates.
The Holocene extinction includes the disappearance of large land animals known as megafauna, starting at the end of the last glacial period. Megafauna outside of the African mainland (thus excluding Madagascar), which did not evolve alongside humans, proved highly sensitive to the introduction of new predation, and many died out shortly after early humans began spreading and hunting across the Earth (many African species have also gone extinct in the Holocene, but โ with few exceptions โ megafauna of the mainland was largely unaffected until a few hundred years ago). These extinctions, occurring near the PleistoceneโHolocene boundary, are sometimes referred to as the Quaternary extinction event.
The most popular theory is that human overhunting of species added to existing stress conditions as the extinction coincides with human emergence. Although there is debate regarding how much human predation affected their decline, certain population declines have been directly correlated with human activity, such as the extinction events of New Zealand and Hawaii. Aside from humans, climate change may have been a driving factor in the megafaunal extinctions, especially at the end of the Pleistocene.
Ecologically, humanity has been noted as an unprecedented "global superpredator" that consistently preys on the adults of other apex predators, and has worldwide effects on food webs. There have been extinctions of species on every land mass and in every ocean: there are many famous examples within Africa, Asia, Europe, Australia, North and South America, and on smaller islands. Overall, the Holocene extinction can be linked to the human impact on the environment. The Holocene extinction continues into the 21st century, with meat consumption, overfishing, and ocean acidification and the decline in amphibian populations being a few broader examples of a cosmopolitan decline in biodiversity. Human population growth and increasing per capita consumption are considered to be the primary drivers of this decline.
The 2019 Global Assessment Report on Biodiversity and Ecosystem Services, published by the United Nations' Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, posits that roughly one million species of plants and animals face extinction within decades as the result of human actions.
Discussed on
- "Holocene Extinction" | 2020-05-08 | 119 Upvotes 124 Comments
๐ Kessler Syndrome
The Kessler syndrome (also called the Kessler effect, collisional cascading, or ablation cascade), proposed by NASA scientist Donald J. Kessler in 1978, is a theoretical scenario in which the density of objects in low Earth orbit (LEO) due to space pollution is high enough that collisions between objects could cause a cascade in which each collision generates space debris that increases the likelihood of further collisions. One implication is that the distribution of debris in orbit could render space activities and the use of satellites in specific orbital ranges difficult for many generations.
Discussed on
- "Kessler Syndrome" | 2020-02-13 | 57 Upvotes 57 Comments
- "Kessler Syndrome" | 2018-11-01 | 63 Upvotes 62 Comments
๐ Spaceship Earth
Spaceship Earth (or Spacecraft Earth or Spaceship Planet Earth) is a worldview encouraging everyone on Earth to act as a harmonious crew working toward the greater good.
Discussed on
- "Spaceship Earth" | 2021-03-14 | 127 Upvotes 95 Comments
- "Spaceship Earth" | 2020-08-23 | 11 Upvotes 3 Comments
๐ Pumped-storage hydroelectricity
Pumped-storage hydroelectricity (PSH), or pumped hydroelectric energy storage (PHES), is a type of hydroelectric energy storage used by electric power systems for load balancing. The method stores energy in the form of gravitational potential energy of water, pumped from a lower elevation reservoir to a higher elevation. Low-cost surplus off-peak electric power is typically used to run the pumps. During periods of high electrical demand, the stored water is released through turbines to produce electric power.
Pumped-storage hydroelectricity allows energy from intermittent sources (such as solar, wind) and other renewables, or excess electricity from continuous base-load sources (such as coal or nuclear) to be saved for periods of higher demand. The reservoirs used with pumped storage can be quite small when contrasted with the lakes of conventional hydroelectric plants of similar power capacity, and generating periods are often less than half a day.
The round-trip efficiency of PSH generally varies between 70%โ80%. Although the losses of the pumping process make the plant a net consumer of energy overall, the system increases revenue by selling more electricity during periods of peak demand, when electricity prices are highest. If the upper lake collects significant rainfall or is fed by a river then the plant may be a net energy producer in the manner of a traditional hydroelectric plant.
Pumped storage is by far the largest-capacity form of grid energy storage available, and, as of 2020, PSH accounts for around 95% of all active storage installations worldwide, with a total installed throughput capacity of over 181ย GW and a total installed storage capacity of over 1.6ย TWh.
The main requirement for PSH is hilly country. The global greenfield pumped hydro atlas lists more than 600,000 potential sites around the world, which is about 100 times more than needed to support 100% renewable electricity. Most are closed-loop systems away from rivers. Areas of natural beauty and new dams on rivers can be avoided because of the very large number of potential sites. Some projects utilise existing reservoirs (dubbed "bluefield") such as the 350 Gigawatt-hour Snowy 2.0 scheme under construction in Australia. Some recently proposed projects propose to take advantage of "brownfield" locations such as disused mines such as the Kidston project under construction in Australia.
Water requirements for PSH are small: about 1 gigalitre of initial fill water per gigawatt-hour of storage. This water is recycled uphill and back downhill between the two reservoirs for many decades, but evaporation losses (beyond what rainfall and any inflow from local waterways provide) must be replaced. Land requirements are also small: about 10 hectares per gigawatt-hour of storage, which is much smaller than the land occupied by the solar and windfarms that the storage might support. Closed loop (off-river) pumped hydro storage has the smallest carbon emissions per unit of storage of all candidates for large-scale energy storage.
Discussed on
- "Pumped-storage hydroelectricity" | 2024-06-30 | 92 Upvotes 130 Comments
๐ Svalbard Global Seed Vault
The Svalbard Global Seed Vault (Norwegian: Svalbard globale frรธhvelv) is a secure seed bank on the Norwegian island of Spitsbergen in the remote Arctic Svalbard archipelago. Conservationist Cary Fowler, in association with the Consultative Group on International Agricultural Research (CGIAR), started the vault to preserve a wide variety of plant seeds that are duplicate samples, or "spare" copies, of seeds held in gene banks worldwide. The seed vault is an attempt to ensure against the loss of seeds in other genebanks during large-scale regional or global crises. The seed vault is managed under terms spelled out in a tripartite agreement among the Norwegian government, the Crop Trust, and the Nordic Genetic Resource Center (NordGen).
The Norwegian government entirely funded the vault's approximately 45 million kr (US$8.8 million in 2008) construction. Storing seeds in the vault is free to end users; Norway and the Crop Trust pay for operational costs. Primary funding for the Trust comes from organisations such as the Bill & Melinda Gates Foundation and from various governments worldwide.
Discussed on
- "Svalbard Global Seed Vault" | 2019-06-13 | 108 Upvotes 13 Comments
- "Svalbard Global Seed Vault" | 2016-05-15 | 63 Upvotes 11 Comments
๐ Azolla Event
The Azolla event is a scenario hypothesized to have occurred in the middle Eocene epoch, around 49ย million years ago, when blooms of the freshwater fern Azolla are thought to have happened in the Arctic Ocean. As they sank to the stagnant sea floor, they were incorporated into the sediment; the resulting draw-down of carbon dioxide has been speculated to have helped transform the planet from a "greenhouse Earth" state, hot enough for turtles and palm trees to prosper at the poles, to the current icehouse Earth known as the Late Cenozoic Ice Age.
Discussed on
- "Azolla Event" | 2019-07-22 | 104 Upvotes 80 Comments
๐ Beaver Drop
The beaver drop was a 1948 Idaho Department of Fish and Game program to relocate beavers (Castor canadensis). The program involved moving 76 beavers by airplane and parachuting them to new areas in Central Idaho. The program was initiated to both reduce cost and decrease mortality rates during the relocation. Alleviating complaints about "nuisance beavers" and their activities were an underlying reason for it.
Discussed on
- "Beaver Drop" | 2024-01-15 | 123 Upvotes 48 Comments
๐ Wicked problem
In planning and policy, a wicked problem is a problem that is difficult or impossible to solve because of incomplete, contradictory, and changing requirements that are often difficult to recognize. It refers to an idea or problem that cannot be fixed, where there is no single solution to the problem; and "wicked" denotes resistance to resolution, rather than evil. Another definition is "a problem whose social complexity means that it has no determinable stopping point". Moreover, because of complex interdependencies, the effort to solve one aspect of a wicked problem may reveal or create other problems.
The phrase was originally used in social planning. Its modern sense was introduced in 1967 by C. West Churchman in a guest editorial Churchman wrote in the journal Management Science, responding to a previous use of the term by Horst Rittel. Churchman discussed the moral responsibility of operations research "to inform the manager in what respect our 'solutions' have failed to tame his wicked problems". Rittel and Melvin M. Webber formally described the concept of wicked problems in a 1973 treatise, contrasting "wicked" problems with relatively "tame", soluble problems in mathematics, chess, or puzzle solving.
Discussed on
- "Wicked problem" | 2020-03-02 | 120 Upvotes 35 Comments