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Phase-out of fossil fuel vehicles

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Phase-out_of_fossil_fuel_vehicles

Phase-out of fossil fuel vehicles means stopping selling and using vehicles which are powered by fossil fuels, such as gasoline (petrol), diesel, kerosene and fuel oil: it is one of the three most important parts of the general fossil fuel phase-out process, the others being the phase-out of fossil fuel power plants for electricity generation and decarbonization of industry.

Many countries and cities around the world have stated they will ban the sale of passenger vehicles (primarily cars and buses) powered by fossil fuels such as petrol, liquefied petroleum gas and diesel at some time in the future. Synonyms for the bans include phrases like "banning gas cars", "banning petrol cars", "the petrol and diesel car ban", or simply "the diesel ban". Another method of phase-out is the use of zero-emission zones in cities.

A few places have set dates for banning other types of vehicles, such as fossil fuelled ships and lorries.

Background

Reasons for banning further sale of fossil fuel vehicles include: reducing health risks from pollution particulates, notably diesel PM10s and other emissions, notably nitrogen oxides; meeting national greenhouse gas, such as CO₂, targets under international agreements such as the Kyoto Protocol and the Paris Agreement; or energy independence. The intent to ban vehicles powered by fossil fuels is attractive to governments as it offers a simpler compliance target, compared with a carbon tax or phase-out of fossil fuels.

A BMW i3 being charged in Amsterdam. Electric cars had a world market share of around 5% in 2021.

The automotive industry is working to introduce electric vehicles to adapt to bans with varying success and it is seen by some in the industry as a possible source of money in a declining market. A 2020 study from Eindhoven University of Technology showed that the manufacturing emissions of batteries of new electric cars are much smaller than what was assumed in the 2017 IVL study (around 75 kg CO₂/kWh) and that the lifespan of lithium batteries is also much longer than previously thought (at least 12 years with a mileage of 15,000 km annually): they are cleaner than internal combustion cars powered by diesel or petrol.

There is some opposition to simply moving from fossil-fuel powered cars to electric cars, as they would still require a large proportion of urban land. On the other hand, there are many types of (electric) vehicles that take up little space, such as (cargo) bicycles and electric motorcycles and scooters. Making cycling and walking over short distances, especially in urban areas, more attractive and feasible with measures such as removing roads and parking spaces and improving cycling infrastructure and footpaths (including pavements), provides a partial alternative to replacing all fossil-fuelled vehicles by electric vehicles. Although there are as yet very few completely carfree cities (such as Venice), several are banning all cars in parts of the city, such as city centers.

Methods

The banning of fossil-fuelled vehicles of a defined scope requires authorities to enact legislation that restricts them in a certain way. Proposed methods include:

A prohibition on further sales or registration of new vehicles powered with specific fuels from a certain date in a certain area. At the date of implementation existing vehicles would remain legal to drive on public highways.
A prohibition on the importation of new vehicles powered with specific fuels from a certain date into a certain area. This is planned in countries such as Denmark, Israel and Switzerland; However, some countries, such as Israel, have no legislation on the subject.
A prohibition on any use of certain vehicles powered with specific fuels from a certain date within a certain area. Restrictions such as these are already in place in many European cities, usually in the context of their low-emission zones (LEZs).
Making emission legislation so strict that it can in reality not be fulfilled.

Fuel cell (electric) vehicles (FCVs or FCEVs) also allow running on (some) non-fossil fuels (i.e., hydrogen, ethanol, methanol, ...).

Cities generally use the introduction of low-emission zones (LEZs) or zero-emission zones (ZEZs), sometimes with an accompanying air quality certificate sticker such as Crit'air (France), in order to restrict the use of fossil-fuelled cars in some or all of its territory. These zones are growing in number, size and strictness. Some city bans in countries such as Italy, Germany and Switzerland are only temporarily activated during particular times of the day, during winter, or when there is a smog alert (for example, in Italy in January 2020); these do not directly contribute to the phase-out of fossil fuel vehicles, but they make owning and using such vehicles less attractive as their utility is restricted and the cost of driving them increases.

Some countries have given consumers various incentives such as subsidies or tax breaks in order to stimulate the purchase of electric vehicles, while fossil-fuelled vehicles are taxed increasingly heavily.

Helped by government incentives, Norway became the first country to have the majority of new vehicles sold in 2021 be electric. In January 2022, 88 percent of new vehicles sold in the country were electric, and based upon current trends, they would most likely hit the goal of no new fossil fuel cars being sold by 2025.

Places with planned fossil-fuel vehicle restrictions

International or supranational

In 2018, Denmark proposed an EU-wide prohibition on petrol and diesel cars, but that turned out to be contrary to EU regulations. In October 2019, Denmark made a proposal for phasing out fossil fuel vehicles on the member state level by 2030 and was supported by 10 other EU member states.

In July 2021, the European Commission proposed a 100% reduction of emissions for new sales of cars and vans as of 2035. On 8 June 2022, the European Parliament voted in favour of the proposal of the European Commission, but agreement with the European Union member states was necessary before a final law could be passed. On 22 June 2022, German Finance Minister Christian Lindner stated that his government would refuse to agree on the ban. But on 29 June 2022, after 16 hours of negotiations, all climate ministers of the 27 EU member states agreed to the commission's proposal (part of the 'Fit for 55' package) to effectively ban the sale of new internal combustion vehicles by 2035 (through '[introducing] a 100% CO₂ emissions reduction target by 2035 for new cars and vans'). Germany backed the 2035 target, asking the Commission whether hybrid vehicles or CO₂-neutral fuels could also comply with the proposal; Frans Timmermans responded that the Commission kept an "open mind", but at the time 'hybrids did not deliver sufficient emissions cuts and alternative fuels were prohibitively expensive.'

Countries

Countries with proposed bans or implementing 100% sales of zero-emissions vehicles include China (including Hong Kong and Macau), Japan, Singapore, the UK, South Korea, Iceland, Denmark, Sweden, Norway, Slovenia, Germany, Italy, France, Belgium, the Netherlands, Portugal, Canada, the 12 U.S. states that adhered to California's Zero-Emission Vehicle (ZEV) Program, Sri Lanka, Cabo Verde, and Costa Rica.

Map of proposed bans.

2020s

2030s

2040s

2050s

Country	Start year	Status	Scope	Details
Austria	2040	Signatory of the Glasgow Declaration	Emitting	New vehicle sales by 2040 at latest
Azerbaijan	2040	Signatory of the Glasgow Declaration	Emitting	New vehicle sales by 2040 at latest
Belgium	2026 2029	Climate plan	2026: No further tax deductibility of Diesel, petrol employee company cars 2029: (Flanders region) Diesel, petrol	2026: Only for new cars which are provided as compensation to employees 2029: (Flanders region) New car and van sales
Cambodia	2040	Signatory of the Glasgow Declaration	Emitting	New vehicle sales by 2040 at latest
Canada	2035	climate plan	Diesel, petrol, non-electric	New light-duty vehicle sales
Cape Verde	2040	Signatory of the Glasgow Declaration	Emitting	New vehicle sales by 2040 at latest
Chile	2035	Chilean government Green New Deal.	Diesel, petrol	New vehicle sales
China	2035	Government climate plan.	Diesel, petrol	New private vehicle sales and registration.
Costa Rica	2050	Proposed by Costa Rica President Carlos Alvarado as a "roadway" in 2019.	Diesel, petrol	New light vehicle sales
Croatia	2040	Signatory of the Glasgow Declaration	Emitting	New vehicle sales by 2040 at latest
Cyprus	2040	Signatory of the Glasgow Declaration	Emitting	New vehicle sales by 2040 at latest
Denmark	2030–2035		Diesel, petrol	New vehicle sales (2030), new hybrid vehicle sales will continue to be allowed until 2035.
Dominican Republic	2040	Signatory of the Glasgow Declaration	Emitting	New vehicle sales by 2040 at latest
Egypt	2040	Government plan	Diesel, petrol, non-electric	New car sales
El Salvador	2040	Signatory of the Glasgow Declaration	Emitting	New vehicle sales by 2040 at latest
Finland	2040	Signatory of the Glasgow Declaration	Emitting	New vehicle sales by 2040 at latest
Germany	2030	Bundesrat decision	Emitting	New car sales
Ghana	2040	Signatory of the Glasgow Declaration	Emitting	New vehicle sales by 2040 at latest
Greece	2030	Government plan	Emitting, non-electric	New vehicle sales
Hong Kong	2035	Hong Kong Legislature plan, Special Administrative Region of the People's Republic Of China.	Diesel, petrol	New private vehicle sales and registration.
Iceland	2030	climate plan	Cars than run exclusively on Diesel, petrol	New car sales, but with exceptions for regional considerations (areas where it would be difficult to ban petrol or diesel cars)
India	2040	Government pledge	Petrol, diesel	New vehicle sales
Indonesia	2050	Proposed by the Government as a "roadway" in 2021	Diesel, petrol	All motorcycle sales (2040), all car sales (2050)
Ireland	2040	Signatory of the Glasgow Declaration	Emitting	New vehicle sales by 2040 at latest
Israel	2030		Emitting, non-electric	New car sales, newly imported vehicles
Italy	2035	Ministry of ecologic transition directive	Emitting	New private vehicle sales by 2035 New commercial vehicle sales by 2040
Japan	2035	Japanese government plan	cease sales of new Diesel-, petrol-only cars	Diesel and petrol hybrid cars to continue to be sold indefinitely
Kenya	2040	Signatory of the Glasgow Declaration	Emitting	New vehicle sales by 2040 at latest
Lithuania	2040	Signatory of the Glasgow Declaration	Emitting	New vehicle sales by 2040 at latest
Luxembourg	2040	Signatory of the Glasgow Declaration	Emitting	New vehicle sales by 2040 at latest
Macau	2035	Macau Legislature plan, Special Administrative Region of the People's Republic Of China.	Diesel, petrol	New private vehicle sales and registration.
Mexico	2040	Signatory of the Glasgow Declaration	Emitting	New vehicle sales by 2040 at latest
Morocco	2040	Signatory of the Glasgow Declaration	Emitting	New vehicle sales by 2040 at latest
Netherlands	2030	coalition agreement	Diesel, petrol	New passenger car sales. Commercial vehicles to continue to use petrol and diesel until 2040.
New Zealand	2040	Signatory of the Glasgow Declaration	Emitting	New vehicle sales by 2040 at latest
Norway	2025	tax and usage incentives	Diesel, petrol	All new passenger cars. Commercial vehicles to continue to use petrol and diesel until 2035.
Paraguay	2040	Signatory of the Glasgow Declaration	Emitting	New vehicle sales by 2040 at latest
Poland	2040	Signatory of the Glasgow Declaration	Emitting	New vehicle sales by 2040 at latest
Portugal	2035	Government climate plan proposed by the ruling Socialist Party of Portugal.	Diesel, petrol	New car sales
Rwanda	2040	Signatory of the Glasgow Declaration	Emitting	New vehicle sales by 2040 at latest
Singapore	2025 (Diesel-only Cars and Taxis) 2030 (Petrol-only and Diesel-only Vehicles)	February 2021 Climate plan, brought forward ten years earlier since 2020 announcement.	Petrol, Diesel, non-electrified	Sales and Registration of all new Diesel-only Cars and Taxis to cease by 2025, Sales and Registration of all new Diesel-only Commercial Vehicles and Petrol-only Vehicles to cease by 2030. All new vehicles to run on cleaner energy (electric, hybrid, hydrogen fuel cell) from 2030, phase-out of internal combustion engines (from the entire population of motor vehicles) completed by 2040.
Slovenia	2031	emission limit of 50 g/km	Allow Diesel and petrol if emissions < 50 gr/km	New car registration
South Korea	2035	Government climate plan	Petrol, diesel	New vehicle sales.
Spain	2040		ICE	New passenger car sales only. Commercial vehicles and motorcycles to continue to use petrol or diesel.
Sweden	2030	coalition agreement	Diesel, petrol	New car sales
Taiwan	2040	Government Climate plan announced by the Environmental Protection Administration.	Diesel, petrol	All bus and government-owned car use (2030), all motorcycle sales (2035), all car sales (2040)
Thailand	2035	Only proposals of National Electric Vehicle Policy Committee, not yet effective in any way.	Diesel, petrol	New car sales and new car registration.
Turkey	2040	Signatory of the Glasgow Declaration and declaration on lorries and buses	Emitting	New vehicle sales by 2040 at latest
United Kingdom	2030–2035, 2040		Diesel, petrol	New non-electric car sales from 2030, new hybrid car sales from 2035, new CO₂ emitting lorry and bus sales from 2040
United States	2035	Imposed by US President Joe Biden as Executive Order 14057 that mandates all new light duty vehicles in the government fleet are zero emission by 2027, with all new privately-owned light duty vehicles being zero-emission by 2035.	Diesel, petrol, non-electric	Government acquisition of light-duty vehicles (2027) and government acquisition of all vehicle types and new car sales of privately-owned light-duty vehicles (2035). Entire fleet of government-owned vehicles with ICE engines will be phased-out and will be replaced with 100% all-electric vehicles by 2035-2040. All privately-owned light-duty vehicles with ICE engines will be phased-out and replaced with 100% electric vehicles by 2050.
Uruguay	2040	Signatory of the Glasgow Declaration	Emitting	New vehicle sales by 2040 at latest

Some politicians in some countries have made broad announcements but have implemented no legislation and therefore there is no phase-out and no binding legislation. Ireland, for example, had made announcements but ultimately did not ban diesel nor petrol vehicles.

The International Energy Agency predicted in 2021 that 70% of India's new car sales will be fossil powered in 2030, despite earlier government announcements which were discarded in 2018. In November 2021, the Indian government was amongst 30 national governments and six major automakers who pledged to phase out the sale of all new petrol and diesel vehicles by 2040 worldwide, and by 2035 in "leading markets".

As of late 2021, France opposed a ban on combustion-powered cars and in particular of hybrid vehicles.

Cities and territories

Some cities or territories have planned or taken measures to partially or entirely phase out fossil fuel vehicles earlier than their national governments. In some cases, this is achieved through local or regional government initiatives, in other cases through legal challenges brought on by citizens or civil organisations enforcing partial phase-outs based on the right to clean air.

Some cities listed have signed the Fossil Fuel Free Streets Declaration, committing to ban emitting vehicles by 2030, but this does not necessarily have force of law in those jurisdictions. The bans typically apply to a select number of streets in the urban centre of the city where most people live, not to its entire territory. Some cities take a gradual approach to prohibit the most polluting categories of vehicles first, then the next-most polluting, all the way up to a complete ban on all fossil-fuel vehicles; some cities have not yet set a deadline for a complete ban, and/or are waiting for the national government to set such a date.

In California, emissions requirements for automakers to be permitted to sell any vehicles in the state was expected to force 15% of new vehicles offered for sale between 2018 and 2025 to be zero emission. Much cleaner emissions and increased efficiency in petrol engines mean this will be met with just 8% ZEV vehicles. The "Ditching Dirt Diesel" law SB 44 sponsored by Nancy Skinner and adopted on 20 September 2019 requires the California Air Resources Board (CARB) to "create a comprehensive strategy for deploying medium- and heavy-duty vehicles" to make California meet federal ambient air quality standards, and 'establish goals and spur technology advancements for reducing GHG emissions from the medium- and heavy-duty vehicle sectors by 2030 and 2050'. It stops short of directly requiring a phase-out of all diesel vehicles by 2050 (as the original bill did), but it would be the most obvious means of achieving the reduction goals.

In the European Union, Council Directive 96/62/EC on ambient air quality assessment and management and Directive 2008/50/EC on ambient air quality form the legal basis for EU citizens' right to clean air. On 25 July 2008 in the case Dieter Janecek v Freistaat Bayern CURIA, the European Court of Justice ruled that under Directive 96/62/EC citizens have the right to require national authorities to implement a short-term action plan that aims to maintain or achieve compliance to air quality limit values. The ruling of the German Federal Administrative Court in Leipzig of 5 September 2013 significantly strengthened the right of environmental associations and consumer protection organisations to sue local authorities to enforce compliance with air quality limits throughout an entire city. The Administrative Court of Wiesbaden declared on 30 June 2015 that financial or economic aspects were not a valid excuse to refrain from taking measures to ensure that the limit values were observed, the Administrative Court of Düsseldorf ruled on 13 September 2016 that driving bans on certain diesel vehicles were legally possible in order to comply with the limit values as quickly as possible, and on 26 July 2017 the Administrative Court of Stuttgart ordered the state of Baden-Württemberg to consider a year-round ban on diesel-powered vehicles. By mid-February 2018, citizens in the EU member states the Czech Republic, France, Germany, Hungary, Italy, Romania, Slovakia, Spain and the United Kingdom were suing their governments for violating the limit of 40 micrograms per cubic meter of breathable air as stipulated in the Ambient Air Quality Directive.

A landmark ruling by the German Federal Administrative Court in Leipzig on 27 February 2018 declared that the cities of Stuttgart and Düsseldorf were allowed to legally prohibit older, more polluting diesel vehicles from driving in zones worst affected by pollution, rejecting appeals made by German states against the bans imposed by the two cities' local courts. The case was strongly influenced by the ongoing Volkswagen emissions scandal (also known as Dieselgate), which in 2015 revealed that many Volkswagen diesel engines were deceptively tested and marketed as much cleaner than they were. The decision was predicted to set a precedent for other places in the country and in Europe. Indeed, the ruling triggered a wave of dozens of local diesel restrictions, brought about by Environmental Action Germany (DUH) suing city authorities and winning legal challenges across Germany.^[100] While some groups and parties such as the AfD again tried to overturn them, others such as the Greens advocated for a national phaseout of diesel cars by 2030. On 13 December 2018, the European Court of Justice overturned a 2016 European Commission relaxation of car NO_x emission limits to 168 mg/km, which the Court declared illegal. This allowed the cities of Brussels, Madrid and Paris, who had filed the complaint, to proceed with their plans to also reject Euro 6 diesel vehicles from their urban centres, based on the original 80 mg/km limit set by EU law.

City or territory	Country	Ban announced	Ban commences	Scope	Details
Aachen	Germany	2018	2019	Diesel	Older diesel vehicles (2019), unless pollution reduces.
Amsterdam	Netherlands	2019	2030	Diesel, petrol	Euro I–III diesel cars (2020), non-electric buses (2022), pleasure crafts and (light) mopeds (2025), all vehicles (2030).
Antwerp	Belgium	2016	2017–2025	Diesel, lpg, petrol	Euro I–II diesels and 0 petrol/lpg (2017), Euro III diesels and 1 petrol/lpg (2020), Euro IV diesels and 2 petrol/lpg (2025).
Arnhem	Netherlands	2013, 2018	2014–2019	Diesel	Euro I–III diesel trucks (2014), all Euro I–III diesel vehicles (2019)*.
Athens	Greece	2016	2025	Diesel	All vehicles
Auckland	New Zealand	2017	2030	Diesel, petrol	All vehicles, electric buses by 2025
Australian Capital Territory	Australia	2022	2035	Fossil fuels	All new light fossil fuel vehicles from 2035 encompassing passenger cars, motorcycles and small trucks. This policy forms part of the ACT Government's Zero Emissions Vehicles Strategy 2022–30. The Strategy also targets 80-90% of new light vehicles sold by 2030 to be zero-emission models.
Balearic Islands	Spain	2018	2025–2035	Diesel, petrol	All vehicles
Barcelona	Spain	2017	2030	Diesel, petrol	All vehicles, electric buses by 2025
Berlin	Germany	2018	2019	Diesel	Euro I–V diesel vehicles (2019).
Bonn	Germany	2018	2019	Diesel	Older diesel vehicles (2019).
Bristol	United Kingdom	2019	2021	Diesel	All private vehicles (city center from 7 am to 3 pm)
British Columbia	Canada	2018	2025	Diesel, petrol	All vehicles by 2040, 10% ZEVs by 2025
Brussels Region	Belgium	2018	2030–2035	Diesel, petrol	Euro 0–I diesels (2018), Euro II diesels and 0–1 petrols (2019), Euro III diesels (2020), Euro IV diesels (2022), Euro V diesels and Euro 2 petrol (2025), all diesels (2030), all petrol vehicles (2035)
California	United States	2020	2035	Net-emitting vehicles	All passenger vehicles and light-duty trucks.
Cape Town	South Africa	2017	2030	Diesel, petrol	All vehicles, electric buses by 2025
Cologne	Germany	2018	2019	Diesel	Older diesel vehicles (2019).
Connecticut	United States	2022	2035	Non-electric vehicles	New vehicle sales
Copenhagen	Denmark	2017	2030	Diesel, petrol	All vehicles, electric buses by 2025
Darmstadt	Germany	2018	2019	Diesel	Euro I–V diesel vehicles on two streets (2019).
Düsseldorf	Germany	2013	2014	Diesel, petrol	Euro I–III diesel vehicles and Euro 0 petrol vehicles (2014).
Eindhoven	Netherlands	2020	2030	Diesel, petrol	Euro I–III diesel trucks (2007), Euro I–III diesel buses (2021), Euro IV diesel trucks (2022), all Euro IV diesel vehicles (2025), all vehicles (2030).
Essen	Germany	2018	2030	Diesel	Older diesel vehicles.
Frankfurt	Germany	2018	2019	Diesel	Euro I–V diesel vehicles and Euro 1–2 petrol vehicles (2019).
Gelsenkirchen	Germany	2018	2025	Diesel	Older diesel vehicles.
Ghent	Belgium	2016	2020–2028	Diesel, lpg, petrol	Euro I–III diesel and 1 petrol/lpg (2020), Euro IV–V diesel and 2–3 petrol/lpg (2025–28).^[
Hainan	China	2018	2030	Diesel, petrol	All vehicles
Hawaii	United States	2022	2035	Non-electric vehicles	New vehicle sales
Hamburg	Germany	2018	2018	Diesel	Euro I–V diesel vehicles in one street, older diesel trucks in another street (2020).
Heidelberg	Germany	2017	2030	Diesel, petrol	All vehicles, electric buses by 2025
Lausanne	Switzerland	2021	2030	Thermic vehicles	Zero mobility-related direct emissions
Lombardy	Italy	2018	2019–2020	Diesel, petrol	Euro I–III diesel and Euro 1 petrol (1 April 2019), Euro IV diesel (1 October 2020).
London	United Kingdom	2017	2020–2030	Diesel, petrol	All vehicles, electric buses by 2025 (two zero emissions zones by 2022)
Los Angeles	United States	2017	2030	Diesel, petrol	All vehicles, electric buses by 2025
Madrid	Spain	2016	2025	Diesel	Euro I–III diesel and Euro 1–2 petrol vehicles (2018), all vehicles (2025).
Maine	United States	2022	2035	Non-electric vehicles	New vehicle sales
Massachusetts	United States	2020	2035	Diesel, petrol	Will set equivalent regulations to match California's Advanced Clean Cars Program
Mainz	Germany	2018	2019	Diesel, petrol	Euro I–III diesel vehicles and Euro 0 petrol vehicles (2019).
Mexico City	Mexico	2016	2025	Diesel	All vehicles
Milan	Italy	2017	2030	Diesel	All diesel vehicles, electric buses by 2025
Moscow	Russia	2012, 2019	2013–2021	Non-electric	Euro I–IV bus purchases (2013), all non-electric bus purchases (2021), Euro I–III vehicles (20??), all non-electric vehicles (20??).
Munich	Germany	2011	2012	Diesel, petrol	Euro I–III diesel vehicles and Euro 0 petrol vehicles (2012).
New Jersey	United States	2022	2035	Non-electric vehicles	New vehicle sales
New Mexico	United States	2022	2035	Non-electric vehicles	New vehicle sales
New York State	United States	2021	2035	Non-ZEV vehicles	New passenger cars and trucks and off-road vehicles and equipment
New York City	United States	2020	2040	Non-electric vehicles	All vehicles owned or operated by New York City
Nijmegen	Netherlands	2018	2021	Diesel	Euro I–III diesel cars (2021).
North Carolina	United States	2022	2035	Non-electric vehicles	New vehicle sales.
Oregon	United States	2021	2030	All vehicles	Gas cars (2025), gas trucks (2030)
Oslo	Norway	2019	2030	Emitting	City centre fossil-free (2024), entire city fossil-free (2030).
Oxford	United Kingdom	2017	2020–2035	Diesel, petrol	All vehicles (initially during daytime hours on six streets)
Paris	France	2016	2025	Diesel	All vehicles
Quebec	Canada	2020	2035	Diesel, petrol	Ban of new gas-powered vehicle sales by 2035.
Quito	Ecuador	2017	2030	Diesel, petrol	All vehicles, electric buses by 2025
Rhode Island	United States	2022	2035	Non-electric vehicles	New vehicle sales
Rome	Italy	2018	2024	Diesel	All vehicles, only from historical center
Rotterdam	Netherlands	2015	2016	Diesel	Euro I–III diesel trucks (2016). Other bans were dropped in 2019.
Seattle	United States	2017	2030	Diesel, petrol	All vehicles, electric buses by 2025
Stockholm	Sweden	2017	2020–2022	Diesel, petrol	Euro I–IV vehicles (2020), Euro V vehicles (2022) on one street
Stuttgart	Germany	2018	2019–2020	Diesel	Euro I–IV diesel vehicles (2019), Euro V diesel vehicles (2020).
The Hague	Netherlands	2019	2030	Diesel, petrol	Two-stroke mopeds (2020), Euro I–III diesel vehicles (2021), all vehicles (2030).
Utrecht	Netherlands	2013, 2020	2030	Diesel, petrol	Pre-2001 diesel vehicles from 2015, pre-2004 diesels from 2021, pre-2009 (Euro I–IV) diesels from 2025, all vehicles from 2030.
Vancouver	Canada	2017	2030	Diesel, petrol	All vehicles, electric buses by 2025
Washington	United States	2021	2030	Emitting	New car sales (2025), new truck sales (2030)
Wallonia	Belgium	2018	2023–2030	Diesel, petrol	Euro 0–I (2023), Euro II (2024), Euro III (2025), Euro IV (2026), Euro V diesel vehicles (2028), Euro VI diesel vehicles (2030).
Wiesbaden	Germany	2018	2019	Diesel, petrol	Euro I–III diesel vehicles and Euro 0 petrol vehicles (2019).

Manufacturers with planned fossil-fuel vehicle phase-out roadmaps

In 2017, Volvo announced plans to phase out internal combustion-only vehicle production by 2019, after which all new cars manufactured by Volvo will either be fully electric or electric hybrids. In 2020, the Volvo Group with other truck makers including DAF Trucks, Daimler AG, Ford, Iveco, MAN SE, and Scania AB pledged to end diesel truck sales by 2040.

In 2018, Volkswagen Group's strategy chief said "the year 2026 will be the last product start on a combustion engine platform" for its core brand, Volkswagen.

In 2021, General Motors announced plans to go fully electric by 2035. In the same year, the CEO of Jaguar Land Rover, Thierry Bolloré also claimed it would "achieve zero tailpipe emissions by 2036" and that its Jaguar brand would be electric-only by 2025. By March, Volvo Cars announced that by 2030 it "intends to only sell fully electric cars and phase out any car in its global portfolio with an internal combustion engine, including hybrids". In April 2021, Honda announced that it will stop selling gas-powered vehicles by 2040. In July 2021, Mercedes-Benz announced that its new vehicle platforms will be EV-only by 2025. In Oct 2021, Rolls-Royce announced that it will be fully electric by 2030. In November 2021, at 2021 United Nations Climate Change Conference, car manufacturers including BYD Auto, Ford Motor Company, General Motors, Jaguar, Land Rover, Mercedes-Benz and Volvo have committed to "work towards all sales of new cars and vans being zero emission globally by 2040, and by no later than 2035 in leading markets".

In 2022, Maserati announced its plans to offer full-electric variants of all its models by 2025 and its intention to halt production of combustion engine vehicles by 2030.

Railways

While railway electrification is often pursued for reasons unrelated to the emissions caused by fossil fuels, there has been an increased push in the 21st century to replace diesel locomotives with alternatives such as battery electric multiple units, hydrogen fuel trains like the Alstom Coradia iLint or overhead wire electrification. To date the only (non-micro- or city-state) country to have electrified its entire mainline railway network, Switzerland, pursued this phase-out of fossil fuel vehicles before the term or concept existed in the modern form, in large part because importing coal for steam locomotives had proven difficult during the World Wars but Switzerland has plenty of domestic hydropower resources to power electric trains. Israel Railways which had no electrified mainline rail services prior to 2018 when the Tel Aviv-Jerusalem railway became the first line to see electric train operation, plans to electrify most or all of its network and to phase out diesel locomotives and diesel multiple units. The project was further accelerated in 2020 as the temporary shutdown of rail traffic due to the COVID-19 pandemic in Israel allowed faster construction and ERTMS level 2 was being rolled out. However, in 2019 Israel Railways ordered diesel powered rolling stock to replace the aging IC3 trains with media reports citing delays in the electrification program as the main reason.

Shipping

Emissions will be banned from Norway's Geirangerfjord and Nærøyfjord world heritage sites from 2026.

Besides boats driven by batteries or indeed trolley boats, there have been several attempts to adapt nuclear marine propulsion which has been a part of the military naval forces of many countries for decades in the form of nuclear submarines, nuclear aircraft carriers and nuclear icebreakers to civilian uses. While prototypes like Otto Hahn (ship) (German) NS Savannah (American) and RV Mirai (Japan) were built, the only non-icebreaker nuclear powered ship to remain in civilian service is the Russian Sevmorput built in the late 1980s by the Soviet Union. The Soviet Union and its successor state Russia also maintains a fleet of nuclear icebreakers to keep the Northern Sea Route open.

Sail ships and oars rely on renewable resources rather than fossil fuels (wind and human muscle-power respectively) but have disadvantages in terms of speed and labor-costs and have thus been phased out of virtually all commercial uses. There are some attempts to use wind-powered ships for commercial purposes, but as of 2022 they have remained marginal.

Aviation

Norway, and possibly some other Scandinavian countries, are aiming for all domestic flights to be emission-free by 2040. A major obstacle to decarbonizing air travel is the low energy density of current and foreseeable battery technology. Thus alternatives to electric planes such as so called sustainable aviation fuels or e-fuels (fuels derived from electrochemical conversion of substances like water and carbon dioxide into hydrocarbons) are also proposed as a future replacement of current jet fuels. In 2021 the first production scale plant for e-fuels to be used in aviation opened in northern Germany. Production capacity is planned to reach 8 barrels a day by 2022. Lufthansa will be among the chief users of the synthetic fuel produced in the new facility. Germany's plan to transform aviation to net zero carbon emissions relies heavily on e-fuels.

Besides the need to rapidly scale up currently minuscule production capacity, the main obstacles to wider deployment of sustainable aviation fuels and e-Fuels are their much higher cost in the absence of meaningful carbon pricing in aviation. Furthermore, with current CORSIA regulations for sustainable aviation fuels allowing up to 90% of emissions compared to conventional fuels, even those options are currently far from carbon neutral.

There were attempts at building Nuclear-powered aircraft during the Cold War, which unlike nuclear marine propulsion never got very far and were always only proposed for military uses. As of 2022 no country or private enterprise is seriously pursuing nuclear propulsion for passenger aircraft.

However, short haul, low demand routes can be easily flown using electric aircraft, and manufacturers such as Heart Aerospace are planning to introduce them with United Airlines in 2026.

Unintended side-effects

Second-hand vehicle dumping

From the European Union, there is already an export market which includes millions of used cars which are sent to Eastern Europe and the Caucasus, central Asia and Africa. According to UNECE, the global on-road vehicle fleet is to double by 2050 (from 1.2 billion to 2.5 billion, see introduction), with most future car purchases taking place in developing countries. Some experts predict that the number of vehicles in developing countries will increase by 4 or 5-fold by 2050 (compared to current car use levels), and that the majority of these will be second-hand. There are currently no global or even regional agreements that rationalise and govern the flow of second-hand vehicles. Others say that new electric 2-wheelers may sell widely in developing countries as they are affordable.

Internal combustion engine cars that may no longer comply to local environmental standards are exported to developing countries, where legislation on vehicle emissions is often less strict. In addition, in some developing countries, such as Uganda, the average age of a car imported is already 16.5 years and it will likely be driven for another 20 years. In such cases, fuel efficiency levels of these vehicles become worse as they age. In addition, national vehicle inspection requirements vary widely depending on the country.

Potential solutions

Export prohibitions: some proposed that the European Union could implement a rule that does not allow the most polluting cars to leave the EU. The European Union itself is of the opinion that it "should stop exporting its waste outside of the EU" and it will therefore "revisit the rules on waste shipments and illegal exports".
Import prohibitions: include used vehicle bans, used vehicle import age limits, taxation and inspection tests as a precondition to vehicle registration
Convert fossil fuel vehicles to electric: As of 2021 this is expensive so tends only to be done for classic cars.
Mandatory recycling: the European Commission is considering plans to introduce rules on mandatory recycled content in specific product groups, for instance for packaging, vehicles, construction materials and batteries. The EU announced a new Circular Economy Action Plan in March 2020, and it mentioned that "the Commission will also propose to revise the rules on end-of-life vehicles with a view to promoting more circular business models.
Scrappage programs: governments can offer a premium to owners to have their fossil fuelled vehicles voluntarily scrapped, and to buy a cleaner vehicle from that money (if they so choose). For example, the city of Ghent offers a scrapping premium of 1000 euros for diesel vehicles and 750 euros for petrol vehicles; as of December 2019, the city had allocated 1.2 million euros for this purpose to the scrapping fund.

Mobility transition

In Germany, activists have coined the term Verkehrswende (mobility transition, analogous to "Energiewende", energy transition) for a project of not only changing the motive power of cars (from fossil fuels to renewable power sources) but the entire mobility system to one of walkability, complete streets, public transit, electrified railways and bicycle infrastructure.

Community (ecology)

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Community_(ecology)

A bear with a salmon. Interspecific interactions such as predation are a key aspect of community ecology.

In ecology, a community is a group or association of populations of two or more different species occupying the same geographical area at the same time, also known as a biocoenosis, biotic community, biological community, ecological community, or life assemblage. The term community has a variety of uses. In its simplest form it refers to groups of organisms in a specific place or time, for example, "the fish community of Lake Ontario before industrialization".

Community ecology or synecology is the study of the interactions between species in communities on many spatial and temporal scales, including the distribution, structure, abundance, demography, and interactions between coexisting populations. The primary focus of community ecology is on the interactions between populations as determined by specific genotypic and phenotypic characteristics.

Community ecology also takes into account abiotic factors that influence species distributions or interactions (e.g. annual temperature or soil pH). For example, the plant communities inhabiting deserts are very different from those found in tropical rainforests due to differences in annual precipitation. Humans can also affect community structure through habitat disturbance, such as the introduction of invasive species.

On a deeper level the meaning and value of the community concept in ecology is up for debate. Communities have traditionally been understood on a fine scale in terms of local processes constructing (or destructing) an assemblage of species, such as the way climate change is likely to affect the make-up of grass communities. Recently this local community focus has been criticised. Robert Ricklefs has argued that it is more useful to think of communities on a regional scale, drawing on evolutionary taxonomy and biogeography, where some species or clades evolve and others go extinct.

Organisation

Niche

Within the community, each species occupies a niche. A species' niche determines how it interacts with the environment around it and its role within the community. By having different niches species are able to coexist. This is known as niche partitioning. For example, the time of day a species hunts or the prey it hunts.

Niche partitioning reduces competition between species. Such that species are able to coexist as they suppress their own growth more than they limit the growth of other species. The competition within a species is greater than the competition between species. Intraspecific competition is greater than interspecific.

The number of niches present in a community determines the number of species present. If two species have the same niche (e.g., the same food demands) then one species outcompetes the other. The more niches filled, the higher the biodiversity of the community.

Trophic Level

a) A trophic pyramid showing the different trophic levels in a community. b) A food web of the same community

A species’ trophic level is their position in the food chain or web. At the bottom of the food web are autotrophs, also known as primary producer. Producers provide their own energy through photosynthesis or chemosynthesis, plants are primary producers. The next level is herbivores (primary consumers), these species feed on vegetation for their energy source. Herbivores are consumed by omnivores or carnivores. These species are secondary and tertiary consumers. Additional levels to the trophic scale come when smaller omnivores or carnivores are eaten by larger ones. At the top of the food web is the apex predator, this animal species is not consumed by any other in the community. Herbivores, omnivores and carnivores are all heterotrophs.

A basic example of a food chain is; grass → rabbit → fox. Food chains become more complex when more species are present, often being food webs. Energy is passed up through trophic levels. Energy is lost at each level, due to ecological inefficiencies.

The trophic level of an organism can change based on the other species present. For example, tuna can be an apex predator eating the smaller fish, such as mackerel. However, in a community where a shark species is present the shark becomes the apex predator, feeding on the tuna.

Decomposers play a role in the trophic pyramid. They provide energy source and nutrients to the plant species in the community. Decomposers such as fungi and bacteria recycle energy back to the base of the food web by feeding on dead organisms from all trophic levels.

Guild

A guild is a group of species in the community that utilise the same resources in a similar way. Organisms in the same guild experience competition due to their shared resource. Closely related species are often in the same guild, due to traits inherited through common descent from their common ancestor. However, guilds are not exclusively composed of closely related species.

Carnivores, omnivores and herbivores are all basic examples of guilds. A more precise guild would be vertebrates that forage for ground dwelling arthropods, this would contain certain birds and mammals. Flowering plants that have the same pollinator also form a guild.

Influential species

Certain species have a greater influence on the community through their direct and indirect interactions with other species. The loss of these species results in large changes to the community, often reducing the stability of the community. Climate change and the introduction of invasive species can affect the functioning of key species and thus have knock-on effects on the community processes.

Foundation species

Foundation species largely influence the population, dynamics and processes of a community. These species can occupy any trophic level but tend to be producers. Red mangrove is a foundation species in marine communities. The mangrove's root provides nursery grounds for young fish, such as snappers.

Whitebark pine (Pinus albicaulis) is a foundation species. Post fire disturbance the tree provides shade (due to its dense growth) enabling the regrowth of other plant species in the community, This growth prompts the return of invertebrates and microbes needed for decomposition. Whitebark pine seeds provide food for grizzly bears.

A simple trophic cascade diagram. On the right shows when wolves are absent, showing an increase in elks and reduction in vegetation growth. The left one shows when wolves are present and controlling the elk population.

Keystone species

Keystone species have a disproportionate influence on the community than most species. Keystone species tend to be at the higher trophic levels, often being the apex predator. Removal of the keystone species causes top-down trophic cascades. Wolves are keystone species, being an apex predator.

In Yellowstone National Park the loss of the wolf population through overhunting resulted in the loss of biodiversity in the community. The wolves had controlled the number of elks in the park, through predation. Without the wolves the elk population drastically increased, resulting in overgrazing. This negatively affected the other organisms in the park; the increased grazing from the elks removed food sources from other animals present. Wolves have since been reintroduced to return the park community to optimal functioning. See Wolf reintroduction and History of wolves in Yellowstone for more details on this case study.

A marine example of a keystone species is Pisaster ochraceus. This starfish controls the abundance of Mytilus californianus, allowing enough resources for the other species in the community.

Ecological engineers

An ecosystem engineer is a species that maintains, modifies and creates aspects of a community. They cause physical changes to the habitat and alter the resources available to the other organisms present.

Dam building beavers are ecological engineers. Through the cutting of trees to form dams they alter the flow of water in a community. These changes influence the vegetation on the riparian zone, studies show biodiversity is increased. Burrowing by the beavers creates channels, increasing the connections between habitats. This aids the movement of other organisms in the community such as frogs.

Theories of community structure

Community structure is the composition of the community. It is often measured be measured through biological networks, such as food webs.

Holistic theory

Holistic theory refers to the idea that a community is defined by the interactions between the organisms in it. All species are interdependent, each playing a vital role in the working of the community. Due to this communities are repeatable and easy to identify, with similar abiotic factors controlling throughout.

Frederic Clements developed the holistic (or organismic) concept of community, as if it were a superorganism or discrete unit, with sharp boundaries. Clements proposed this theory after noticing that certain plant species were regularly found together in habitats, he concluded that the species were dependent on each other. Formation of communities is non-random and involves coevolution.

The Holistic theory stems from the greater thinking of Holism—which refers to a system with many parts, all required for the system to function.

Individualistic theory

Henry Gleason developed the individualistic (also known as open or continuum) concept of community, with the abundance of a population of a species changing gradually along complex environmental gradients. Each species changes independently in relation to other species present along the gradient. Association of species is random and due to coincidence. Varying environmental conditions and each species' probability of arriving and becoming established along the gradient influence the community composition.

Individualistic theory proposes that communities can exist as continuous entities, in addition to the discrete groups referred to in the holistic theory.

Neutral theory

Stephen P. Hubbell introduced the neutral theory of ecology. Within the community (or metacommunity), species are functionally equivalent, and the abundance of a population of a species changes by stochastic demographic processes (i.e., random births and deaths). Equivalence of the species in the community leads to ecological drift. Ecological drift leads to species' populations randomly fluctuating, whilst the overall number of individuals in the community remains constant. When an individual dies, there is an equal chance of each species colonising that plot. Stochastic changes can cause species within the community to go extinct, however, this can take a long time if there are many individuals of that species.

Species can coexist because they are similar, resources and conditions apply a filter to the type of species that are present in the community. Each population has the same adaptive value (competitive and dispersal abilities) and resources demand. Local and regional composition represent a balance between speciation or dispersal (which increase diversity), and random extinctions (which decrease diversity).

Interspecific interactions

Species interact in various ways: competition, predation, parasitism, mutualism, commensalism, etc. The organization of a biological community with respect to ecological interactions is referred to as community structure.

Interactions		Negative	Neutral	Positive
Interactions		Species 1
Species 2	Negative	Competition	Amensalism	Predation/Parasitism
	Neutral	Amensalism	Neutralism	Commensalism
	Positive	Predation/Parasitism	Commensalism	Mutualism

Competition

Species can compete with each other for finite resources. It is considered an important limiting factor of population size, biomass and species richness. Many types of competition have been described, but proving the existence of these interactions is a matter of debate. Direct competition has been observed between individuals, populations and species, but there is little evidence that competition has been the driving force in the evolution of large groups.

Interference competition: occurs when an individual of one species directly interferes with an individual of another species. This can be for food or for territory. Examples include a lion chasing a hyena from a kill, or a plant releasing allelopathic chemicals to impede the growth of a competing species.
Apparent competition: occurs when two species share a predator. For example, a cougar preys on woodland caribou and deer. The populations of both species can be depressed by predation without direct exploitative competition.

Table visualising size-symmetric competition, using fish as consumers and crabs as resources.

Exploitative competition: This occurs via the consumption of resources. When an individual of one species consumes a resource (e.g., food, shelter, sunlight, etc.), that resource is no longer available for consumption by a member of a second species. Exploitative competition is thought to be more common in nature, but care must be taken to distinguish it from the apparent competition. An example of exploitative competition could be between herbivores consuming vegetation; rabbit and deer both eating meadow grass. Exploitative competition varies:

complete symmetric - all individuals receive the same amount of resources, irrespective of their size
perfect size symmetric - all individuals exploit the same amount of resource per unit biomass
absolute size-asymmetric - the largest individuals exploit all the available resource.

The degree of size asymmetry has major effects on the structure and diversity of ecological communities

Predation

Predation is hunting another species for food. This is a positive-negative interaction, the predator species benefits while the prey species is harmed. Some predators kill their prey before eating them, also known as kill and consume. For example, a hawk catching and killing a mouse. Other predators are parasites that feed on prey while alive, for example, a vampire bat feeding on a cow. Parasitism can however lead to death of the host organism over time. Another example is the feeding on plants of herbivores, for example, a cow grazing. Predation may affect the population size of predators and prey and the number of species coexisting in a community.

Predation can be specialist, for example the least weasel predates solely on the field vole. Or generalist, e.g. polar bear primarily eats seals but can switch diet to birds when seal population is low.

Species can be solitary or group predators. The advantage of hunting in a group means bigger prey can be taken, however, the food source must be shared. Wolves are group predators, whilst tigers are solitary.

A generalised graph of a predator-prey population density cycle

Predation is density dependant, often leading to population cycles. When prey is abundant predator species increases, thus eating more prey species and causing the prey population to decline. Due to lack of food the predator population declines. Due to lack of predation the prey population increases. See Lotka–Volterra equations for more details on this. A well-known example of this is lynx-hare population cycles seen in the north.

Predation can result in coevolution – evolutionary arms race, prey adapts to avoid predator, predator evolves. For example, a prey species develops a toxin that kills its predator and the predator evolves resistance to the toxin making it no longer lethal.

Mutualism

Mutualism is an interaction between species in which both benefit.

An example is Rhizobium bacteria growing in nodules on the roots of legumes. This relationship between plant and bacteria is endosymbiotic, the bacteria living on the roots of the legume. The plant provides compounds made during photosynthesis to the bacteria, that can be used as an energy source. Whilst Rhizobium is a nitrogen fixing bacteria, providing amino acids or ammonium to the plant.

Insects pollinating the flowers of angiosperms, is another example. Many plants are dependent on pollination from a pollinator. A pollinator transfers pollen from the male flower to the female's stigma. This fertilises the flower and enables the plant to reproduce. Bees, such as honeybees, are the most commonly known pollinators. Bees get nectar from the plant that they use as an energy source. Un-transferred pollen provides protein for the bee. The plant benefits through fertilisation, whilst the bee is provided with food.

Commensalism

Commensalism is a type of relationship among organisms in which one organism benefits while the other organism is neither benefited nor harmed. The organism that benefited is called the commensal while the other organism that is neither benefited nor harmed is called the host.

For example, an epiphytic orchid attached to the tree for support benefits the orchid but neither harms nor benefits the tree. This type of commensalism is called inquilinism, the orchid permanently lives on the tree.

Phoresy is another type of commensalism, the commensal uses the host solely for transport. Many mite species rely on another organism, such as birds or mammals, for dispersal.

Metabiosis is the final form of commensalism. The commensal relies on the host to prepare an environment suitable for life. For example, Kelp has a root like system, called a holdfast, that attaches it to the seabed. Once rooted it provides molluscs, such as sea snails, with a home that protects them from predation.

Amensalism

The opposite of commensalism is amensalism, an interspecific relationship in which a product of one organism has a negative effect on another organism but the original organism is unaffected.

An example is an interaction been tadpoles of the common frog and a freshwater snail. The tadpoles consume large amounts of micro-algae. Making algae less abundant for the snail, the algae available for the snail is also of lower quality. The tadpole, therefore, has a negative effect on the snail without a gaining noticeable advantage from the snail. The tadpoles would obtain the same amount of food with or without the presence of the snail.

An older, taller tree can inhibit the growth of smaller trees. A new sapling growing in the shade of a mature tree struggles to get light for photosynthesis. The mature tree also has a well-developed root system, helping it outcompete the sapling for nutrients. Growth of the sapling is therefore impeded, often resulting in death. The relationship between the two trees is amensalism, the mature tree is unaffected by the presence of the smaller one.

Parasitism

Parasitism is an interaction in which one organism, the host, is harmed while the other, the parasite, benefits.

Parasitism is a symbiosis, a long-term bond in which the parasite feeds on the host or takes resources from the host. Parasites can live within the body such as a tapeworm. Or on the body's surface, for example head-lice.

A red-chested cuckoo chick being feed by a significantly smaller Cape robin-chat adult

Malaria is a result of a parasitic relationship between a female Anopheles mosquito and ‘’Plasmodium’’. Mosquitos get the parasite by feeding on an infected vertebrate. Inside the mosquito the plasmodium develops in the midgut's wall. Once developed to a zygote the parasite moves to the salivary glands where it can be passed on to a vertebrate species, for example humans. The mosquito acts as a vector for Malaria. The parasite tends to reduce the mosquito's lifespan and inhibits the production of offspring.

A second example of parasitism is brood parasitism. Cuckoos regularly do this type of parasitism. Cuckoos lay their eggs in the nest of another species of birds. The host, therefore, provides for the cuckoo chick as if it were as their own, unable to tell the difference. The cuckoo chicks eject the host's young from the nest meaning they get a greater level of care and resources from the parents. Rearing for young is costly and can reduce the success of future offspring, thus the cuckoo attempts to avoid this cost through brood parasitism.

In a similar way to predation, parasitism can lead to an evolutionary arms race. The host evolves to protect themselves from the parasite and the parasite evolves to overcome this restriction.

Neutralism

Neutralism is where species interact, but the interaction has no noticeable effects on either species involved. Due to the interconnectedness of communities, true neutralism is rare. Examples of neutralism in ecological systems are hard to prove, due to the indirect effects that species can have on each other.

Material properties of diamond

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Material_properties_of_diamond

Diamond
An octahedral diamond crystal in matrix
General
Category	Native Nonmetal, Mineral
Formula (repeating unit)	Carbon (C)
Crystal system	Diamond cubic (a = 3.56683 Å)
Identification
Color	Most often colorless to yellow or brown. Rarely pink, orange, green, blue, gray, or red.
Crystal habit	Octahedral, cubo-octahedral, spherical or cubic
Cleavage	Perfect; parallel to the octahedral face
Fracture	Irregular
Mohs scale hardness	10
Streak	white
Diaphaneity	Clear to not
Specific gravity	3.516–3.525
Refractive index	2.417
Pleochroism	None
Fusibility	Burns above 700 °C in air.
Solubility	Resistant to acids, but dissolves irreversibly in hot steel
Other characteristics	boiling point = none, very low vapor pressure before decomposing in solid state
Major varieties
Ballas	Spherical, radial structure, cryptocrystalline, opaque black
Bort	Poorly formed, cryptocrystalline, shapeless, translucent
Carbonado	Massive, microcrystalline, opaque black

Diamond is the allotrope of carbon in which the carbon atoms are arranged in the specific type of cubic lattice called diamond cubic. It is a crystal that is transparent to opaque and which is generally isotropic (no or very weak birefringence). Diamond is the hardest naturally occurring material known. Yet, due to important structural brittleness, bulk diamond's toughness is only fair to good. The precise tensile strength of bulk diamond is little known; however, compressive strength up to 60 GPa has been observed, and it could be as high as 90–100 GPa in the form of micro/nanometer-sized wires or needles (~100–300 nm in diameter, micrometers long), with a corresponding maximum tensile elastic strain in excess of 9%. The anisotropy of diamond hardness is carefully considered during diamond cutting. Diamond has a high refractive index (2.417) and moderate dispersion (0.044) properties that give cut diamonds their brilliance. Scientists classify diamonds into four main types according to the nature of crystallographic defects present. Trace impurities substitutionally replacing carbon atoms in a diamond's crystal structure, and in some cases structural defects, are responsible for the wide range of colors seen in diamond. Most diamonds are electrical insulators and extremely efficient thermal conductors. Unlike many other minerals, the specific gravity of diamond crystals (3.52) has rather small variation from diamond to diamond.

Hardness and crystal structure

Known to the ancient Greeks as ἀδάμας (adámas, 'proper, unalterable, unbreakable') and sometimes called adamant, diamond is the hardest known naturally occurring material, and serves as the definition of 10 on the Mohs scale of mineral hardness. Diamond is extremely strong owing to its crystal structure, known as diamond cubic, in which each carbon atom has four neighbors covalently bonded to it. Bulk cubic boron nitride (c-BN) is nearly as hard as diamond. Diamond reacts with some materials, such as steel, and c-BN wears less when cutting or abrading them. (Its zincblende structure is like the diamond cubic structure, but with alternating types of atoms.) A currently hypothetical material, beta carbon nitride (β-C₃N₄), may also be as hard or harder in one form. It has been shown that some diamond aggregates having nanometer grain size are harder and tougher than conventional large diamond crystals, thus they perform better as abrasive material. Owing to the use of those new ultra-hard materials for diamond testing, more accurate values are now known for diamond hardness. A surface perpendicular to the [111] crystallographic direction (that is the longest diagonal of a cube) of a pure (i.e., type IIa) diamond has a hardness value of 167 GPa when scratched with a nanodiamond tip, while the nanodiamond sample itself has a value of 310 GPa when tested with another nanodiamond tip. Because the test only works properly with a tip made of harder material than the sample being tested, the true value for nanodiamond is likely somewhat lower than 310 GPa.

Visualisation of a diamond cubic unit cell: 1. Components of a unit cell, 2. One unit cell, 3. A lattice of 3×3×3 unit cells

Molar volume vs. pressure at room temperature.

3D ball-and-stick model of a diamond lattice

The precise tensile strength of diamond is unknown, though strength up to 60 GPa has been observed, and theoretically it could be as high as 90–225 GPa depending on the sample volume/size, the perfection of diamond lattice and on its orientation: Tensile strength is the highest for the [100] crystal direction (normal to the cubic face), smaller for the [110] and the smallest for the [111] axis (along the longest cube diagonal). Diamond also has one of the smallest compressibilities of any material.

Cubic diamonds have a perfect and easy octahedral cleavage, which means that they only have four planes—weak directions following the faces of the octahedron where there are fewer bonds—along which diamond can easily split upon blunt impact to leave a smooth surface. Similarly, diamond's hardness is markedly directional: the hardest direction is the diagonal on the cube face, 100 times harder than the softest direction, which is the dodecahedral plane. The octahedral plane is intermediate between the two extremes. The diamond cutting process relies heavily on this directional hardness, as without it a diamond would be nearly impossible to fashion. Cleavage also plays a helpful role, especially in large stones where the cutter wishes to remove flawed material or to produce more than one stone from the same piece of rough (e.g. Cullinan Diamond).

Diamonds crystallize in the diamond cubic crystal system (space group Fd3m) and consist of tetrahedrally, covalently bonded carbon atoms. A second form called lonsdaleite, with hexagonal symmetry, has also been found, but it is extremely rare and forms only in meteorites or in laboratory synthesis. The local environment of each atom is identical in the two structures. From theoretical considerations, lonsdaleite is expected to be harder than diamond, but the size and quality of the available stones are insufficient to test this hypothesis. In terms of crystal habit, diamonds occur most often as euhedral (well-formed) or rounded octahedra and twinned, flattened octahedra with a triangular outline. Other forms include dodecahedra and (rarely) cubes. There is evidence that nitrogen impurities play an important role in the formation of well-shaped euhedral crystals. The largest diamonds found, such as the Cullinan Diamond, were shapeless. These diamonds are pure (i.e. type II) and therefore contain little if any nitrogen.

The faces of diamond octahedrons are highly lustrous owing to their hardness; triangular shaped growth defects (trigons) or etch pits are often present on the faces. A diamond's fracture is irregular. Diamonds which are nearly round, due to the formation of multiple steps on octahedral faces, are commonly coated in a gum-like skin (nyf). The combination of stepped faces, growth defects, and nyf produces a "scaly" or corrugated appearance. Many diamonds are so distorted that few crystal faces are discernible. Some diamonds found in Brazil and the Democratic Republic of the Congo are polycrystalline and occur as opaque, darkly colored, spherical, radial masses of tiny crystals; these are known as ballas and are important to industry as they lack the cleavage planes of single-crystal diamond. Carbonado is a similar opaque microcrystalline form which occurs in shapeless masses. Like ballas diamond, carbonado lacks cleavage planes and its specific gravity varies widely from 2.9 to 3.5. Bort diamonds, found in Brazil, Venezuela, and Guyana, are the most common type of industrial-grade diamond. They are also polycrystalline and often poorly crystallized; they are translucent and cleave easily.

Because of its great hardness and strong molecular bonding, a cut diamond's facets and facet edges appear the flattest and sharpest. A curious side effect of diamond's surface perfection is hydrophobia combined with lipophilia. The former property means a drop of water placed on a diamond will form a coherent droplet, whereas in most other minerals the water would spread out to cover the surface. Similarly, diamond is unusually lipophilic, meaning grease and oil readily collect on a diamond's surface. Whereas on other minerals oil would form coherent drops, on a diamond the oil would spread. This property is exploited in the use of so-called "grease pens," which apply a line of grease to the surface of a suspect diamond simulant. Diamond surfaces are hydrophobic when the surface carbon atoms terminate with a hydrogen atom and hydrophilic when the surface atoms terminate with an oxygen atom or hydroxyl radical. Treatment with gases or plasmas containing the appropriate gas, at temperatures of 450 °C or higher, can change the surface property completely.^[9] Naturally occurring diamonds have a surface with less than a half monolayer coverage of oxygen, the balance being hydrogen and the behavior is moderately hydrophobic. This allows for separation from other minerals at the mine using the so-called "grease-belt".

Toughness

Diamonds in an angle grinder blade

Unlike hardness, which denotes only resistance to scratching, diamond's toughness or tenacity is only fair to good. Toughness relates to the ability to resist breakage from falls or impacts. Because of diamond's perfect and easy cleavage, it is vulnerable to breakage. A diamond will shatter if hit with an ordinary hammer. The toughness of natural diamond has been measured as 2.0 MPa⋅m^1/2, which is good compared to other gemstones like aquamarine (blue colored), but poor compared to most engineering materials. As with any material, the macroscopic geometry of a diamond contributes to its resistance to breakage. Diamond has a cleavage plane and is therefore more fragile in some orientations than others. Diamond cutters use this attribute to cleave some stones, prior to faceting.

Ballas and carbonado diamond are exceptional, as they are polycrystalline and therefore much tougher than single-crystal diamond; they are used for deep-drilling bits and other demanding industrial applications. Particular faceting shapes of diamonds are more prone to breakage and thus may be uninsurable by reputable insurance companies. The brilliant cut of gemstones is designed specifically to reduce the likelihood of breakage or splintering.

Solid foreign crystals are commonly present in diamond. They are mostly minerals, such as olivine, garnets, ruby, and many others. These and other inclusions, such as internal fractures or "feathers", can compromise the structural integrity of a diamond. Cut diamonds that have been enhanced to improve their clarity via glass infilling of fractures or cavities are especially fragile, as the glass will not stand up to ultrasonic cleaning or the rigors of the jeweler's torch. Fracture-filled diamonds may shatter if treated improperly.

Pressure resistance

Used in so-called diamond anvil experiments to create high-pressure environments, diamonds are able to withstand crushing pressures in excess of 600 gigapascals (6 million atmospheres).

Optical properties

Color and its causes

Synthetic diamonds of various colors grown by the high-pressure high-temperature technique, the diamond size is ~2 mm

Pure diamonds, before and after irradiation and annealing. Clockwise from left bottom: 1) initial (2 mm × 2 mm); 2–4) irradiated by different doses of 2 MeV electrons; 5–6) irradiated by different doses and annealed at 800 °C.

Diamonds occur in various colors: black, brown, yellow, gray, white, blue, orange, purple to pink and red. Colored diamonds contain crystallographic defects, including substitutional impurities and structural defects, that cause the coloration. Theoretically, pure diamonds would be transparent and colorless. Diamonds are scientifically classed into two main types and several subtypes, according to the nature of defects present and how they affect light absorption:

Type I diamond has nitrogen (N) atoms as the main impurity, at a concentration of up to 1%. If the N atoms are in pairs or larger aggregates, they do not affect the diamond's color; these are Type Ia. About 98% of gem diamonds are type Ia: these diamonds belong to the Cape series, named after the diamond-rich region formerly known as Cape Province in South Africa, whose deposits are largely Type Ia. If the nitrogen atoms are dispersed throughout the crystal in isolated sites (not paired or grouped), they give the stone an intense yellow or occasionally brown tint (type Ib); the rare canary diamonds belong to this type, which represents only ~0.1% of known natural diamonds. Synthetic diamond containing nitrogen is usually of type Ib. Type Ia and Ib diamonds absorb in both the infrared and ultraviolet region of the electromagnetic spectrum, from 320 nm. They also have a characteristic fluorescence and visible absorption spectrum (see Optical properties).

Type II diamonds have very few if any nitrogen impurities. Pure (type IIa) diamond can be colored pink, red, or brown owing to structural anomalies arising through plastic deformation during crystal growth; these diamonds are rare (1.8% of gem diamonds), but constitute a large percentage of Australian diamonds. Type IIb diamonds, which account for ~0.1% of gem diamonds, are usually a steely blue or gray due to boron atoms scattered within the crystal matrix. These diamonds are also semiconductors, unlike other diamond types (see Electrical properties). Most blue-gray diamonds coming from the Argyle mine of Australia are not of type IIb, but of Ia type. Those diamonds contain large concentrations of defects and impurities (especially hydrogen and nitrogen) and the origin of their color is yet uncertain. Type II diamonds weakly absorb in a different region of the infrared (the absorption is due to the diamond lattice rather than impurities), and transmit in the ultraviolet below 225 nm, unlike type I diamonds. They also have differing fluorescence characteristics, but no discernible visible absorption spectrum.

Certain diamond enhancement techniques are commonly used to artificially produce an array of colors, including blue, green, yellow, red, and black. Color enhancement techniques usually involve irradiation, including proton bombardment via cyclotrons; neutron bombardment in the piles of nuclear reactors; and electron bombardment by Van de Graaff generators. These high-energy particles physically alter the diamond's crystal lattice, knocking carbon atoms out of place and producing color centers. The depth of color penetration depends on the technique and its duration, and in some cases the diamond may be left radioactive to some degree.

Some irradiated diamonds are completely natural; one famous example is the Dresden Green Diamond. In these natural stones the color is imparted by "radiation burns" (natural irradiation by alpha particles originating from uranium ore) in the form of small patches, usually only micrometers deep. Additionally, Type IIa diamonds can have their structural deformations "repaired" via a high-pressure high-temperature (HPHT) process, removing much or all of the diamond's color.

Luster

A scattering of round-brilliant cut diamonds shows the many reflecting facets

The luster of a diamond is described as 'adamantine', which simply means diamond-like. Reflections on a properly cut diamond's facets are undistorted, due to their flatness. The refractive index of diamond (as measured via sodium light, 589.3 nm) is 2.417. Because it is cubic in structure, diamond is also isotropic. Its high dispersion of 0.044 (variation of refractive index across the visible spectrum) manifests in the perceptible fire of cut diamonds. This fire—flashes of prismatic colors seen in transparent stones—is perhaps diamond's most important optical property from a jewelry perspective. The prominence or amount of fire seen in a stone is heavily influenced by the choice of diamond cut and its associated proportions (particularly crown height), although the body color of fancy (i.e., unusual) diamonds may hide their fire to some degree.

More than 20 other minerals have higher dispersion (that is difference in refractive index for blue and red light) than diamond, such as titanite 0.051, andradite 0.057, cassiterite 0.071, strontium titanate 0.109, sphalerite 0.156, synthetic rutile 0.330, cinnabar 0.4, etc. (see dispersion). However, the combination of dispersion with extreme hardness, wear and chemical resistivity, as well as clever marketing, determines the exceptional value of diamond as a gemstone.

Fluorescence

A photograph (top) and UV-excited photoluminescence image (bottom) from a plate cut from a synthetic diamond (width ~3 mm). Most of yellow color and green emission originate from nickel impurities.

Diamonds exhibit fluorescence, that is, they emit light of various colors and intensities under long-wave ultraviolet light (365 nm): Cape series stones (type Ia) usually fluoresce blue, and these stones may also phosphoresce yellow, a unique property among gemstones. Other possible long-wave fluorescence colors are green (usually in brown stones), yellow, mauve, or red (in type IIb diamonds). In natural diamonds, there is typically little if any response to short-wave ultraviolet, but the reverse is true of synthetic diamonds. Some natural type IIb diamonds phosphoresce blue after exposure to short-wave ultraviolet. In natural diamonds, fluorescence under X-rays is generally bluish-white, yellowish or greenish. Some diamonds, particularly Canadian diamonds, show no fluorescence.

The origin of the luminescence colors is often unclear and not unique. Blue emission from type IIa and IIb diamonds is reliably identified with dislocations by directly correlating the emission with dislocations in an electron microscope. However, blue emission in type Ia diamond could be either due to dislocations or the N3 defects (three nitrogen atoms bordering a vacancy). Green emission in natural diamond is usually due to the H3 center (two substitutional nitrogen atoms separated by a vacancy), whereas in synthetic diamond it usually originates from nickel used as a catalyst (see figure). Orange or red emission could be due to various reasons, one being the nitrogen-vacancy center which is present in sufficient quantities in all types of diamond, even type IIb.

Optical absorption

Cape series (Ia) diamonds have a visible absorption spectrum (as seen through a direct-vision spectroscope) consisting of a fine line in the violet at 415.5 nm; however, this line is often invisible until the diamond has been cooled to very low temperatures. Associated with this are weaker lines at 478 nm, 465 nm, 452 nm, 435 nm, and 423 nm. All those lines are labeled as N3 and N2 optical centers and associated with a defect consisting of three nitrogen atoms bordering a vacancy. Other stones show additional bands: brown, green, or yellow diamonds show a band in the green at 504 nm (H3 center, see above), sometimes accompanied by two additional weak bands at 537 nm and 495 nm (H4 center, a large complex presumably involving 4 substitutional nitrogen atoms and 2 lattice vacancies). Type IIb diamonds may absorb in the far red due to the substitutional boron, but otherwise show no observable visible absorption spectrum.

Gemological laboratories make use of spectrophotometer machines that can distinguish natural, artificial, and color-enhanced diamonds. The spectrophotometers analyze the infrared, visible, and ultraviolet absorption and luminescence spectra of diamonds cooled with liquid nitrogen to detect tell-tale absorption lines that are not normally discernible.

Electrical properties

Diamond is a good electrical insulator, having a resistivity of 100 GΩ⋅m to 1 EΩ⋅m (10×10¹¹ – 10×10¹⁸ Ω⋅m). Most natural blue diamonds are an exception and are semiconductors due to substitutional boron impurities replacing carbon atoms. Natural blue or blue-gray diamonds, common for the Argyle diamond mine in Australia, are rich in hydrogen; these diamonds are not semiconductors and it is unclear whether hydrogen is actually responsible for their blue-gray color. Natural blue diamonds containing boron and synthetic diamonds doped with boron are p-type semiconductors. N-type diamond films are reproducibly synthesized by phosphorus doping during chemical vapor deposition. Diode p-n junctions and UV light emitting diodes (LEDs, at 235 nm) have been produced by sequential deposition of p-type (boron-doped) and n-type (phosphorus-doped) layers. Diamond's electronic properties can be also modulated by strain engineering.

Diamond transistors have been produced (for research purposes). FETs with SiN dielectric layers, and SC-FETs have been made.

In April 2004, the journal Nature reported that below the superconducting transition temperature 4 K, boron-doped diamond synthesized at high temperature and high pressure is a bulk superconductor. Superconductivity was later observed in heavily boron-doped films grown by various chemical vapor deposition techniques, and the highest reported transition temperature (by 2009) is 11.4 K. (See also Covalent superconductor#Diamond)

Uncommon magnetic properties (spin glass state) were observed in diamond nanocrystals intercalated with potassium. Unlike paramagnetic host material, magnetic susceptibility measurements of intercalated nanodiamond revealed distinct ferromagnetic behavior at 5 K. This is essentially different from results of potassium intercalation in graphite or C60 fullerene, and shows that sp3 bonding promotes magnetic ordering in carbon. The measurements presented first experimental evidence of intercalation-induced spin-glass state in a nanocrystalline diamond system.

Thermal conductivity

Unlike most electrical insulators, diamond is a good conductor of heat because of the strong covalent bonding and low phonon scattering. Thermal conductivity of natural diamond was measured to be about 2200 W/(m·K), which is five times more than silver, the most thermally conductive metal. Monocrystalline synthetic diamond enriched to 99.9% the isotope ¹²C had the highest thermal conductivity of any known solid at room temperature: 3320 W/(m·K), though reports exist of superior thermal conductivity in both carbon nanotubes and graphene. Because diamond has such high thermal conductance it is already used in semiconductor manufacture to prevent silicon and other semiconducting materials from overheating. At lower temperatures conductivity becomes even better, and reaches 41000 W/(m·K) at 104 K (¹²C-enriched diamond).

Diamond's high thermal conductivity is used by jewelers and gemologists who may employ an electronic thermal probe to distinguish diamonds from their imitations. These probes consist of a pair of battery-powered thermistors mounted in a fine copper tip. One thermistor functions as a heating device while the other measures the temperature of the copper tip: if the stone being tested is a diamond, it will conduct the tip's thermal energy rapidly enough to produce a measurable temperature drop. This test takes about 2–3 seconds. However, older probes will be fooled by moissanite, a crystalline mineral form of silicon carbide introduced in 1998 as an alternative to diamonds, which has a similar thermal conductivity.

Technologically, the high thermal conductivity of diamond is used for the efficient heat removal in high-end power electronics. Diamond is especially appealing in situations where electrical conductivity of the heat sinking material cannot be tolerated e.g. for the thermal management of high-power radio-frequency (RF) microcoils that are used to produce strong and local RF fields.

Thermal stability

Diamond and graphite are two allotropes of carbon: pure forms of the same element that differ in structure.

Being a form of carbon, diamond oxidizes in air if heated over 700 °C. In absence of oxygen, e.g. in a flow of high-purity argon gas, diamond can be heated up to about 1700 °C. Its surface blackens, but can be recovered by re-polishing. At high pressure (~20 GPa) diamond can be heated up to 2500 °C, and a report published in 2009 suggests that diamond can withstand temperatures of 3000 °C and above.

Diamonds are carbon crystals that form deep within the Earth under high temperatures and extreme pressures. At surface air pressure (one atmosphere), diamonds are not as stable as graphite, and so the decay of diamond is thermodynamically favorable (δH = −2 kJ/mol). So, contrary to De Beers' ad campaign extending from 1948 to at least 2013 under the slogan "A diamond is forever", diamonds are definitely not forever. However, owing to a very large kinetic energy barrier, diamonds are metastable; they will not decay into graphite under normal conditions.

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Wednesday, September 7, 2022

Phase-out of fossil fuel vehicles

Background

Methods

Places with planned fossil-fuel vehicle restrictions

International or supranational

Countries

Cities and territories

Manufacturers with planned fossil-fuel vehicle phase-out roadmaps

Railways

Shipping

Aviation

Unintended side-effects

Second-hand vehicle dumping

Potential solutions

Mobility transition

Community (ecology)

Organisation

Niche

Trophic Level

Guild

Influential species

Foundation species

Keystone species

Ecological engineers

Theories of community structure

Holistic theory

Individualistic theory

Neutral theory

Interspecific interactions

Competition

Predation

Mutualism

Commensalism

Amensalism

Parasitism

Neutralism

Material properties of diamond

Hardness and crystal structure

Toughness

Pressure resistance

Optical properties

Color and its causes

Luster

Fluorescence

Optical absorption

Electrical properties

Thermal conductivity

Thermal stability

Operator (computer programming)