Carbon neutrality

Carbon neutrality, zero carbon, zero net carbon, zero net carbon emissions, etc, are a series of related ideas about how nations or the Earth as a whole should act to eliminate the production of greenhouse gases and halt anthropogenic global warming.

While halting global warming would certainly be a good thing to do for the survival of Earth's people and animals, it is nonetheless the subject of a lot of nonsense, claim and counter-claim. Politicians are fond of claiming they will achieve carbon neutrality at some time in the future, specified vaguely and far enough away that they'll be long out of office. Some environmentalists want to put all the responsibility onto the government and/or big business, implying that individual people won't have to make any sacrifices and the government should sort it all. Meanwhile many people see a powerful interest in saying, "No, don't try, it can't be done!"

In reality, for a first-world nation to achieve some form of carbon neutrality is likely to require major changes to the operation of government and to individuals' daily lives. This has been debated to some extent in the developed world, with various proposals for green new deals and similar schemes to drastically reduce emissions. But it is far less clear how it can be achieved in the developing world particularly if they are to achieve a western standard of living.

The main sources of greenhouse gases include transport, heating, air conditioning, lighting, industry and manufacturing, construction (e.g. concrete), agriculture, and deforestation. All or most of these will have to change. Other sources such as people breathing and their corpses decomposing will probably have to remain.

Definitions

 * Carbon in these contexts refers to any gas contributing to the greenhouse effect. carbon dioxide is the most prominent, but others such as methane play a significant role.
 * Zero carbon emissions taken literally would mean nothing produces any carbon dioxide or other greenhouse gases.
 * Net zero emissions allows you to offset CO2 production with other actions which absorb CO2 and remove it from the atmosphere, such as planting trees. This is considerably more practical than the previous. The idea of carbon offset has become a dirty word because many schemes are more or less cons (pay me carbon offset money to build something I was going to build anyway) but some mediations are genuine.
 * Offshoring or outsourcing emissions refers to the fact that developed countries import many of their goods, often from less-developed countries, and greenhouse gases are emitted at the point of production as well as at point of use. At an extreme, if the US imported all its electricity from coal or oil generators in Canada, it could claim to have produced no emissions in the US, but will nonetheless be responsible for a large amount of world emissions. This also applies to other fields like the ones in which cows grow. If emissions are offshored rather than reduced, the effect on the Earth is minimal (and probably worse than if they stayed at home — due to greenhouse gas emissions due to transportation).

There are also various exclusions in various schemes, often for things like air travel and shipping, which you could claim is international and therefore shouldn't be included in any one nation's total, although inability to attribute blame is no comfort if your house is sinking between the waves.

Transport
Transport is perhaps what everybody thinks of when it comes to carbon emissions. Air travel is bad, and there is no obvious mediation other than flying much less — high speed rail can replace short-haul flights. Proposals for rationing flights have been advanced. These range from one free return flight for everybody per year, with high tax on additional flights, to proposals for tradeable individual carbon credits.

Internal combustion engine (ICE) cars can be replaced by electric cars. Electric trains, buses, and trams can replace diesel or gasoline public transport. For short journeys, people can walk and cycle. Banning the sale of ICE vehicles is the subject of many vague targets and pious government hopes.

In some cases journeys can be easily replaced with electric public transport, walking, or cycling. But not all. This is a problem for rural dwellers and the disabled, amongst other groups: electric cars and taxicabs are a partial solution, but may not be easily affordable particularly in comparison with motoring today. It may be more efficient for everybody to live in cities, and for the elderly or disabled to live with their families. Since people won't be able to travel around the world to visit relatives, the effect on family life will not be negligible.

Drastically reducing commuting is another possibility, via home working, e-learning, etc. People working in jobs involving transport, deliveries, etc, may find themselves unemployed and hence producing much lower emissions.

Power generation
Power generation is another area where a lot of work has been done. Do you want nuclear power with its risks of pollution (e.g., nuclear waste), wind power with its ugly wind turbines and intermittent production, tidal power with its environmental impact, or lovely clean solar?

Agriculture
Sorry, veganism all round! Cattle farmers are trying to find cattle feed that makes their cows fart less. But realistically meat consumption will have to fall, especially if we're to find lots of land to plant forests on to absorb all our CO2.

Heating
People will have to heat their homes with electricity (possibly augmented by district heating schemes, solar, or geothermal for some) rather than gas, oil, coal, wood, or other fuels. This will reduce air pollution significantly (heavy oil and solid fuels including wood being the worst culprits), but will require vast modifications to large numbers of homes. Energy conservation measures (insulation etc) and zero-carbon building techniques will help but again will require major modifications to a nation's existing housing stock. (And construction potentially produces lots of greenhouse gases, so don't think we can just rebuild everything.)

Consumerism
Things like fast fashion are widely pilloried for their contribution to the greenhouse effect. While some of this is probably misogynistic "silly women buying frivolous shit", all instances where we buy things we don't need are contributing to environmental damage whether it's clothes, books, DVDs, toys, collectible figurines, vaping paraphernalia, sports equipment, gewgaws, knick-knacks, or whatever else you spend your money on.

Population reduction
In itself this will reduce greenhouse gas emissions, although if each remaining person continues to emit gases only a 100% reduction in population will produce zero emissions.

Geoengineering
Environmentalists such as Greenpeace seem to hate this even more than population reduction (which they're normally quiet on), because it doesn't require people to change their behavior or do anything about evil big corporations (environmentalism being as much a moral crusade as a scientific one). It's also not clear that it would work, or be safe. But who knows?

Targets
Various organisations have proposed different target dates for zero emissions. The Intergovernmental Panel on Climate Change (IPCC) recommends that to limit warming to 1.5°C, we need net-zero global CO2 emissions by 2050, with deep reductions in methane and other gases concurrently. This would still produce significant effects on the climate but is a lot better than 2°C.

The UK government's Committee on Climate Change (CCC) proposed 2050 (replacing a previous government commitment for 80% reduction by 2050); Friends of the Earth and other environmentalist groups have said 2045; the Swedish government has set a binding target of 2045. You should refer to the definitions section above: Sweden's zero emissions target excludes international aviation; and other schemes allow countries to buy carbon credits from overseas.

Other organisations propose a far faster reduction. Extinction Rebellion (XR) wants the UK to cut its emissions to zero by 2025. It isn't clear how this would be possible.

Plans
There is some attempt to work out what the targets will require. Practical proposals require vast changes in how people travel, eat, spend, work, and live their lives, as well as requiring large-scale government action on things like public transport and power generation. Government action will be necessary to change the taxation system to encourage (or, in reality, force) people to travel less, eat less meat (sin taxes), and buy less, according to Prof Sir Ian Boyd.

In the UK, the CCC's proposals for zero emissions by 2050 require "the end of petrol and diesel cars and gas boilers, less meat on plates, quadrupling clean electricity generation and planting an estimated 1.5bn trees. It will require tens of billions of pounds of investment every year, the CCC said – about 1-2% of Britain’s GDP." Reductions in a shorter time limit would require greater per-year spending.

The Centre for Alternative Technology (CAT) claims zero carbon is achievable in the UK. Their plan includes: Inevitably the feasibility of some of these will be contested, as will the cost. And at the same time they recommend personal action including changes in travel, diet, and generally buying less things. CAT admits, "This represents a massive transformation in society, but we believe that – with enough political, social and cultural will – it is possible." They estimate 20 years to install the necessary infrastructure in the UK. This implies no earlier than 2039 at time of writing, but even that will require people to pull their finger out and do something — indeed, do a lot, quickly.
 * reduce heating emissions by 50% by insulation and passive heating
 * reduce travel to get reduction of 78%
 * all energy from renewables, with 50% electricity from wind
 * reduce meat and dairy consumption, cut food waste, and reform agriculture
 * massive reforestation and restoration of peat moors to act as carbon sinks.

Internationalism
Any proposal to counter global warming requires all (or nearly all) countries to control their emissions. While some nations are working seriously at this, others still don't seem to view carbon neutrality as necessary.

Politics
Will capitalism allow greenhouse gas reductions? Do we need to change society first, or at the same time? On the other hand, do we have time, and are communists any more environmentally friendly? Or can free market solutions like carbon trading and semi-capitalist solutions like carbon taxes save the planet? Inaction or insufficient action will also have drastic society-changing effects, and likely far worse than carbon emission reduction plans.