As with many aspects of sustainability, the terminology originates in accounting. Net zero is no different: the Merriam-Webster dictionary defines ‘net’ as “free from all deductions…excluding all nonessential considerations…as in the net result, net effect” 
‘Net zero emissions’ then does not just mean no new greenhouse gas emissions entering the world’s atmosphere as a result of human activity. Even after we have worked out how to reduce our emissions to zero, other greenhouse gas emissions will continue to enter the atmosphere. These must be balanced by the fact that an amount equivalent to the emissions will be absorbed – whether by human or natural means – from the atmosphere . The net result is zero greenhouse emissions in the atmosphere.
Net zero emissions can be thought of as referring to the balance between the production of greenhouse gas emissions and the amount removed from the atmosphere. Edie defines net zero in its own report as “achieving an overall balance between emission produced and emissions taken out of the atmosphere of the earth”.  To achieve net zero greenhouse gas emissions, the production of emissions must be reduced at the same time as they are actively removed. Net zero greenhouse emissions can also be considered as the ultimate target or goal needed to mitigate the impacts of climate change mitigation.
The main focus of efforts to reduce climate change should be through limiting emissions of carbon dioxide, which is considered the most important greenhouse gas.  Sometimes a net zero target is expressed in terms of greenhouse gas emissions overall, sometimes of carbon dioxide only. The UK Climate Change Act now expresses its net zero emissions target by 2050 in terms of greenhouse gases overall.  Where emissions cannot be eliminated, net zero proposes the need to balance carbon emitted with international offsets or ‘negative emissions’. However, the ‘net’ in ‘net zero; should not give cover for shifting the burden to other countries or future generations. 
Origins: Copenhagen aftermath and the Paris Agreement
The concept of achieving a balance between the production of greenhouse gas emissions and their removal by 2050 originates in the Paris Agreement on climate change. The text of the Agreement states that the world should aim ‘… to achieve a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of this century.’ 
The Paris Agreement also called for nations to adopt “… emission pathways consistent with holding the increase in the global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 °C.” And the Intergovernmental Panel on Climate Change (IPCC) released a report in October 2018 on the 1.5ºC target: it concluded that global emissions need to reach net zero around mid-century to give a reasonable chance of limiting warming to 1.5ºC. 
But the ultimate origin of the concept of net zero can be traced back to a meeting in 2013, at the home of green financier Tessa Tennant on the Scottish borders. A group of 30 lawyers, diplomats, financiers and activists including Christiana Figueres, head of the UN climate body, met in advance of the 2015 Paris summit. The meeting was a testing ground for many elements of the Paris Agreement, including the concept of net zero emissions. 
In 2009, talks had failed at COP15, the Copenhagen climate change conference. In the aftermath it was believed that more concrete, practical measures were needed . Taking inspiration from the Montreal Protocol – the treaty to phase out ozone-depleting CFCs – attendees at the meeting in Scotland opted for the simplicity of zero emissions. Net zero means everyone must ultimately get to zero and applies to organizations of all scales and sectors. 
UN chief Antonio Guterres adopted carbon neutrality by 2050 as the benchmark for ambition ahead of his climate summit in September 2019. 
Offsetting and negative emissions
While carbon dioxide emissions can potentially be reduced to zero in many sectors, such as electricity generation and road transport, this will be far harder to achieve in others, such as aviation or agriculture. 
To achieve net zero, an equivalent amount of carbon dioxide will need to be taken out of the atmosphere to offset these emissions, creating negative emissions. Indeed, the IPCC has argued that the 1.5 degrees Celsius target is only feasible with some level of negative emissions . Human beings currently emit around 50 billion tonnes of carbon dioxide a year. It is estimated 11 billion tonnes of carbon dioxide could need to be removed from the atmosphere annually in order to prevent temperatures rising more than 2ºC. 
There are two broad approaches to withdrawing carbon from the atmosphere:
natural climate solutions (NCS) such as tree planting, restoring peat bogs, coastal ecosystems and adopting alternative agricultural methods.
negative emissions technologies (NETs). The two main NETs are bioenergy with carbon capture and storage (BECCS) and direct air capture (DAC) of carbon dioxide from the atmosphere. The UK’s roadmap to net zero relies heavily on BECCS to meet net zero. 
Global net zero emissions commitments
By early 2021, practically every country had signed up to the Paris Agreement on climate change. In all, more than 120 countries have announced plans for net-zero emissions by 2050, including China, Japan, South Korea, South Africa and Canada. 
Countries representing more than 65 per cent of global carbon dioxide emissions and more than 70 per cent of the world economy, had made commitments to carbon neutrality. The European Union, Japan and the Republic of Korea, together with more than 110 other countries, have pledged carbon neutrality by 2050; China says it will do so before 2060. 
In 2019, the UK and France became the first major economies to set net zero emissions targets for 2050 in law.  Six nations including the UK have passed laws formally establishing net zero targets: Sweden, Scotland and the UK by 2045, France, Denmark and New Zealand by 2050. Similar legislation has been proposed in the EU, Spain, Chile and Fiji. In 2019, the UK became the first G7 nation to pass laws committing it to reach net zero emissions.
Many other countries have set targets but not passed binding legislation. Most of these are aiming to achieve net zero by 2050. Norway is aiming for 2030. Bhutan and Suriname are the only two countries with net negative emissions. The EU has indicated it will also set a 2050 goal. 
Since the withdrawal of the US from the Paris Agreement in 2017, momentum has been decreased. European decision-making and perspectives have come to the fore in terms of influencing countries such as China and India. 
In June 2019, parliament amended the Climate Change Act to require the government to reduce the UK’s net emissions of greenhouse gases by 100% relative to 1990 levels by 2050, taking the UK to net zero emissions. Prior to June 2019, the UK had committed to reducing net greenhouse gas emissions by at least 80% of their 1990 levels.
The Climate Change Act 2008 requires the government to set five-yearly carbon budgets. These run until 2032. The budgets are fixed in advance and set five-year caps on the total greenhouse gas emissions allowed to ensure the UK meets its emissions reductions commitments. The UK is on track to meet its third carbon budget (the current one, covering 2018–22) but is not on track to meet its fourth (2023–27) and fifth (2028–32). 
The sixth carbon budget (2033–37) will be the first to take the UK’s net zero target into account. However, the carbon budgets currently exclude emissions from international aviation and shipping (those produced by planes and ships while in UK territorial waters and airspace). The Committee on Climate Change has advised the UK government to include these emissions in the final net zero target. 
In June 2019, French lawmakers passed legislation setting goals for France to cut its greenhouse gas emissions and go carbon-neutral by 2050 in line with the 2015 Paris climate agreement. The adoption of the law placed France among the first countries to adopt concrete measures to go carbon neutral. Ref 13 The law raises France’s target of reducing consumption of fossil fuels by 40% by 2030 compared with a 30% target cut from 2019. The bill aimed to cut energy consumption from around 7.2 million badly insulated homes. The legislation enables the government to force France’s remaining four coal-fired power plants to close by 2022. 
The Maldives has set a target date for net zero emissions of 2030. The small, low-lying island state is already the brunt of increased storm surges and coastal erosion, thought by many to be the result of the warming climate. 
Norway was among the first parliaments in the world to discuss climate neutrality, with lawmakers agreeing to aim for 2050 domestically and 2030 with international offsets Ref 8. However, this is not a binding climate law. The commitment is also dependent on other countries committing to emissions cuts. If these do not materialise, Norway aims to reach net zero by 2050. Hydropower provides most of Norway’s energy requirements. Transport and oil and gas extraction and processing are its main sources of emissions. It is expected that offsetting with emissions reductions abroad will form the bulk of the country’s net zero efforts. Ref 7 Norway has been accused of having a “superficially radical target of 2030 to achieve carbon neutrality” because of its reliance on investment in carbon-cutting projects overseas. Meanwhile the country continues to extract and export oil. 
Uruguay has forecast it will reach net zero emissions by 2030. This is possible because the country’s forest cover is increasing. Uruguay is one of the few countries in South America whose endemic forests have expanded rather than declined in size. In the 1990s they occupied 660,000 hectares and now they’ve surpassed 850,000 hectares. Ref 9 Meanwhile steps are being taken to reduce emissions from beef farming, waste and energy. Uruguay could be a net carbon sink by 2030, according to its national submission to the UN pact.
In September 2020, China’s president, Xi Jinping announced his company would aim to have CO2 emissions peak before 2030 and achieve carbon neutrality before 2060.Previously, China had said it would peak its emissions by 2030 at the latest, and had avoided committing to a long-term goal.Observers believed that the statement was intended to take advantage of US reluctance to address climate change. 
“China is not a post-industrialised country yet – in fact it will remain the factory of the world for some time. Without underestimating the courage it takes for even industrialised countries to go zero, to do so for China is a challenge at a completely different scale,” says Li Shuo, climate campaigner with Greenpeace East Asia. 
Opposition to net zero
The USA left the Paris climate deal in June 2017. Under president Donald Trump, the US reneged on its existing climate commitments.  US policy is now swinging back in the opposite direction since the election of Joe Biden. In contrast to the Trump administration/ federal level, significant net zero emissions commitments have been made at the US state level (see below).
Climate sceptic Jair Bolsonaro has led resistance to net zero since his election. Even before Bolsonaro’s election, Brazil was among powerful developing companies asking why they should be held to the same timeline as countries that profited from burning fossil fuel for decades before them. 
Other emerging economies are making cautious procedural promises at best, avoiding any commitment to raise ambition. 
There has also been resistance from Poland, the Czech Republic and Hungary. 
India has so far resisted calls for it to make a net zero commitment. Ref 16. India is unlikely to promise net zero any earlier than 2060, too late to help the world meet the under minus 1.5 degree celsius warming target, said Parth Bhatia, senior research associate at Centre for Policy Research (CPR) Initiative on Climate Energy and Environment (ICEE) 
However, Prime Minister Narendra Modi has declared India is going to overperform on its climate commitment of reaching 40% renewable energy in its electricity mix by 2030. 
Meanwhile, some sectors are pushing ahead with net zero commitments. In July 2020, India railways announced plans to achieve net zero emissions by 2030. This follows a target to achieve complete electrification of its network by 2023. 
Net zero is not part of the discourse in Delhi, according to Chandra Bhushan, director of the Centre for Science and Environment. India has aggressive renewable energy and electric vehicle targets, but the imperative to lift people out of poverty sees continuing growth in brown as well as green industries. “With more leadership and global collective action, India will do more,” says Bhushan. “The elephant in the room is Donald Trump. He is going to bring down everyone.” 
Regions and cities
Cities and regions with a carbon footprint greater than the emissions of the US, and companies with a combined revenue of over $11.4 trillion (equivalent to more than half of the US GDP), are now pursuing net zero emissions by the end of the century. 
The majority of these are aiming for net zero emissions by 2050, as part of the UN Race to Zero campaign. This now encompasses 22 regions and 452 cities. 
Carbon reduction targets and net zero commitments are being implemented across the USA in defiance White House denialism. Ref 10 Twenty-three states have committed to GHG reduction targets via legislation or executive order. Several states have enacted economy-wide net zero directives. 
By 2020, four states had committed to completely neutralizing their carbon emissions before 2050 by cutting emissions and investing in carbon capture technology. In June 2018, Hawaii became the first state to commit to net zero carbon emissions statewide .
In Sept. 2018, California committed to a net zero economy by 2045. The California Air Resources Board must collaborate with state agencies to implement reduction measures and track progress. 
In June 2019, New York signed a Climate Leadership and Community Protection Act requiring every sector of the economy to cut GHG emissions 85% from 1990 levels by 2050. The law requires the sequestration of the remaining 15% of state-wide emissions.
In March 2020, Washington also enacted an economy-wide net zero requirement. The 2020 act replaced the state’s existing 57.5% GHG reduction target with a net zero requirement by 2050. Key economic sectors – including electricity, buildings, manufacturing and agriculture – are assigned targets. 
Net Zero Carbon is brought to you by Alfa Energy Group, a leading international energy and sustainability consultancy. Net Zero Carbon provides independent guides, news and insight to organisations and those responsible for the delivery of net zero emissions targets.