What is Net Zero?

It is international scientific consensus that, in order to prevent the worst climate damages, global net human-caused emissions of carbon dioxide (CO2) need to fall by about 45 percent from 2010 levels by 2030, reaching net zero around 2050. Global warming is proportional to cumulative CO2 emissions, which means that the planet will keep heating for as long as global emissions remain more than zero. This implies that climate damages, caused by global heating, will continue escalating for as long as emissions continue. 

What is net zero?

 

Net zero refers to a state in which the greenhouse gases going into the atmosphere are balanced by removal out of the atmosphere. 

The term net zero is important because – for CO2 at least – this is the state at which global warming stops. The Paris Agreement underlines the need for net zero, requiring states to ‘achieve a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of this century’. 

To ‘go net zero’ is to reduce greenhouse gas emissions and/or to ensure that any ongoing emissions are balanced by removals.

The ‘net’ in net zero is important because it will be very difficult to reduce all emissions to zero on the timescale needed. As well as deep and widespread cuts in emissions, we will likely need to scale up removals. In order for net zero to be effective, it must be permanent, that is, that any greenhouse gas removals do not leak into the atmosphere over time, for example through the destruction of forests or the improper storage of removed carbon dioxide.  

Permanent or hard ‘net zero’ refers to a balance between all greenhouse gas sinks and sources that is sustained over matching time scales.

Net Zero as the Goal 

All of the different terms (Carbon Neutral, Net Zero, Climate Neutral) point to the different ways in which emissions sources and sinks are accounted for in context, and help to indicate what is, and is not included in the calculation or a target. As net zero is the internationally agreed upon goal for mitigating global warming in the second half of the century, and the IPCC concluded the need for net zero CO2 by 2050 to remain consistent with 1.5C – the purpose of this site is to inform effective climate action that is net zero aligned in order to advance progress towards this goal.

Many actors will be able to achieve absolute zero or zero emissions in the process, hence the choice of terms in the global ‘Race to Zero’ campaign focused on raising ambition. Others will need to scale up removals either themselves directly or by supporting other project, hence the ‘net’ in net zero.   

Related Terms

Confusingly, there are several terms related to net zero which have slightly different definitions. We explain them here so as to avoid confusion.

Absolute Zero / Zero Emissions

No GHG emissions are attributable to an actor’s activities across all scopes. Under this definition, no offsets or balancing of residual emissions with removals are used.

A valid end-state target.

Climate Neutral

An actor’s activities result in no net effect on the climate system. Any GHG emissions or other activities with warming effects are fully compensated by GHG reductions or removals, or other activities with cooling effects — irrespective of the time period or the relative magnitude of emissions and removals involved. A near synonym for GHG neutral, but climate neutral also includes non-GHG radiative forcing effects, such as land use changes with albedo effects.

Not a valid end-state target, as it does not require “like for like” balancing, but a possible intermediate step.

GHG Neutral

An actor’s net contribution to global GHG emissions is zero. Any GHG emissions attributable to an actor’s activities are fully compensated by GHG reductions or removals exclusively claimed by the actor — irrespective of the time period or the relative magnitude of emissions and removals involved. 

Not a valid end-state target, as it does not require “like for like” balancing, but a possible intermediate step.

Carbon Neutral

An actor’s net contribution to global CO2 emissions is zero. Any CO2 emissions attributable to an actor’s activities are fully compensated by CO2 reductions or removals exclusively claimed by the actor — irrespective of the time period or the relative magnitude of emissions and removals involved. 

Not a valid end-state target, as it only refers to carbon, but a possible intermediate step.

Climate Positive / Net Negative

An actor’s GHG removals, internal and external, exceed its emissions and any removals are “like for like”. Must be specified over a declared time period, and whether removals and emissions are cumulative or represent only the time period specified.

A valid end-state target.

Carbon Negative

An actor’s carbon removals, internal and external, exceed its emissions and any removals are “like for like”. Must be specified over a declared time period, and whether removals and emissions are cumulative or represent only the time period specified.

Not a valid end-state target, as it only refers to carbon, but a possible intermediate step.

1.5°C Aligned

Target is aligned with scenarios that yield a long-term warming outcome of below 1.5°C with some probability (e.g. 50%, 66%) and some amount of overshoot (e.g. no, low), both of which should be explicitly specified. 

Science-Based / Paris-Aligned

Target is aligned with what the latest climate science deems necessary to meet the goals of the Paris Agreement — limiting global warming to well-below 2°C above preindustrial levels and pursuing efforts to limit warming to 1.5°C, with no or low overshoot.

Offsetting

Reducing GHG emissions (including through avoided emissions), or increasing GHG removals through activities external to an actor, in order to compensate for GHG emissions, such that an actor’s net contribution to global emissions is reduced. Offsetting is typically arranged through a marketplace for carbon credits or other exchange mechanism. 

Offsetting claims are only valid under a rigorous set of conditions, including that the reductions/removals involved are additional, not over-estimated, and exclusively claimed. Further, offsetting can only be used to claim net zero status to the extent it is “like for like” with any residual emissions. 

Insetting

Reducing GHG emissions (including through avoided emissions), or increasing GHG removals through an actor’s scope 1, 2, or 3 emissions, in order to compensate for GHG emissions, such that an actor’s net contribution to global emissions is reduced. 

Insetting claims are only valid under a rigorous set of conditions, including that the reductions/removals involved are additional, not overestimated, and exclusively claimed. Further, insetting can only be used to claim net zero status to the extent it is “like for like” with any residual emissions. 

Neutralization

GHG removals outside an actor’s emissions inventory, that balance residual GHG emissions such that an actor’s net contribution to global emissions is reduced or eliminated. May include offsetting, but also all other activities an actor makes outside its value chain that are contributions to mitigation. Near synonym of compensation, but limited to removals, and requires “like for like” balancing of residual emissions. Required if residual emissions remain after net zero status is achieved. 

Neutralization claims are only valid under a rigorous set of conditions, including that the reductions/removals involved are additional, not over-estimated, exclusively claimed, and “like for like”. 

Neutralization

Compensation

Reducing GHG emissions (including through avoided emissions), or increasing GHG removals through activities outside of an actor’s emissions inventory, in order to compensate for GHG emissions such that an actor’s net contribution to global emissions is reduced. Includes offsetting, but also all other activities an actor makes outside its value chain that are contributions to mitigation. Near synonym of neutralization, but not limited to removals, and does not necessarily imply “like for like” balancing of residual emissions. Potentially helpful during the transition to net zero.

Compensation claims are only valid under a rigorous set of conditions, including that the reductions/removals involved are additional, not over-estimated, and exclusively claimed.

Like for Like

When a source of emissions and an emissions sink correspond in terms of their warming impact, and in terms of the timescale and durability of carbon storage. 

For example, fossil carbon is stable in the lithosphere over millennia if it is not extracted and burned, therefore mitigating measures (e.g. offsets) that aim to neutralise the effect of these emissions must persist for a comparable, geological-timescale. Although all CO2 once emitted, whether originally sourced from the lithosphere or biosphere, persists in the active carbon cycle for centuries to millennia, it may be appropriate to balance shorter-duration carbon released from biogenic carbon stocks (e.g. forests and soils) with comparably temporary storage in like stocks. The variable risks of reversal of different carbon stocks must also be considered, for example forests may suffer from unforeseen anthropogenic (e.g. illegal logging), non-anthropogenic (e.g. disease and disaster), or climate change-induced (e.g. warming) reversal risks.

GHG Reductions

Actions that reduce the quantity of GHGs attributable to an actor vis-a-vis a baseline. 

Examples include: Replacing fossil-burning power with renewable energy, reducing consumption of emissions-intensive products or inputs, avoiding damage to ecological carbon sinks, carbon capture and storage (CCS), avoided emissions from deployment of renewable energy, etc. 

GHG Removals

Actions that remove GHGs from the atmosphere relative to baseline. 

Examples include: Afforestation and reforestation, soil carbon enhancement, bioenergy with carbon capture and storage (BECCS), direct air capture, mineralization, or enhanced weathering. 

In addition to the above definitions, sometimes the aim is not to account for all emissions, just carbon dioxide (CO2), leading to iterations on the above definitions such as net zero carbon, zero carbon and carbon negative.

What does it mean to set a net zero aligned target?

Scope

The scope of net zero refers not only to which greenhouse gases are included, but also which activities are covered.

Generally, net zero refers to all greenhouse gases, that is, all gases covered under the Kyoto Protocol, unless the definition refers to a specific gas (e.g. net zero carbon).

In terms of activity coverage, most national and sub-national actors have a standardised approach to scoping net zero, following the IPCC’s guidelines for calculating national greenhouse gas inventories, bounded geographically (emissions that occur within a given territory).

Within the private sector there are differences, but generally emissions are bounded following the Greenhouse Gas Protocol’s ‘scoped’ approach, and net zero aligned actors should attempt to cover all three scopes. The three scopes cover: 

● Scope 1 – direct company owned or controlled emissions occurring at source

● Scope 2 – emissions associated with the production of energy consumed by a company

● Scope 3 – indirect emissions associated with company activities from sources not owned or controlled by a company.

Timing

While there are differing views about ambition in terms of timing for achieving net zero, there is strong international agreement across the climate community and convenors of the Race to Zero campaign that net zero targets should:

● Reach net zero by 2050

● Set interim targets

● Act immediately

Offsetting

A carbon offset broadly refers to a reduction in GHG emissions – or an increase in carbon storage (e.g., through land restoration or the planting of trees) – that is used to compensate for emissions that occur elsewhere.

While there is disagreement about the widespread use of offsetting there is strong international agreement across the climate community that any offsetting to achieve net requires:

● Robust standards (e.g. additionality, permanence, verifiability, etc.)

● Specification of offsetting approach, avoided emissions, reductions, or removals.

The Oxford Principles for Net Zero Aligned offsetting also require offsetting strategies to:

● Shift from carbon reduction to carbon removal.

● Shift from carbon removal with high-risk (shorter-term) storage, to carbon removal with low-risk (longer-term) storage.

● Support the development of net zero-aligned offsetting.

Equity

There are many equity considerations involved in setting a target to align with the global goal of achieving net zero and there is variation in agreement on how to operationalise differentiation around equity considerations, but there tends to be wide agreement in the international climate community that:

● All should move to net zero, but scope and timing may differ due to capacity, responsibility, and other factors.

Governance

There are key governance considerations for setting net zero strategies. While actor-specific best practices may vary, it is of wide agreement in the climate community that strong governance towards net zero targets will include:

 Formal, top-level commitment

● Interim targets

● Transparency through regular reporting and tracking

● Clear action plans with specific operational implications

Why do we need net zero?

We need to reach net zero emissions in order to achieve the ambition of the Paris Agreement, which is to hold global average temperature increase to “well below 2°C above pre industrial levels and pursuing efforts to limit the temperature increase to 1.5°C”.  The IPCC’s Special Report Global Warming of 1.5°C makes it clear that it is necessary to achieve a global balance between emissions and removals by 2050 in order to cap the rise in global temperatures below 1.5°C

While the Paris Agreement sets a global objective, action to achieve that objective is driven at the national level – each country is responsible for setting their own policies to achieve the common goal. The delivery of these policies will take place at the local level. All countries, cities and businesses need to develop plans as to how they intend to achieve net zero.

While there may be different approaches to achieving net zero, it is important that such plans follow a common set of principles

 

An image of a wind farm.

News and Events

Coldplay to use Oxford Offsetting Principles for unavoidable tour emissions
Coldplay to use Oxford Offsetting Principles for unavoidable tour emissions

Global British band Coldplay have pledged to drawdown any unavoidable emissions of their upcoming tour according to the Oxford Principles for Net-Zero Aligned Carbon Offsetting. Coldplay said: “We pledge to make our upcoming Music Of The ... Read more

UK Net Zero Strategy: Oxford Net Zero academics respond
UK Net Zero Strategy: Oxford Net Zero academics respond

The government has today (19 October) released its Net Zero Strategy, setting out policies and proposals for decarbonising all sectors of the UK economy to meet the UK’s net zero target by 2050. Our academic experts at Oxford Net Zero have been ... Read more

CO2 removal is essential to achieving net zero
CO2 removal is essential to achieving net zero

By Dr Steve Smith, originally published by University of Oxford news on 23 September 2021. Photo: Climeworks. The Orca plant in Iceland. Dr Steve Smith is executive director of the Oxford Net Zero Initiative and the CO2RE hub, which is focussed ... Read more

Oxford Net Zero to Co-host a Climate Neutrality Forum: Register Your Interest
Oxford Net Zero to Co-host a Climate Neutrality Forum: Register Your Interest

Bringing together leading researchers, policymakers and practitioners working on achieving climate neutrality, the meeting will take place simultaneously at four hubs – Berlin, Milan, Brussels and Oxford – linked together to create a blended ... Read more

Getting net zero right, a tool kit.
Getting net zero right, a tool kit.

The term ‘net zero’ and the practical application of the frame for individual entities has been subject to fierce debate and contention in the last weeks and months. The science is clear that we must get our world to a state of net ... Read more

Climate change: what G7 leaders could have said – but didn’t
Climate change: what G7 leaders could have said – but didn’t

By Myles Allen. Originally published on The Conversation, 15 June 2021. Featured image: /Getty The four-day G7 summit in Cornwall ended with little cause for celebration from anyone worried about climate change. Most of the pledges that emerged ... Read more

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What the Hale is @NetZeroTracker + how will it help in the goal to limit global temperature rise to 1.5C?

Here to answer @PaulOutrageAnd's questions is @ThomasNHale as part of our #RaceToZero series. Tune in: http://outrageandoptimism.org

@ECIU_UK @DataDrivenLab @NewClimateInst

“Remarkably, net zero has now gone fully mainstream, but not all pledges are created
equal. The @NetZeroTracker will shine a light on which ones are genuinely ambitious, comprehensive, transparent & accountable," says @thomasnhale

Discover:
https://www.zerotracker.net/

Couldn't be more stoked to get the @NetZeroTracker out the door. Been a hectic few days but a hugely rewarding few months.

https://www.zerotracker.net/ — Until the job's done. Intent to integrity. Quantity, and quality.

The tagline's a work in progress... 🧵 @frankjotzo

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