COP26 Universities Network Briefing / march 2021

Destination net zero: setting and delivering ambitious, credible targets

Key messages • Stabilising global temperatures at any level requires reaching net zero emissions. Stabilising at 1.5°C would mean reaching net zero global emissions of CO2 by mid-century and substantial reduction of other greenhouse gas emissions; the Paris Agreement also commits to a balance in human-caused sources and sinks of all greenhouse gases in the second half of the century.

• Net zero means balancing emissions (sources) with removals (sinks), which requires deep and widespread emissions cuts, as well as scaling up both nature-based and technological removal methods.

• Allied to net zero targets, immediate reductions of greenhouse gas emissions are essential, as global temperature rise is driven by cumulative carbon dioxide emissions over time. Reductions in emissions at source (as opposed to offsets and removals) should form the bulk of action to achieve net zero targets.

• Individual net zero targets and the pathways to achieve them should be driven by considerations of responsibility and capacity. To reflect their equity obligations under the Paris Agreement, industrialised nations should, as a matter of best practice, consider setting targets for delivering net zero before 2050.

• In order to be truly comprehensive, net zero targets should include all seven greenhouse gas groups reported under national inventories (while ensuring net zero CO2 specifically) and cover all economic sectors of activity.

• Plans should be specified for how an agreed net zero target will be delivered, and immediate policy action should be taken to put them on track. These plans should be published, as should regular updates on progress towards achieving them.

• An encouraging number of net zero targets are being set by national governments, regional, local and city governments, businesses, universities and third sector organisations. COP26 is an opportunity for more commitments to be made, and for ensuring targets are backed up by plans for delivery.

• Net zero targets and near-term actions to implement them can be expected to produce a range of benefits – as well as co-benefits – to those who adopt them.

1Destination net zero: setting and delivering ambitious, credible targets

IntroductionNet zero emissions targets have gained traction in the global effort to halt climate change1. In 2019, the UK became the first of the G7 nations to make a legally binding commitment to reaching net zero greenhouse gas emissions by 2050. Of the G20, China has recently committed to carbon neutrality by 2060, while South Korea and Japan have committed to net zero emissions by 2050. At least 53% of gross domestic product (GDP) is now produced in countries, regions or cities where net zero emissions targets have either been agreed or are being proposed2.

Setting strong, ambitious targets for achieving net zero emissions enables governments at national, regional and city level to clearly align with the Paris

Agreement. They provide a clear deadline for creating a zero-carbon economy, giving certainty and clarity for planners, industry, investors and consumers. Similarly, businesses and other organisations benefit from setting their own net zero targets by providing accountability to their stakeholders that they are changing their operations at the scale and pace needed for alignment with the Paris Agreement.

As the impacts of the COVID-19 crisis continue to be acutely felt, a net zero emissions transformation can also significantly aid economic recovery. Sustainable recovery policies could, if well designed, create more jobs, deliver higher short-term returns per pound spent and higher long-term cost savings, in comparison to traditional fiscal stimulus.

Briefing authors: | Katrine Petersen, Imperial College London | Myles Allen, University of Oxford | Chris Hilson, University of Reading

| Chris Jones, University of Manchester | David Reay, University of Edinburgh | Steve Smith, University of Oxford

2Destination net zero: setting and delivering ambitious, credible targets

They could also produce clear ‘co-benefits’ in terms of e.g. reduced urban air pollution, which is associated with increased morbidity and mortality rates. All of this makes embedding net zero targets into future economic planning an even more compelling approach3.

However, a net zero target is only as strong as the action to deliver on it. Meeting the Paris Agreement goal by setting a net-zero target is ultimately path dependent, and contingent on short term measures to reduce CO2 emissions sufficiently in line with the global carbon budget4.

This briefing sets out the science behind net zero targets and the considerations that policymakers and industry leaders should take when adopting and implementing such targets to represent the highest ambition in both planning and delivery.

The science of net zeroThe Paris Agreement stipulates a long-term temperature goal to keep global warming to well below 2°C and to pursue efforts to limit it to 1.5°C above pre-industrial levels.

Article 4 of the Agreement states that this must be achieved by reaching a balance between sources and sinks of greenhouse gases from human activities in the second half of this century;a,5 what is commonly known as ‘net zero’ emissions.

The impacts of the current 1°C of global warming – such as on wildfires, heatwaves and flooding – are already playing out across the globe and will become more severe with any increases in global temperature. Aiming for the more ambitious Paris Agreement temperature target – namely 1.5°C above pre-industrial levels – significantly reduces the risks and impacts of further climate change4.

Answering the question of what it will take to achieve this, the Intergovernmental Panel on Climate Change’s (IPCC) 2018 Special Report on the impacts of 1.5°C of global warming showed that global emissions must reach their peak immediately and then fall rapidly over the following decades. CO2 emissions dominate the climate impact from human activities and have a cumulative effect on temperature, so they must reach net zero for global temperatures to stabilise at any given level. To limit warming to 1.5°C, this will need to happen by 2050. Other greenhouse gas emissions will need to be reduced substantially by this point as well and continue to fall thereafter, with the IPCC calculating that net zero greenhouse gas emissions will need to be achieved around 2065.

Importantly, targeting net zero emissions does not negate the need for substantial efforts on adaptation and resilience-building measures. Even if the world achieves net zero emissions, global temperature will

continue to rise up to that point, and sea levels will continue to rise for many years beyond7.

The ‘net’ in net zero targetsThe emphasis on ‘net zero’, rather than simply ‘zero’ – i.e. ending greenhouse gas emissions fully at the source – stems from the difficulty of achieving the latter by 2050.

Even if all measures to reduce greenhouse gas emissions are rolled out immediately, it is likely that some emissions will remain difficult to phase out completely, such as those from some industrial activities, agriculture and aviation sectors. In a net zero emissions future, any residual emissions would be balanced by removals from the atmosphere through technological and nature-based solutions8.

However, there are significant uncertainties in large-scale removal of greenhouse gases. Technological solutions such as Direct Air Carbon Capture and Storage (DACCS), a process in which carbon dioxide is chemically trapped from the air, concentrated, and piped to geological stores, are still expensive and are still untested for large-scale use.

For nature-based solutions, relying on tree planting to reach net zero targets would require large amounts of land, posing risks for biodiversity and food production9. In addition, there are issues of long-term sustainability of using biosphere carbon storage to offset fossil fuel carbon emissions, as explained in Box 1.

Box 1: Net zero carbon emissions and ‘carbon neutrality’ Stopping CO2 emissions from causing global warming is a minimum requirement for halting total human-induced warming. This requires a global balance between CO2 emissions and CO2 removal (i.e. ‘net zero’ CO2 emissions); also known as ‘carbon neutrality’. This balance must be sustainable, permanent and resilient to climate change.

Current approaches to achieving net zero CO2 often rely on balancing out fossil-fuel emissions with offsetting through biosphere carbon storage (such as through afforestation). However, such large-scale conversion between fundamentally different carbon reservoirs may not be sustainable over multi-decadal timescales, particularly should global warming itself cause carbon stored in the biosphere to be re-emitted to the atmosphere6. As such, reaching ‘sustainable and permanent net zero’ will require changes to future offsetting and removal strategies, including ensuring they are resilient to current and future impacts of climate change.

a How natural and human-caused fluxes are disentangled is still a point of discussion.

3Destination net zero: setting and delivering ambitious, credible targets

As such, any net zero target must ultimately involve a targeted plan to bring emissions down as much as possible in absolute terms, across all economic sectors, alongside innovating and testing technologies both for removal and for hard-to-treat emissions.

Net zero might now also be considered the minimum target that is acceptable for industrialised countries, given their larger historical emissions and current contribution to climate change, as well as greater capability to tackle current emissions. Crucially, the UK’s 2050 target is for ‘at least’ net zero greenhouse gas emissions, while Sweden, for example, is looking to achieve negative net greenhouse gas emissions after reaching its 2045 net zero target.

Setting an achievable and equitable target dateWhile deciding to achieve net zero in itself is an essential step to delivering on the Paris Agreement, the decision on the date by which net zero must be reached is just as important. In the end, both the substantive target destination and the gradient of the trajectory to reach it are what determine the outcome for the climate, with interim targets crucial for setting that trajectory.

Although many now agree on the need for net zero targets, fewer agree on the date for when specific actors should achieve it. While the UK government set a 2050 date based on advice from the Committee on Climate Change, the 2019 advocates of a UK Green New Deal suggested a target date of 2030, and the activist group Extinction Rebellion has demanded 2025.

Deciding on the date for net zero involves a series of trade-offs with respect to where benefits and costs will fall for different parts of society. If the chosen target year is too early, it may be disruptive to people’s lives and livelihoods and make a ‘just transition’, in which workers from polluting industries are supported and reskilled, more difficult10.

If the date is set for too far into the future, however, it could fail to give a sufficiently strong stimulus to mitigation in the present, and as such increase the risks of damaging climate impacts. These harmful impacts are not only likely to be felt unequally, but a far off date may also pose problems in terms of high-income countries bearing their fair share of emissions reductions in accordance with the principle of “common but differentiated responsibilities and respective capabilities” set out in the Paris Agreement.

When countries set their target dates for will depend on their specific context. On the basis of the Paris Agreement principles that developed nations should lead the effort on climate change, there is a strong equity-based case for industrialised nations to set net zero greenhouse gas emissions targets by an early date, such as the UK has done with its target for net zero greenhouse gas emissions by 2050, and preferably achieve net zero carbon dioxide emissions earlier than that. Such concerted early action by these nations would provide the space for aligning industrial development and emissions reduction in the rest of the world.

In the end, setting a target date for reaching net zero is likely to involve a range of considerations, the importance of which will vary by country. They include a desire to take international leadership; costs of delivering a rapid net zero target versus the benefits and co-benefits of doing so (e.g. job creation in the green economy, achieving ‘first mover’ status in new industries, reducing existing, often dangerously high, levels of urban air pollution) public attitudes towards climate change; the balance between state intervention in the economy and market forces; state capacity; and technological feasibility. The UNFCCC’s first Global Stocktake, scheduled for 2023, will be a critical opportunity to assess the ambition, completeness and consistency of national targets.

Tackling the right emissionsNet zero targets should include all relevant greenhouse gases. As mentioned, carbon dioxide (CO2) needs to fall to net zero in order to stop warming, which makes it a crucial component of any net zero target. Its long-term, cumulative effect on the climate means that how soon it reaches net zero, and the pathway for doing so, is also crucial.

However, a target focussed solely on CO2 risks distorting mitigation actions and costs, and potentially failing to comply with the Paris Agreement. Specifically, targets should include all seven greenhouse gase groups reported under national inventories (i.e. CO2, CH4, N2O, HFCs, PFCs, SF6 and NF3), commonly reported in terms of carbon dioxide equivalent (CO2e)7. For HFCs and PFCs, disaggregated data by chemical should be provided11. Progress towards net zero is therefore represented by the balance of emissions and removals of all these gases aggregated in CO2e terms.

As well as covering all greenhouse gases, national net zero targets must also encompass all economic sectors. Without such economy-wide coverage, there is again a risk of severe distortion of mitigation actions, costs and overall efficacy.

4Destination net zero: setting and delivering ambitious, credible targets

In practice, the rules on carbon accounting for governments are set at an international level, under the umbrella of the UNFCCC15. Most remaining areas of controversy relate to out-of-country emissions including international aviation and shipping; the potential for domestic emissions to be

offset by international credits; and emissions from the manufacturing of goods offshore, which are nevertheless consumed in-country.

Current national reporting of greenhouse gas emissions (via the UNFCCC) is on a ‘production’ basis i.e. those emissions that occur within a defined territory. As such, progress on emissions reductions in the UK, for example, and the net zero target itself, are based on these production-based emissions.

In reality, the UK is responsible for greenhouse gas emissions beyond its borders through the goods and services the country imports. For example, around half of the food consumed in the UK is produced overseas16. When setting a net zero target, governments should provide clarity on their approach to what emissions will – and will not – be covered within the target.

Box 2: Defining net zero greenhouse gas emissions Emissions of other greenhouse gases relate to global temperature differently than CO2 does, largely due to their differing lifetimes in the air. When including other greenhouse gases beyond CO2 (such as methane) into targets, reaching net zero becomes a matter not of ‘carbon neutrality’, but rather of ‘climate neutrality’. Here, the climate outcome from ‘net zero emissions’ depends on the metric used to aggregate emissions into a single total.

The approach adopted by the UNFCCC – and hence many others – is to report all emissions in terms of CO2-equivalent using the GWP100 metric. GWP100 (despite its name) indicates the relative impact of emissions of different greenhouse gases on global temperatures in 20-40 years’ time. On timescales longer than 40 years, GWP100 overstates the temperature impact of methane and other short-lived greenhouse gases, while understating their impact on shorter timescales12.

As such, the climate outcome from maintaining net zero emissions based on GWP100 depends on the greenhouse gas mix: residual shorter-lived emissions balanced by CO2 removal eventually leads to cooling; on the other hand, net positive CO2 emissions balanced by net negative emissions of shorter-lived gases (which is possible in accounting terms if offsets based on reduction of methane emissions are used, for instance) causes further warming.

Other metrics have been proposed, some of which more accurately reflect the temperature outcomes of different greenhouse gas emissions13,14. However, any “net zero” state that involves significant offsetting between emissions and removals of gases with different lifetimes is inherently unsustainable.

Net zero strategies should be aware of these differences in climate outcome from different greenhouse gas emissions. In order to ensure temperature is stabilised, net zero targets which cover all greenhouse gases should ensure that the component of CO2 emissions specifically falls to zero or below.

Box 3: Sub-national targets: considerations for cities, organisations and companiesAt sub-national scales, such as cities, local councils and companies, a key issue in setting a net zero target relates to what is known as the ‘scope’ of counted emissions. For businesses, for instance, most targets will include Scope 1 emissions, arising on companies’ own premises, as well as Scope 2 emissions, which are those from off-site power needed to run their operations.

More challenging are Scope 3 emissions, which are those produced across the wider supply chain, and by clients who use a company’s product or service. In practice, for many cities, councils and industries, these Scope 3 emissions will be the ones making a real difference to global warming, and as such it is imperative that they are considered as part of net zero planning17.

As with the net zero commitments of national governments, subnational targets should encompass all greenhouse gases and all relevant sectors. However, at these sub-national scales especially, there are major limitations in terms of data availability, inconsistent use of scopes and metrics, and capacity to plan, implement and report on net zero targets.

To deliver on the UK-wide net zero target there is now an urgent need to ensure emerging plans at these sub-national scales are robust, consistent and achievable. This must include strong cooperative action by the devolved administrations that reflects differing contexts and capacities but that in aggregate still delivers a rapid, resilient and sustainable transition to net zero for the UK as a whole18.

5Destination net zero: setting and delivering ambitious, credible targets

Beyond the target: planning for delivery For any business, city, country, or other organisation setting a net zero target, it is imperative to accompany it with senior-level backing and a clear plan of how it will be achieved. Plans must then move swiftly to set in motion the appropriate policies and actions and to establish regular checks along the way to monitor and report progress against it. The UNFCCC’s Race To Zero campaign has summarised the following four Ps, in partnership with experts and practitioners19:

Pledge: Make a high-level and ambitious commitment to reach (net-)zero in line with global efforts to limit warming to 1.5°C. For example, the UK government has enshrined its target in legislation. For companies and other non-state actors, the pledge should be made at head-of-organisation level.

Plan: Set out what activities will be undertaken to achieve net zero, especially in the short-to medium-term. Set interim targets to meet in the next decade, which reflects a fair share of the required 50% global reduction in CO2 by 2030, identified in the 2018 IPCC Special Report as necessary to keep warming to 1.5°C.

Proceed: Act immediately toward delivering on the net zero plan across all sectors, consistent with reaching any interim targets which have been set out.

Publish: Commit to report progress at least annually. All national governments report to the UNFCCC, and all other actors should consider including reporting via platforms that feed into the UNFCCC Global Climate Action Portal, if possible.

Companies and individual citizens are likely to benefit from the certainty and transparency this provides, enabling them to plan effectively. Reporting on progress also means that governments can more effectively be held to account, both via parliamentary process and the courts, for any failure to meet the interim and final targets.

Grasping the opportunity at COP26An encouraging number of net zero targets have already been set, and the recent announcements of commitments by China, Japan and South Korea shows the continued momentum behind such targets and the clarity of purpose they provide20.

There is much more to be done, however, to ensure that the act of setting net zero targets helps the world reach net zero emissions at the necessary pace. While net zero targets provide a clear and attractive framing of ambition – whether at government, sub-national or organisational level – their delivery requires sustained action across decades, starting with immediate action now.

COP26 will be a moment for bringing forward more commitments and putting all countries and organisations on track to reach net zero emissions and achieve the Paris Agreement. It will also be a moment to ensure that all targets are transparent and evidence-based and have a clear and coherent plan for how they will be delivered.

1. Rogelj, J., Schaeffer, M., Meinshausen, M., Knutti, R., Alcamo, J., Riahi, K., Hare, W., 2015. Zero emission targets as long-term global goals for climate protection. Environmental Research Letters 10, 105007. https://doi.org/10.1088/1748-9326/10/10/105007

2. ECIU (2020). Net zero: the scorecard Available at: https://eciu.net/analysis/briefings/net-zero/net-zero-the-scorecard

3. Allan, J. et al. (2020). A net-zero emissions economic recovery from COVID-19. COP26 Universities Network. Available at: www.imperial.ac.uk/grantham/publications/a-net-zero-emissions-economic-recovery-from-covid-19.php

4. IPCC. (2018): Summary for Policymakers. In: Global warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty [Masson-Delmotte, V. et al (eds)]. World Meteorological Organization, Geneva, Switzerland, 32 pp.

5. Fuglestvedt, J. et al. (2018). Implications of possible interpretations of ‘greenhouse gas balance’ in the Paris Agreement Phil. Trans. R. Soc. A.376 : 20160445.

6. IPCC, 2019: Summary for Policymakers. In: Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems [P.R. Shukla et al. (eds.)]. In press.

7. IPCC. (2018): Global warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty [Masson-Delmotte, V. et al (eds)]. World Meteorological Organization, Geneva, Switzerland, 32 pp.

References

6Destination net zero: setting and delivering ambitious, credible targets

how to cite this paperPetersen, K., Allen, M., Hilson, C., Jones, C., Reay, D. and Smith, S. M. (2021). Destination net zero: setting and delivering ambitious, credible targets. COP26 Universities Network Briefing.

8. de Coninck, H. et al. (2018). Strengthening and Implementing the Global Response, in: Abdulla, A., Boer, R., Howden, M., Ürge-Vorsatz, D. (Eds.), Global Warming of 1.5 °C: An IPCC Special Report on the Impacts of Global Warming of 1.5 °C above Pre-Industrial Levels and Related Global Greenhouse Gas Emission Pathways, in the Context of Strengthening the Global Response to the Threat of Climate Change, Sustainable Development, and Efforts to Eradicate Poverty. World Meteorological Organisation, Geneva, Switzerland.

9. The Royal Society and Royal Academy of Engineering (2018). Greenhouse gas removal. Available at: https://royalsociety.org/-/media/policy/projects/greenhouse-gas-removal/royal-society-greenhouse-gas-removal-report-2018.pdf

10. Abram, S., et al. (2020). Just Transition: Pathways to Socially Inclusive Decarbonisation. COP26 Universities Network Briefing. Available at: www.gla.ac.uk/media/Media_758106_smxx.pdf

11. UNFCCC. (2018). Report of the Conference of the Parties serving as the meeting of the Parties to the Paris Agreement on the third part of its first session, held in Katowice from 2 to 15 December 2018. Available at: Report of the Conference of the Parties serving as the meeting of the Parties to the Paris Agreement on the third part of its first session, held in Katowice from 3 to 14 December 2018. Addendum 2 (unfccc.int)

12. Allen, M., Fuglestvedt, J., Shine, K. et al. (2016). New use of global warming potentials to compare cumulative and short-lived climate pollutants. Nature Clim Change 6, 773–776. https://doi.org/10.1038/nclimate2998

13. Myhre, et al. (2013). Anthropogenic and Natural Radiative Forcing. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F. et al (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

14. Lynch et al (2020). Demonstrating GWP*: a means of reporting warming-equivalent emissions that captures the contrasting impacts of short- and long-lived climate pollutants. Environmental Research Letters. 15 044023.

15. IPCC. (2019). 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories. Calvo Buendia, E. et al. (eds). Published: IPCC, Switzerland.

16. Department for Environment Food & Rural Affairs. (2018). Food Statistics in your pocket 2017 – Global and UK supply. Available at: www.gov.uk/government/publications/food-statistics-pocketbook-2017/food-statistics-in-your-pocket-2017-global-and-uk-supply

17. Hertwich, E. G. and Wood, R. (2018). The growing importance of scope 3 greenhouse gas emissions from industry. Environmental Research Letters 13 104013.

18. Kuriakose, J. et al. (2018). Quantifying the implications of the Paris Agreement for Greater Manchester. University of Manchester.

19. UNFCCC (2020). Defining the “Starting Line”: Minimum criteria required for participation in the Race to Zero campaign. Available at: https://unfccc.int/sites/default/files/resource/Minimum-criteria-for-participation-in-RTZ.pdf

20. Carbon Brief, 2020. South Korea follows Japan and China in carbon neutral pledge. Available at: www.carbonbrief.org/daily-brief/south-korea-follows-japan-and-china-in-carbon-neutral-pledge

7Destination net zero: setting and delivering ambitious, credible targets

The COP26 Universities NetworkThis briefing is produced in association with the COP26 Universities Network, a growing group of more than 50 UK-based universities working together to help deliver an ambitious outcome at the UN Climate Summit in Glasgow and beyond.

The briefing represents the views of its authors (listed on page one) and not necessarily that of every University or institution participating in the network. For more information about the COP26 Universities Network, please contact r.samra@imperial.ac.uk

Priestley InternationalCentre for Climate