Learning more about net-zero carbon emissions

To keep global warming below 1.5°C, nations must reach net-zero carbon emissions by 2050. However, current national plans fall short of the necessary ambition.

Decarbonization has risen to the top of the business agenda, with 3,000 companies now committed to Science Based Targets (SBTi). Achieving net zero requires urgency and comprehensive emissions reductions, including currently difficult sources. It also calls for social and environmental integrity, including a fair net-zero transition.

What is net zero?

Net-zero carbon emissions mean that the total anthropogenic greenhouse gas (GHG) emissions released to the atmosphere are counterbalanced by an equivalent amount of GHGs removed. To achieve carbon emissions to net zero, all countries must set targets aligned with science and the Paris Agreement goal to limit warming to 1.5°C. This means setting comprehensive targets for emissions reductions across the economy and investing in carbon removal technologies if necessary.

Achieving net zero also requires long-term carbon storage, with a timescale of at least decades for geological carbon sequestration and up to a century or more for biological storage via afforestation. This substantially constrains carbon offsets’ scope, scale, and timing. Getting these right is, therefore, vital for turning net zero into a successful framework for climate action.

In addition to setting targets that align with 1.5°C science, all countries should communicate long-term low GHG emissions development strategies to show how they will get to net zero by around mid-century. This will enable all nations to align their near-term emissions reduction goals with the ambition of a net-zero world, considering national circumstances and economic development.

It is essential to ensure that all efforts to reach net zero are conducted fairly and equitably, especially for workers in high-carbon industries. This includes ensuring that the transition’s costs and benefits are distributed justly and supporting communities to build resilience through local actions.

What is the definition of net-zero carbon emissions?

As a scientific concept, net zero is the balance between sources and sinks of greenhouse gases on a sustained basis over matching time scales. The Paris Agreement requires that we reach net-zero emissions if we are to keep global temperature rises below 1.5°C. This will require deep and widespread cuts in emissions and scaling up removals to offset remaining anthropogenic carbon dioxide (CO2) and other greenhouse gas emissions. To be truly effective, removals must also be permanent. Otherwise, removed carbon may return to the atmosphere through unsustainable forest destruction or poor carbon storage.

The challenge for policymakers is translating the globally defined constraint of net zero into specific decarbonization pathways for nation-states, sub-national entities, cities, and companies. These individual targets must reflect the urgency of climate change and social and environmental priorities, including preserving biodiversity, supporting local economies and livelihoods, and ensuring equitable access to low-carbon technologies and services.

The most comprehensive approach to net-zero will require the full range of available climate action: reducing energy use and switching to clean electricity; generating renewables, such as wind and solar power; afforestation and other land-use changes that increase CO2 sequestration; and permanent carbon capture and storage. While many countries are already pursuing these measures, it is still essential to focus on further deep cuts in hard-to-eliminate emissions and strengthen and broaden the scope of mitigation options.

What are the benefits of net-zero carbon emissions?

Achieving net zero will have significant costs, but the benefits of limiting climate damage and industrial innovations outweigh these upfront costs. The transition would also create new business opportunities.

However, the structural and economic transformation required to reach net zero emissions must be approached socially justly.

In addition, achieving net zero will require moving beyond carbon neutrality to the more rigorous goal of ‘net zero’ – which requires that companies reduce their emissions as much as possible before offsetting any remaining unavoidable emissions. This approach has been defined by organizations such as the Science-based Target Initiative (SBTi) and is used by companies to offset their global touring emissions.

Achieving net zero will also need to be permanent – that is, carbon that has been removed cannot return to the atmosphere through, for example, deforestation or improper storage.

What is the goal of net zero?

The international scientific consensus is that to avoid the worst climate damage, global net human-caused emissions must fall to zero and be counterbalanced by carbon removal. This is a global objective, but actions will be driven by national governments, cities, and companies making their plans.

Achieving net zero requires deep and broad cuts in greenhouse gas emissions and scaling up carbon removal. It also calls for ensuring that any removed greenhouse gases do not return to the atmosphere through, for example, deforestation or improper carbon storage. Therefore, the goal of net zero demands firm constraints on the scope, timing, and governance of both carbon removal and offsets.

The path toward net zero must be approached fairly and equitably. The transition will require that workers tied to high-carbon activities be reskilled and redeployed and that long-term investment decisions are made with net zero in mind. It will also require the burden of achieving the global target to be shared relatively between countries and across regions, industries, and population groups.

Looking ahead

Achieving a global energy sector on the path to net zero by 2050 will require unprecedented transformations in how energy is produced, transported, and used worldwide. These changes are needed to create a sustainable and equitable energy system and to limit warming to 1.5°C or below.