To curb global warming to 1.5°C, the world must achieve zero emissions by approximately 2050. This has led to a surge of countries and companies committing to achieving net zero. However, net zero is more than just a scientific concept or technical target. It also needs to be implemented effectively.
What is net zero?
As the name suggests, net zero is about achieving an overall balance between greenhouse gases produced and those taken out of the atmosphere. The term often refers to global carbon neutrality, although many other ways exist to describe the concept.
The term emphasizes the need to reduce all human-caused emissions and get them back into balance as soon as possible, as this is essential to preventing catastrophic climate damage. Science shows that the Earth has a finite budget of heat-trapping gases, which means that removals into sinks must offset any more carbon dioxide added to the atmosphere.
Reaching net zero requires significant reductions in all sectors of the economy, including energy, buildings, industry, and transport. It also involves transforming agriculture, forestry, and waste. The shift will require unprecedented innovation and investment, especially in new technologies to replace fossil fuels in the power sector – responsible for around three-quarters of current emissions – and the transition to renewable energy.
The scientific community agrees that we need to drastically reduce human-caused emissions to net zero as soon as possible. This will help avoid the worst climate damage and drive economic and social benefits through more sustainable growth. Over 100 regional governments, 800 cities, and 1,500 corporations have adopted the net zero goal. This is a considerable achievement, but many of these targets are voluntary and allow too much discretion in designing their net-zero pathways.
What is the goal of net zero?
Net zero is a scientific idea and a framework to organize and comprehend global efforts to combat climate change. This framework is becoming more prevalent and essential. It is a ‘decarbonization target’ which aims to balance all ongoing GHG emissions from sources with GHG removals.
As agreed in the Paris Agreement, limiting global warming to 1.5 deg C is necessary. This will require emissions to peak by 2030 and rapidly reduce to net zero by 2050.
The goal is to achieve this by switching from high carbon-emitting fossil fuels to lower-carbon options and counteracting residual emissions through active carbon capture and storage. This will require transforming the entire energy system and changing land-use systems and industry, including agriculture and forestry.
A key issue is the longevity of storage: geological storage is likely to be possible for millennia, but biological storage in, for example, afforestation projects can range from less than a decade to over a century, depending on governance and ownership, and biophysical factors.
Many individual companies, cities, states, countries, and regions have already set net-zero targets or aspirations. However, to be effective, these must address all scopes of emissions, be fully transparent and exclude carbon offsets. In addition, they must be based on a plan of immediate and urgent reductions in domestic emissions.
How can we achieve net zero?
The goal of net zero is to achieve an overall balance between greenhouse gas emissions produced and removal from the atmosphere. It’s like a set of scales tilted by producing carbon pollution.
Getting to net zero will require significant reductions in all sectors of the economy. In the energy sector, where most countries’ emissions come from, this will mean a switch to low-carbon electricity from renewable sources such as wind and solar. This will also require reducing emissions of other greenhouse gases from heating, cooling, transport systems, and agriculture.
But most importantly, achieving net zero will require a broad coalition of supportive stakeholders. This is already starting to happen as the science of climate change reaches community groups, city halls, corporate board rooms, and regulatory agencies. The key will be operationalizing the net zero concepts to increase public legitimacy.
What are the challenges?
Reaching net zero carbon emissions is one of our most significant global challenges. A significant shift is necessary in the global economy, specifically in energy, transportation, and construction. This includes switching to cleaner forms of electricity, such as renewables, and transforming how we heat our homes and move around.
The energy sector accounts for three-quarters of all greenhouse gas emissions, so reducing these is critical to averting climate change. But we also need to reduce emissions from other sectors, such as land use and agriculture, and deploy technologies that can remove greenhouse gases from the atmosphere – known as harmful emissions.
Getting to net zero will require a global effort involving all countries, businesses, and individuals. The most successful efforts will be those that build broad societal support for the challenge. This is already happening, with coalitions on net zero forming in cities, regions, and industry sectors worldwide.
Achieving net zero will also require a clear framework through which entities can set and communicate their targets, including information on the scope of these targets. Finally, it will be necessary to ensure that the science behind these targets is credible.