
More and more nations, cities, businesses and financial institutions are making commitments towards net zero emissions as part of an effort to contain global temperature rise. This commitment is crucial if we hope to limit its further acceleration.
Emissions reductions must be prioritized early and include all sources of greenhouse gases including carbon dioxide (CO2), methane and nitrous oxide. Furthermore, equity considerations must be integrated into net zero ambition.
The concept
Net zero emissions is not only a technical concept or climate change target; it has become an increasingly significant guiding principle in global efforts against climate change. It sets an appropriate timetable for carbon pollution to decline and to reach sustainable greenhouse gas levels in our atmosphere.
Reaching net zero emissions is no simple task. To reach it requires balancing out the carbon that is produced against what can be removed from the air so as to achieve no net increase (see Fig 1). This includes not only reducing production of CO2, but also cutting emissions of other potent greenhouse gases like methane, nitrous oxide and fluorinated gases such as methane.
Science offers no room for complacency: scientists estimate that in order to stay below 2 degrees Celsius, net emissions must reach zero by around 2050 at the latest. While this goal may seem impossible, it is entirely achievable as long as we frontload emission reductions in order to speed their pace of decline and cover all sources (including difficult ones like hydrocarbon emissions) with reduction efforts (see Fig. 2).
Organizations will need to assess their own emissions, identify ways of reducing them internally or buying carbon offsets from projects elsewhere, as well as being vigilant to any unintended side-effects such as non-additionality or the use of carbon removals that exacerbate ecological damage and accelerate climate change.
What is net zero?
Reaching net zero emissions requires not only cutting greenhouse gas emissions to zero, but also extracting an equivalent amount of carbon from the atmosphere (known as negative carbon dioxide). Achieving net zero is one of humanity’s greatest challenges – one which requires radical transformations of production, consumption and travel patterns: switching from fossil fuels to renewable energy; modernizing buildings and factories with efficiency upgrades; and shifting away from meat-rich diets.
Nearly every country on the globe signed the Paris Agreement in 2015, pledged to limit global warming to no more than 2 degrees Celsius while striving for 1.5 degrees. According to the Intergovernmental Panel on Climate Change (IPCC), meeting this global temperature goal requires reaching net zero carbon and other greenhouse gas emissions such as methane, nitrous oxide and fluorinated gases by about 2050.
Reaching net zero requires individual organizations to determine how much greenhouse gases they emit and then lowering those emissions to zero, typically by undertaking projects that remove greenhouse gases from the air, such as installing heat pumps in office buildings or planting trees. Some businesses can even purchase carbon offsets to lower total emissions if local efforts do not suffice in meeting national targets.
The science
Net zero climate policy rests on the principle that, to limit global temperatures to 1.5 degrees Celsius or below, carbon emissions have an annual budget. If total releases go over this limit, additional measures such as reduced emissions from other sources or removal into sinks must be implemented in order to keep climate change at bay.
Current technology exists to drastically reduce carbon dioxide and greenhouse gas emissions in sectors like energy, transport and agriculture; however, to achieve net zero will require significant investment and innovation to bring these technologies to market at scale. This requires creating affordable and sustainable alternatives to fossil fuels in areas like heating, cooling and mobility, while also targeting hard-to-abate sources of emissions like methane from agricultural processes and nitrous oxide from fertilizers.
Governments are setting net zero targets and many have included them into national climate laws. Businesses and financial institutions are also making net zero pledges; ECIU and Oxford University’s Net Zero Tracker shows this development with its list of countries, companies and investors making commitments towards reaching this goal.
Net zero success hinges on environmental integrity: selecting projects and policies which can be verified, accurately accounted for and have minimal risk of non-additionality or unwanted side-effects. Achieveing net zero requires allocating its burden between richer nations with higher emissions per capita who require greater action to reach this goal than poorer ones do.
Getting there
Achieve net zero requires taking an extensive approach to climate action. This should include community groups, city administrations and regulatory bodies, central banks and international financial institutions as well as courts. Furthermore, its implementation must create stronger societal support and legitimacy amongst its target publics.
Countries, particularly major emitters like China, India and the US, are becoming more committed to setting ambitious national targets or “nationally determined contributions” towards reaching net zero emissions globally. It is critical that their pledges be clear and enforceable.
Reaching emissions reductions required for keeping global temperature increases to no more than two degrees Celsius requires an immediate transition to clean energy, including renewable sources like batteries, solar PV panels and demand response technologies that rapidly scale electricity generation. Achieve net zero involves rapidly scaling up electricity generation using technology like batteries, solar PV panels and demand response and substantially reducing carbon intensity across sectors (i.e. generating each unit of energy produced using no more than the equivalent emissions from one small car’s worth of CO2). To reach this goal requires rapid action – taking immediate steps toward clean energy alternatives and carbon intensity reduction across sectors – along with massive investment in batteries solar PV panels and demand response systems – in rapid scale-up electricity generation technology such as batteries to rapidly scale up electricity production; reductions in carbon intensity across sectors means every unit must generate no more than its own emission (ie equivalent emissions like that produced when producing it).
Reducing emissions through natural means such as reforestation and technologies that remove carbon from the atmosphere such as direct air capture and storage will remain key components. Individual consumer decisions to buy electric vehicles or energy efficient appliances; take public transit instead of long-haul flights; or foregoing them altogether will also contribute significantly.