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. This is the state of net-zero carbon dioxide emissions (carbon neutrality) at which global warming stops.

Net zero is the internationally agreed upon goal in a Paris Agreement in 2015, and the IPCC concluded the need for net zero CO2 by 2050. In December 2020, five years after the Paris Agreement, the Secretary-General of the United Nations António Guterres warned that the commitments made by countries in Paris were not sufficient and were not respected. He has urged all other countries to declare climate emergencies until carbon neutrality is reached.

To achieve absolute zero or zero emissions in the process, a Race to Zero campaign was launched to raise ambition.

The campaign has these aims:


 * recognize the global climate emergency
 * keeping global heating below the 1.5°Celsius goal of the Paris Agreement
 * put inclusive climate action at the center of all urban decision-making
 * pledge to reach net-zero in the 2040s or sooner, or by 2050 at the latest, in line with global efforts to limit warming to 1.5°Celsius

Other possible actions to reduce greenhouse gas emissions are:


 * Limiting energy usage and emissions from transportation (walking, using bicycles or public transport, avoiding flying, using low-energy vehicles, carpooling), as well as from green buildings, equipment, animals and processes.
 * Obtaining electricity and other forms of energy from zero or low carbon energy sources.
 * Electrification: using electrical energy, ideally from non-emitting sources, rather than combustion. For example, in transportation (e.g., electric vehicles and electric trains) and heating (e.g. heat pumps and electric heating).
 * Using green hydrogen, produced by splitting water into hydrogen and oxygen using renewable electricity.
 * Zero carbon natural gas, where power plants efficiently and cheaply capture carbon released by burning natural gas, avoiding greenhouse-gas emissions.
 * Fuel cells (FCs) were invented in 1839 by using a reverse process to produce electricity from hydrogen and oxygen in a fuel tank. A hydrogen FC resembles a battery, but unlike a battery, it can work indefinitely, as long as it has a supply of fuel in the form of oxygen from the air and hydrogen. There is hope that FCs may one day be used more frequently in vehicles to replace the traditional combustion engine. Benefits of FCs include zero carbon emissions and reduced dependence on oil, and breaking down hydrocarbon-based fuels which reduces greenhouse gases.