History and origins of the Net Zero objective
2005
In 2005, Myles Allen and Dave Frame, while preparing a presentation on the results of their climate models, they devised the concept of “Net Zero“ on a train bound for Exeter.
Until that time, the climate problem was often defined in terms of Number of greenhouse gas molecules in the atmosphere.
2008
Allen and Frame discovered something revolutionary about Global Warming, then published in the journal Nature in 2008: they discovered that the time needed for the planet to absorb greenhouse gases and that necessary for global warming, due to higher CO₂ concentrations, are similar.
In other words, if CO₂ emissions are zero, the two processes They balance Each other and the Global average temperature remains constant, without increasing or decreasing further.
This means that for every additional ton of CO₂ introduced into the atmosphere by human activity, there will be an increase in the maximum temperature attainable by the planet.
2015
After the publication of the article in Nature, the term Net Zero has entered scientific reports, such as those of the Intergovernmental Panel on Climate Change (IPCC), and in international agreements, such as the2015 Paris Agreement.
The Paris Agreement established the need to achieve this balance by the second half of the century. Since then, the concept of Net Zero it has become an organizational imperative: nations, regions, cities and companies are trying to develop solid and verifiable transition strategies.
2023
Today, 91% of global GDP is characterized by national targets of Net zeroing by governments, compared to 68% in December 2020.
Gli Objectives of Net Zero they also differ in the timing and in the way in which companies plan to achieve their goal. It is important to find universal standards to recognize the decarbonization strategies of value and propose them as best practices for a correct path of reducing and offsetting emissions.
The science behind Net Zero: the scenarios of global warming
The United Nations and the IPCC: why 1.5°C?
Before the signing of the Paris Agreement, the United Nations Convention on Climate Change (UNFCCC) worked with the intention of containing theIncrease in global temperature at less than 2°C.
The scientific research evaluated in the reports ofIPCC However, they have demonstrated that an increase in temperature to 2°C would pose dangerous risks for many regions of the world, in particular for small island states and developing countries.
To further improve scientific understanding of the impacts of 1.5°C and of the mitigation paths, the UNFCCC asked the IPCC to produce what later became the 2018 Special Report on Global Warming of 1.5°C.
The Report provided the first comprehensive assessment of mitigation paths and energy system transitions consistent with the 1.5°C warming limit set by the Paris Agreement.
Article 4.1 of the Paris Agreement states that global emissions they must receive a setback and start the descent towards zero net emissions. The zeroing of emissions must take place by 2050, in order to limit damage to the planet and allow humanity a sustainable future.
1.5°C VS. 2°C: a concrete example
To understand the difference in the climatic consequences that could occur on our planet in the two scenarios of an increase in temperature to 1.5°C and 2°C, we can give a concrete example.
If the increase in global temperature were limited to 1.5°C, 14% of the world's population would be exposed to extreme heat waves once every five years. But if the temperature were to rise by 2°C, this figure would be three times worse, affecting 37% of the population.
This means that keeping the temperature below 1.5°C would reduce the risk for 420 million people from frequent extreme heat waves and 65 million from excessive heat waves. In addition, if the global temperature rise reaches 2°C, some habitats they wouldn't survive. By limiting the temperature increase to 1.5°C, the decline of coral reefs, while still high, would be 30 times lower than an increase of 2°C.
To limit global warming to 1.5°C, profound transformations are necessary in energy, industrial, urban and territorial systems on a global scale, with the aim of achieving zero net emissions of CO₂ by 2050 and an immediate reduction in greenhouse gas emissions.
The measures necessary to achieve this objective:
- Almost complete decarbonization of the energy system and industry, with the goal of achieving a zero-emission energy supply by the middle of the century.
- Elimination of CO₂ eq emissions associated with agriculture, forestry and land use.
- Reduction of greenhouse gases in addition to CO₂ in all sectors, including Methane (CH4), Nitrogen Monoxide (N20) and Hydrofluorocarbons.
- Removing CO₂ eq from the atmosphere to neutralize residual emissions and, potentially, support net negative emissions that reduce the CO₂ accumulated in the atmosphere over time.
