The sixth evaluation report of the Intergovernmental Panel on Climate Change (IPCC), called AR6, is an important milestone in the scientific understanding of climate change and its impacts. The purpose of the report is to provide up-to-date and reliable information on understanding climate processes to support policy decisions and mitigation and adaptation actions.
During the period 2011 to 2020, the average global surface temperature increased by about 1.1°C over the reference period from 1850 to 1900. This increase was greater over land areas, reaching about 1.59°C , compared to the oceans, of approximately 0.88°C.
It is undeniable that human influence has caused the atmosphere, oceans and land surface to warm. Rapid and widespread changes were observed in climate systems, such as the atmosphere, ocean, cryosphere (areas with ice) and biosphere (set of all living beings). The scale of these recent changes in the climate system – as a whole – and the current state of many aspects of the climate are unprecedented, spanning centuries and even thousands of years.
Scientific evidence indicates that human activities such as burning fossil fuels, deforestation and greenhouse gas emissions contribute significantly to the observed warming. These activities have increased atmospheric concentrations of gases such as carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O).
Global greenhouse gas (GHG) emissions implicit in Nationally Determined Contributions (NDCs) indicate that, by 2030, global warming is likely to exceed 1.5°C over the 21st century, making it more challenging to limit warming below of 2°C.
However, mitigation policies have contributed to the reduction of global energy and carbon intensity – in greenhouse gas (GHG) emissions, for more than a decade. Low emission technologies are more accessible, with low or no emission energy, buildings, transport and industry options available.
Behaviors, spatial, economic and social barriers are created as a result of these pathways, as well as the choices made by policy makers, citizens, the private sector and other stakeholders have a direct impact on the development of societies.
Limiting man-made global warming requires reducing anthropogenic CO2 emissions to zero. To achieve the targets set by the 1.5°C and 2°C carbon budgets, it is necessary to implement rapid, deep and, in most cases, immediate reductions in greenhouse gas (GHG) emissions across all sectors.
Exceeding a certain level of warming and then returning (ie exceeding the threshold and then reducing emissions) entails additional risks and can lead to potentially irreversible impacts. To achieve and maintain net negative CO2 emissions on a global scale, it is necessary to implement strategies to remove CO2 from the atmosphere.
These actions are key to reducing global warming and avoiding the adverse impacts of climate change. Efforts must be made across all sectors, including energy, transport, industry, agriculture and land use. This will require adopting low-carbon technologies, increasing energy efficiency, investing in renewable energy, transitioning to sustainable agricultural systems, and protecting and restoring ecosystems.
