KEY MESSAGES "1.5 ° C global warming, IPCC special report on the consequences of 1.5 ° C global warming compared to pre-industrial levels and related profiles in global greenhouse gas emissions in the context of strengthening the global climate change response, sustainable development and the fight against poverty "
The four main messages of the report
Climate change is already affecting people, ecosystems and livelihoods.
There are undeniable advantages in limiting heating to 1.5 ° C compared to 2 ° C or more. Every half degree counts.
Limiting global warming to 1.5 ° C is not impossible but would require unprecedented transitions in all aspects of society.
Limiting global warming to 1.5 ° C can go hand in hand with the achievement of other global sustainable development goals for improving the quality of life for all.
This report is the result of the work of 91 authors from 40 countries, and the inputs of 133 contributors. It reviewed 6000 scientific publications. Successive versions of the report have received 42,000 comments from more than 1,000 reviewers from the scientific community and governments.
Synthesis of the key points of the summary for decision makers.
The first section is about understanding 1.5 ° C of global warming.
Since the pre-industrial period, human activities have caused global warming is approximately 1 ° C (between 0.8 and 1.2 ° C).
We are already living with the consequences of this degree of warming, with the intensification of extreme events, rising sea levels, and the retreat of the Arctic sea ice, among other changes.
If the world continued to warm at the same rate, global warming would reach 1.5 ° C between 2030 and 2052.
While past emissions from the pre-industrial period until today will continue to cause changes in the climate system, these past emissions will not cause global warming to reach 1.5 ° C.
The second part of the summary for decision-makers focuses on climate change projections, potential impacts, and associated risks.
Climate models project different robustnesses between today and global warming of 1.5 ° C, and between 1.5 and 2 ° C. Every half degree of warming counts.
These differences relate to the increase in the average temperature in the oceans and over the continents, the intensification of temperature extremes in inhabited regions, the events of torrential rains in many regions, and droughts in certain regions, like the Mediterranean area.
By 2100, sea level rise would be 10 cm less if warming is stabilized at 1.5 ° C rather than 2 ° C. This would translate into 10 million fewer people exposed to the consequences of rising sea levels.
The loss of biodiversity and the risk of species extinction would be half as low at 1.5 ° C as 2 ° C on continents.
It would also lead to more limited losses in yields for cereals such as wheat, corn or rice, and other cereals, especially in sub-Saharan Africa, Southeast Asia, Central America and South America.
The world’s population exposed to water shortages would be half as low at 1.5 ° C as 2 ° C.
In the oceans, a 1.5 ° C warming will cause 70 to 90% degradation of tropical coral reefs, against more than 99% at 2 ° C. The consequences of warming in the oceans would be much higher at 2 ° C than at 1.5 ° C, with for example a greater fall in the tonnage of fisheries.
Limiting global warming to 1.5 ° C compared to 2 ° C could reduce hundreds of millions of people exposed to climate risks and likely to fall into poverty.
The third part of this summary for decision-makers concerns the emissions and transitions of systems compatible with the limitation of global warming to 1.5 ° C.
This would mean cutting global carbon dioxide emissions by 45% in 2030 compared to the level of 2010.
For comparison, limiting global warming to 2 ° C implies a reduction of these emissions by 20% by 2030.
Global carbon dioxide emissions are expected to reach "net zero" around 2050. This implies that any residual emissions should be offset by actions to extract CO2 from the air and store it in a sustainable manner.
By comparison, this carbon neutrality must be achieved in 2075 to limit warming to 2 ° C.
To limit warming to 1.5 ° C, reducing releases of climate-damaging substances other than carbon dioxide would have immediate effects on air quality and improving public health.
Limit warming to 1.5 ° C implies changes on an unprecedented scale, i.e. emission reductions in all sectors, the use of a wide range of technologies, changes in behavior, and a significant increase in investments towards low carbon options.
Rapid progress has been made in some sectors, including renewables. Such rapid progress is needed in other sectors, in particular transport and territory planning.
To limit warming to 1.5 ° C, carbon dioxide should be removed from the atmosphere throughout the 21st century.
Methods for doing this include planting trees, restoring ecosystems, using bioenergy with capture and storage, changes in land management, and other approaches that are in the early development stages today.
Large-scale extraction of carbon dioxide would have implications for food security, preservation of ecosystems and biodiversity.
The national contributions of governments made under the Paris Agreement for 3 years are not enough to contain global warming below 1.5 ° C, even with extremely ambitious and difficult actions after 2030.
To avoid exceeding 1.5 ° C of global warming in a few decades, CO2 emissions must decrease substantially before 2030, then the deployment of methods to extract CO2 from the atmosphere.
The last part of the summary for decision makers focuses on strengthening the global response to climate change, in the context of sustainable development and efforts to eradicate poverty.
The impacts of climate change and how we respond to it are closely linked to sustainable development and the United Nations Sustainable Development Goals (SDGs), which seek to balance well-being for all, economic prosperity, and the protection of the environment.
To limit warming to 1.5 ° C, there is a set of adaptation measures and options to reduce greenhouse gas emissions which, if well chosen, can have multiple benefits for the objectives of sustainable development. . This is the notion of ethical and fair transitions.
This is all the more effective when local authorities are supported by national public authorities.
Capacity enhancement of public authorities, local communities, civil society, the private sector, indigenous populations and local communities can bring the ambitious actions that would be necessary to limit global warming to 1.5 ° C.
International cooperation is critical for this to happen in all countries and for all, especially for developing countries and in vulnerable regions.
To conclude, every half degree of warming counts; every year counts; and every choice counts.
In the same section
Sunday, November 15th, 2015
The Applied Research on Renewable Energies Unit (URAER) of Ghardaïa organized on October 12th to 15th, 2014, the 3rd edition of the international seminar on new and renewable energies.