Bqe-recherche avancée

Fr. Evolution du climat, changement climatique, GIEC (Groupe d'experts intergouvernemental sur l'évolution du climat)

Esp. Cambio climático, evolución del clima

→ Anthropocene, common goods, IPCC, IPBES

This term only gives a partial account of wider and multiple developments that have serious consequences for the future of mankind. Climate science is a central piece of a complex set of disciplines that cover so many phenomena that they require an interdisciplinary approach (Abraham 2014). Scientific research has demonstrated that global warming is caused by increased concentrations of greenhouse gases, which have now reached more than 400 parts per million in the air—higher than that breathed by homo sapiens in the last 200,000 years. Global warming is intimately connected to feeding more than seven billion people, providing drinkable water as supplies dwindle and supplying electricity to billions of people who still do not have it. Global warming is a fact that has been well established since the 1800s, and has reached near unanimous consensus among the world’s climate scientists about its anthropogenic nature (Weiler and Demuynck 2017). The concept has come recently to the fore because it expresses its content in an immediate, tangible way, but it is also linked to closely related realities, studied by other sciences:

- Biodiversity (biological diversity) loss is rapid and ongoing (UNEP 2015). Over the last 50 years, humans have changed ecosystems faster and more extensively than in any comparable period of time in human history. Tropical forests, many wetlands and other natural habitats are shrinking in size. Species are going extinct at rates 1,000 times the background rates typical of Earth’s past. Trends of some 3,000 wild populations of species show a consistent decline in average species abundance of about 40% between 1970 and 2000; inland water species declined by 50%, while marine and terrestrial species both declined by around 30%. Studies of amphibians globally, African mammals, birds in agricultural lands, British butterflies, Caribbean and Indo-Pacific corals, and commonly harvested fish species show declines in the majority of species assessed. The direct causes of biodiversity loss – habitat change, overexploitation, the introduction of invasive alien species, nutrient loading and climate change – show no sign of abating.

- Humankind has to face a systematic shortage of food on a planetary scale as soon as 2050, which will lead to social unrest and consequently to political instability, in several parts of the planet and over longer periods. Overall, unsustainable consumption continues, as indicated by our growing global ecological footprint. The global demand for resources now exceeds the biological capacity of the Earth to renew these resources by some 20% (Global Biodiversity Outlook 4, 2015).

- In the field of ecological economics, researchers have indicated that either one of the two features apparent in historical societal collapses – over-exploitation of natural resources and strong economic stratification – can independently result in a complete collapse. Given economic stratification, collapse is very difficult to avoid and requires major policy changes, including major reductions in inequality and population growth rates. Even in the absence of economic stratification, collapse can still occur if depletion per capita is too high. However, collapse can be avoided and population can reach equilibrium if the per capita rate of depletion of nature is reduced to a sustainable level, and if resources are distributed in a reasonably equitable fashion.

- In geology, scientists suggested that the Holocene should be followed by the Anthropocene. Already in the mid-nineteenth century, several geologists sought to recognize the growing power of humankind by referring to the present as the ‘anthropozoic era’ and other similar names. Human impacts on the environment surged in that period, which has been called “the Great Acceleration”. The idea has gained traction only in the past few years, however, in part because of rapid changes in the environment, as well as the influence of Paul Crutzen, an atmospheric chemist at the Max Plank Institute for Chemistry in Mainz, Germany. In the 1970s and 1980s, he made major discoveries about the ozone layer and how pollution from humans could damage it. In 2000, he and Eugene Stoermer of the University of Michigan in Ann Arbor argued that the global population has gained so much influence over planetary processes that the current geological epoch should be called the Anthropocene. In the opinion of many geoscientists, the magnitude of changes justifies a new division of geological time: through mining activities alone, humans move more sediment than all the world’s rivers combined. Homo sapiens has also warmed the planet, raised sea levels, eroded the ozone layer and acidified the oceans (Abraham 2014).

Despite these sound scientific data, there remain a few high-profile scientists who have continued to put forth alternative explanations for observed climatic changes across the globe, which has caused part of public opinion to reject the anthropogenic theory. However, contrarian arguments against mainstream thinking have been strongly criticized in the scientific literature, and have not befallen the prominent consensus studies (Abraham 2016). Equally worrying is the fact that those “global warming skeptics” have sometimes politicized these pseudo-arguments, to such a point that the American Environmental Protection Agency, for example, now officially doubts the science connecting carbon emissions and climate change (Union of Concerned Scientists 2017). EPA’s Office of Science and Technology Policy deleted the word "science" from the description of its mission and the Administration cut program funds that protect the environment and our health—especially those focused on climate and earth science.


International conventions

In December 2014, one accomplishment of the Lima agreement was to end the longstanding division of the world into only two kinds of countries, developed and developing, whose obligations had been defined according to their level of development by the UN Framework Convention on Climate Change signed in 1992: the rich countries had compulsory obligations, while poorer countries merely had been required to make voluntary efforts. That binary distinction looked increasingly obsolete, as the larger developing countries, such as China and Brazil, emerged as economic superpowers and major greenhouse-gas emitters (Jacobs 2014).

The UN Framework Convention on Climate Change (UNFCCC, 1992) and the Kyoto Protocol (1997, into force 2005) provide a basis for international co-operation, along with a range of partnerships and other approaches.The latter’s emphasis was on legally binding commitments, with targets and timetables set in advance of state action, was a demanding approach, required greater than available political commitment to succeed and was actually not very efficient.

The 2015 United Nations Climate Change Conference in Paris was the 21st yearly session of the Conference of the Parties (COP21) of the UNFCCC and the 11th session of the Conference of the Parties (CMP11) of the Kyoto Protocol. COP21 (the Paris Agreement) reached a global agreement on the reduction of climate change, the text of which represented a consensus of the 196 Parties attending it, and was signed by 174 countries in New York on 22 April 2016. It entered into force on 4 November 2016. 148 of 197 Parties to the Convention have ratified it (June 2017). The first session serving as the Meeting of the Parties to the Paris Agreement (CMA 1) took place in Marrakech, from 15-18 November 2016. COP21 negotiations took a different approach from previous agreements, beginning with national pledges for voluntary action and general arrangements for periodic review and transparency. Its effectiveness will depend in considerable measure on the review process, to assess the fulfillment of national commitments over the next few years.

One improvement at that time was that the Working Group on Climate Change took a longer-term perspective, aiming to catalyze new understandings of the politics, sociology, and political theory of climate change policy in a historical and comparative perspective. However, what is increasingly described as a turn-point in the history of humankind has not prevented the US from deciding in June 2017 to withdraw from the Paris agreement, which could cause to release 0.4 gigatonne more carbon dioxide in annual emissions in the year 2030, plus another 1.8 gigatonnes CO2 in 2030, about 31 percent of 2005 U.S. emissions, if the climate plan created by the Obama administration has not yet been fully implemented (Höhne et al. 2017, Scientific American, May 31, 2017). As the COP 24 approaches in Poland, the states that signed the Paris Agreement are not necessarily in a better position, since only 16 of the 197 signatories (Algeria, Canada, Costa Rica, Ethiopia, Guatemala, Indonesia, Japan, Macedonia, Malaysia, Montenegro, Norway, Papua New Guinea, Peru, Samoa, Singapore and Tonga) comply with their commitment. This means that, as things stand, the signatories to the Paris Agreement are preparing for a global warming of 2.7° to +3.2° from 2030, instead of limiting the increase to 1.5° to 2° in 2050.