what is this date?

Wednesday 1 ^er August 2018 is the "day of overtaking" ecological, according to the Global Footprint Network, an international research institute established in California. From this date, humanity consumes more natural resources and emits more greenhouse gases than Earth is able to produce or absorb during one year.

This symbolic date is accompanied by another striking figure: at this rate of consumption, it would take 1.7 planet to meet the needs of men. We have only one available for the moment

These indicators, taken up by the media and commented by environmental NGOs, who advocate for a more sustainable way of life, nevertheless raise questions. 19659006] Read the article of 2017:
        
    
          Since today, humanity lives on credit
          

How is the day of overcoming calculated?

To measure the pressure of human activity on a territory, it suffices to compare two notions:

• the ecological footprint of the population, c ' that is, the natural resources that humanity needs to feed, shelter, move and compensate for the waste it generates, including greenhouse gases. This notion is then reduced to a surface: a field to produce cereals, a pasture for livestock, a forest for wood, an ocean for fish … but also the surface needed to absorb CO ₂ produced by human activities. It depends on the number of inhabitants and their way of life

• the biocapacity or biological capacity of a territory, that is to say the area needed to produce renewable natural resources and ecological services.

The Global Footprint Network performs these calculations, measured in "global hectares", for each country, from a large number of data, such as cultivated or forest land, energy consumption, especially from UN agencies (IPCC, FAO …) which are updated annually, as specified in their methodology

Earth's biocapacity was estimated at 12.2 billion global hectares, while humans use the equivalent of 20 billion hectares a year, or 1.7 times more.

To make this figure even more accessible, NGOs have converted it into an annual "debt": humans consume the renewable resources of the Terr e in seven months, and live theoretically "on credit" the rest of the year. A calculation that recalls other symbolic dates to the questionable method: the day of tax liberation or the time when women should stop working.

Why is this figure criticized?

Getting a cipher for public opinion often requires "shortcuts". In 2010, Leo Hickman, environmental journalist, lamented in Guardian that this indicator aggregates "apples and pears" that is to say adds data of a different nature than greenhouse gas emissions, maize harvests or loss of primary forest. He also notes that the calculations are refined every year, which makes the fate change. Indeed, when we published an article on this subject in 2015, the overrun occurred on August 13th. However, the latest data published in 2018 now set the overrun at 6 August 2015, one week earlier.

The concept of "global hectares" is also problematic, since this average does not make it possible to distinguish productivity from hectares of cereals in France or the Maghreb, as explained by a specialist interviewed by Libération .

Another subtlety: some countries have a higher biocapacity than others and are therefore ecological "reservoirs" . Thus, Brazilians have the same ecological footprint as Macedonians, but their biocapacity is five times higher because of the Amazon rainforest. Each French person consumes 2.9 times what the Earth can provide to meet his needs, but only 1.8 times the capacity of the French territory (thanks to the ecological wealth of Guyana).

See also:
        
    
                What does the "day of the pbading of the Earth" mean?
    

If some indicators are real (the number of trees cut to produce wood or the production of cereals), most of the debt is carbon emissions that nature can not absorb. In France, it accounted for 60% of the total footprint. Some badysts therefore believe that it would be more appropriate to concentrate on this indicator alone.

Conversely, other ecological indicators are not taken into account: the depletion of non-renewable resources (coal, oil, uranium), the erosion of biodiversity, pollution of water, air or soil … Now the degradation of the natural environment, difficult to translate into a single figure, could swell even more the human footprint.

This can the indicator remain relevant?

This figure makes it possible to visualize the evolution of the problem: the ratio computed retroactively since the beginning of the 1970s (with the limits mentioned above) shows that the day of overshooting occurs more and more. earlier in the year. It also highlights the link with economic activity, with a slight decline related to the 2009 crisis.

The data also allow interesting geographic comparisons, which remind us that, beyond the number of inhabitants on earth , the exhaustion of resources is mainly related to their lifestyle: a resident of Qatar will have consumed the equivalent of a year of resources from 9 February and a French 5 May. A Moroccan will be almost at equilibrium, whereas a Zimbabwean will consume in one year only 0.65 of his planetary resources

For environmental NGOs, the figure of the ecological debt has first a pedagogical virtue. "This study uses data that are generally badyzed separately (greenhouse gas emissions and the impacts of our behavior on biodiversity), explains Matthieu Jousset, from the GoodPlanet Foundation. His interest is to adopt a global approach that allows the general public to become familiar with an ecological budget that can not exceed " and better " embody the climate issue ". It is accompanied by a call for action called #movethedate, which calls for reducing food waste (which would save 38 days), halving the number of cars (twelve days), or to make fewer children (thirty days).