SHARING. This Monday, March 19, 2018 opens in Brasilia ( Brazil ) an 8 e World Water Forum that proves strategic. Titled "the sharing of water", this triennial meeting takes place just before two crucial meetings: the political forum next July (it will gather in New York most of the leaders on the objectives of access to the drinking water and sanitation by 2030) and December COP 24 in Poland on the climate where water appears as a priority in 93% of national contributions to the fight against global warming . This is the moment also chosen by Unesco to publish its world report 2018 . This sum of data gives an idea of the challenges facing humanity.
World water consumption increases by 1% per year
Men currently harvest 4600 billion m 3 d water per year. Domestic use accounts for 10% against 60% for agriculture and 30% for industry. This world consumption increases by 1% per year and should reach 6000 billion m 3 per year in 2050. But access to the resource should undergo major upheavals. First, the increase in the population will increase the needs of agriculture, particularly in groundwater, which is more difficult to renew. 800 billion m 3 are now collected in the groundwater. Excessive pumping could lead to severe shortages in already stressed areas. The management of domestic water will be impacted by the growth of cities, 66% of men living in urban areas in 2050 against 54% today.
In red, areas where water shortages are already noted . The impacted areas will be more extensive in 2050, particularly in India and China. © Unesco.
80% of industrial and municipal wastewater discharged into rivers without treatment
" The deterioration of water quality is expected to intensify over the next few years decades, which would increase threats to human health, the environment and development "says Unesco citing a report of the multinational Veolia. Currently 80% of all industrial and municipal wastewater is discharged into rivers without any prior treatment. Agriculture remains the main source of nitrate increases in the natural environment and the use of chemical pesticides increases by about 2 million tonnes per year. In Europe, where the situation is much more favorable than in the rest of the world, 30% of the rivers and 40% of the lakes harbor too much phosphorus.
The evolution of the quality of water in the world. The situation is worsening mainly in East Africa, India and China. © Unesco
If the participants of the Brasilia Forum are preparing for the climate change negotiations (COP24) at the end of 2018 in Poland, it is because the issue of water is central for many states on at least two plans: rising temperatures are disrupting water availability and global warming will disrupt the water cycle and increase droughts and floods. Already, 1.8 billion people live in regions affected by desertification and drought, making it the most serious "natural disaster" for humanity. Floods have affected 2.3 billion people since 1995. Between 2005 and 2014, there was an average of 171 floods per year compared with 127 in the previous decade.
Focusing "green" infrastructures on infrastructure " "
It is these new and distressing situations that are studied throughout the week in Brasilia. With, however, reasons for hope. First, there is enough fresh water on the planet to water 10 billion people. Then, management techniques (rational irrigation, water distribution, savings in industry) exist and can be deployed quickly. Finally, the preservation of the quality of the resource uses simple and inexpensive techniques. It is on this aspect that Unesco emphasizes. " There will always be need to build dikes, to make pipes and purification plants, statue and Richard Connor, editor-in-chief of the report of Unesco. But next to these "gray" infrastructures, we have a whole panoply of "green" infrastructures relying on the ecological engineering and the use of the role played by the ecosystems "
The protection of the catchment areas of its drinking water This allows New York City to save 25 million euros a year in the cost of potabilization. In Madagascar, the "intensification system of rice" which favors a better management of water and soil has saved 25 to 50% of water and 80% of seeds while increasing the production of 25 to 50%. " Worldwide, it is estimated that agricultural production could increase by almost 20% thanks to greener practices of water management ," says Richard Connor. The margin of progress is immense. According to a report cited by UNESCO on agricultural development projects in 57 low-income countries, more efficient use of water and improved plant cover, particularly through agroforestry, have improved agricultural yields. 79% without increasing the use of pesticides