The experts who prepared the report, noted that two key factors are bringing the issue of global thirst: population growth and climate change. And the first question to be addressed is finding a balance between the ratio of the number of living people on the planet and a finite amount of available water reserves.
Top 10 countries where lack of clean water. The ratio of the total population (dotted circle) by the number of people without access to clean water (filled circle)
India recently increased the access to clean water supplies in rural areas, but continues to head the list of countries in terms of population, lacking of water supply. Here is free access to clean water have no more than 163 million people. In second place is Ethiopia. There is a lack of clean water experience of 61 million people. The situation here has improved considerably since the beginning of 2000-ies, however, still a large percentage of local residents lack fresh water.
Without the development of alternative methods and technologies to desalinate sea water in large volumes, the future of humanity will have to rely on the reserves of fresh water, which by that time will remain on the planet.
The main volume of fresh water used in agriculture, mainly for irrigation of agricultural crops, livestock production, and in artificial marine farms for the cultivation of fish and crops used in the food industry. With the growth of the world population will increase and demand for agricultural output, the report said. In recent decades, has slowed the growth of the level of abstraction of freshwater lakes and rivers to ensure rural and industrial farms and settlements, but this figure still outpaces the growth rate of the world's population, established in the 40-ies of the last century.
The volume of water ahead of the growth rate of the world population
This means that very soon every drop of fresh water will be worth its weight in gold. In the end we all have to make very tough decisions on these issues. Populated fields of sugar cane for ethanol production – will not be able to grow food for the family. Build on the river hydroelectric power plant and the people below on the river will not be able to fish. Start to pump groundwater for their own needs, to see us come very unhappy neighbor who waters will not be enough. This is only a small part of the trade-offs that will face mankind. According to scientists, a shortage of fresh water is one of the major problems with which the world must face living in the world of high industrialization and globalization.
"The world is simply not enough water to meet all our needs," says Paolo D Odorico, environmental scientist at the University of California at Berkeley, whose team conducted an analysis of causal relationships between food, water and energy shortages and issued its findings in April of this year in the journal Reviews of Geophysics.
The findings of researchers stated that within the next decades is expected to significantly increase consumption of water and energy sector. While alternative energy sources will not solve the problem, as many may think. Yes, alternative energy will reduce carbon dioxide emissions into the atmosphere, but can hurt in other areas. For example, for growing biofuel crops may need more water than the production and consumption of flammable fuels.
The expected water consumption in the energy sector for the production of various fuels. Under consumption of water supplies refers to the non-renewable sources. The forecast is based, given the stated world powers, obligations phase out of combustible fuels, and taking into account reducing emissions of greenhouse gases in the atmosphere
As mentioned above, the second major factor influencing the loss of fresh water in the world is that of global climate change on the planet. The more greenhouse gases accumulate in our atmosphere, by trapping heat at its surface, the stronger are diminishing reserves of fresh water. The rise in average global temperature leads to changes of weather factors, which in turn leads to a violation of the cyclic water cycle in nature. As a result of environmental disasters (floods, drought, etc.) become more frequent phenomena in our warming planet. Disturbed the ecological balance in areas where people do not need additional water supplies, water is becoming even more and where there is need, it becomes even less.
The map below shows water stress (imbalance between water use and water resources) what Ohm it is expected by 2040. The map built according to "standard" scenario, with the steady growth of carbon dioxide emissions into the atmosphere. Higher water stress is expected in areas where the level of water of the already vulnerable due to the arid climate and population growth.
Water stress countries in the world, projected to 2040
Major cities most strongly feel a shortage of water. Earlier this year, this problem already faced by 4 million residents of Cape town (South Africa). In January, the local government announced that water will only last for 90 days. According to forecasts of the stocks had completely run out in April. Only through a belated and desperate measures aimed at reducing water consumption by the agricultural sector, the residents were able to "hang on" until may when he began a protracted rainy season. The problem of water shortage in the city is not resolved so far. And these cities, according to scientists, in the next 20-30 years will be much more.
By 2050, from 3.5 to 4.4 billion people in the world will have limited access to clean fresh water, with more than 1 billion people of this number are residents of large cities. Among the 482 included in the study of cities and settlements of more than a quarter in the future will face the problem of shortage of fresh water to meet all needs. The main factor influencing the growth of the deficit of fresh water, which is logical, is called: the growth of cities and its population. For example, in the United States in the first place by shortage of water in the future is Los Angeles, because its population is expected to grow despite climate change, which will also reduce its water reserves. In General the water situation in cities will get worse if one of the sectors of their economy will take priority on use of existing stocks, according to the study.
The top 20 cities, according to forecasts, will face major water crisis by 2050
At the sight of such forecasts is very easy to fall into despair. However, scientists remain hopeful and offer alternative options for further development. For example, the results of computer simulations conducted by experts at mit have shown that the choice of political decisions aimed at combating climate change, as it was with the Paris agreement in 2015, will reduce the consequences of pending us shortage of water. If the world community will continue to make such decisions in the future, then, for example, 60 million people in Asia will be able to avoid catastrophic water shortages projected by the year 2050, scientists say.
One of the Paris agreement of course will not be enough. Scientists propose more specific solutions. For example, the experience of Cape town has shown that governments and local city officials need to develop more competent strategies to preserve freshwater supplies. The same increase of water prices to the point at which people would appreciate it more and spend in moderation would reduce the load on its reserves.
"People believe that to solve the problem of water scarcity can only technologiami, but we believe that equally important this issue is to change our own behavior and attitudes," says Martin Floerke, hydrologist and ecologist at the University of Kassel (Germany).
"We need to understand that water is a valuable resource, critical for the operation of the entire global ecosystem, and we need to take care of him. Only in this case we will be able to cope with the problems."