question: How does the water level on Earth keep getting replenished? And how come the water levels are rising despite the wide scale consumption by humans and animals and plants?
comment: The water doesn’t get replenished, it’s just never used up. It never leaves the planet. It’s just a cycle. The water levels are rising because the ice caps are melting.
passages: The increase in the world population and the increase in per capita water use puts increasing strains on the finite resources availability of clean fresh water. The World Bank adds that the response by freshwater ecosystems to a changing climate can be described in terms of three interrelated components: water quality, water quantity or volume, and water timing. A change in one often leads to shifts in the others as well. Water pollution and subsequent eutrophication also reduces the availability of fresh water.
   The amount of available freshwater supply in some regions is decreasing because of (i) climate change, which has caused receding glaciers, reduced stream and river flow, and shrinking lakes; (ii) contamination of water by human and industrial wastes; and (iii) overuse of non-renewable groundwater aquifers. Many aquifers have been over-pumped and are not recharging quickly. Although the total freshwater supply is not used up, much has become polluted, salted, unsuitable or otherwise unavailable for drinking, industry, and agriculture.
  
  Section::::Water demand.
   When global warming is added into the equation, changes occur, especially in the regions where deep water is formed. With the warming of the oceans and subsequent melting of glaciers and the polar ice caps, more and more fresh water is released into the high latitude regions where deep water is formed. This extra water that gets thrown into the chemical mix dilutes the contents of the water arriving from lower latitudes, reducing the density of the surface water. Consequently, the water sinks more slowly than it normally would.
   Fifty years ago, the common perception was that water was an infinite resource. At the time, there were fewer than half the current number of people on the planet. People were not as wealthy as today, consumed fewer calories and ate less meat, so less water was needed to produce their food. They required a third of the volume of water we presently take from rivers. Today, the competition for the fixed amount of water resources is much more intense, giving rise to the concept of peak water. This is because there are now nearly seven billion people on the planet, their consumption of water-thirsty meat and vegetables is rising, and there is increasing competition for water from industry, urbanisation and biofuel crops. In future, even more water will be needed to produce food because the Earth's population is forecast to rise to 9 billion by 2050.
   Global changes caused largely by anthropogenic influences, or human impacts, are altering the amount of freshwater inflows to estuaries. Humans are diverting water from rivers and streams, decreasing the amount of flows making it to estuarine ecosystems. Since the 1960s dewatering, or removal of water from streams and rivers, has doubled and around 60% of the Earth’s runoff is captured. The removal of freshwater from rivers and streams for anthropogenic use before it reaches the coast is having a negative impact on many estuaries. Half of the world’s major cities are within 50 km of the coast, and coastal populations are 2.6 times denser than those further inland. Technological advances in the collection of freshwater is continually improving, further straining available freshwater resources. As the human population grows and the strain on water resources continues, the ability to effectively manage freshwater inflows into estuaries is becoming a priority worldwide.
   Fresh water is a renewable resource, yet the world's supply of clean, fresh water is under increasing demand for human activities. The world has an estimated 1.34 billion cubic kilometers of water, but 96.5% of it is salty. Almost 70% of fresh water can be found in the ice caps of Antarctica and Greenland. Less than 1% of this water on Earth is accessible to humans, the rest is contained in soil moisture or deep underground. Accessible freshwater is located in lakes, rivers, reservoirs and shallow underground sources. Rainwater and snowfall do very little to replenish many underground sources.
   Humans impact how much water is stored on land. Building dams prevents large masses of water from flowing into the sea and therefore increases the storage of water on land. On the other hand, humans extract water from lakes, wetlands and underground reservoirs for food production leading to rising seas. Furthermore, the hydrological cycle is influenced by climate change and deforestation, which can lead to further positive and negative contributions to sea level rise. In the 20th century, these processes roughly balanced, but dam building has slowed down and is expected to stay low for the 21st century.
  
  Section::::Projections.
   The available fresh water being affected by the climate is also being stretched across an ever-increasing global population. It is estimated that almost a quarter of the global population is living in an area that is using more than 20% of their renewable water supply; water use will rise with population while the water supply is also being aggravated by decreases in streamflow and groundwater caused by climate change. Even though some areas may see an increase in freshwater supply from an uneven distribution of precipitation increase, an increased use of water supply is expected.
   "Specific water availability is the residual (after use) per capita quantity of fresh water." Fresh water resources are unevenly distributed in terms of space and time and can go from floods to water shortages within months in the same area. In 1998 76% of the total population had a specific water availability of less than 5.0 thousand m³ per year per capita. Already by 1998, 35% of the global population suffered "very low or catastrophically low water supplies" and Shiklomanov predicted that the situation would deteriorate in the twenty-first century with "most of the Earth's population will be living under the conditions of low or catastrophically low water supply" by 2025. There is only 2.5% of fresh water in the hydrosphere and only 0.25% of water is accessible for our use.
   Another popular opinion is that the amount of available freshwater is decreasing because of climate change. Climate change has caused receding glaciers, reduced stream and river flow, and shrinking lakes and ponds. Many aquifers have been over-pumped and are not recharging quickly. Although the total fresh water supply is not used up, much has become polluted, salted, unsuitable or otherwise unavailable for drinking, industry and agriculture. To avoid a global water crisis, farmers will have to strive to increase productivity to meet growing demands for food, while industry and cities find ways to use water more efficiently.
   On August 30, 2012, Bulcke was quoted as saying: "If something isn't given a value, people tend to waste it. Water is our most useful resource, but those using it often don’t even cover the costs of its infrastructure. Fresh water is being massively overused at nature's expense, but it seems only a global crisis will make us realise the importance of the issue. What is environmentally unsustainable today will become socially unsustainable in the future."
  
  Section::::Awards and honours.
   Water used for agriculture is called "agricultural water" or "farm water." Changing landscape for the use of agriculture has a great effect on the flow of fresh water. Changes in landscape by the removal of trees and soils changes the flow of fresh water in the local environment and also affects the cycle of fresh water. As a result, more fresh water is stored in the soil which benefits agriculture. However, since agriculture is the human activity that consumes the most fresh water, this can put a severe strain on local freshwater resources resulting in the destruction of local ecosystems.
   Around fifty years ago, the common perception was that water was an infinite resource. At that time, there were fewer than half the current number of people on the planet. People were not as wealthy as today, consumed fewer calories and ate less meat, so less water was needed to produce their food. They required a third of the volume of water we presently take from rivers. Today, the competition for water resources is much more intense. This is because there are now seven billion people on the planet, their consumption of water-thirsty meat and vegetables is rising, and there is increasing competition for water from industry, urbanisation biofuel crops, and water reliant food items. In the future, even more water will be needed to produce food because the Earth's population is forecast to rise to 9 billion by 2050. An additional 2.5 or 3 billion people, choosing to eat fewer cereals and more meat and vegetables could add an additional five million kilometres to the virtual canal mentioned above.
   Section::::Views.:Population.
  
  In March 2012 expressed concern about rising population and falling water levels in Arab countries. He noted that populations had risen by an average of 1.7 percent a year (compared with the global average of 1.2 percent) while water available had dropped 75 percent since 1950. "Less water means no crops - so it's a perfect storm."
  
  "I think the tipping point has been reached," Geldof said. "There can't be more people on the Earth than we can feed."
   An increased population means increased withdrawals from the water supply for domestic, agricultural, and industrial uses, the largest of these being agriculture, believed to be the major non-climate driver of environmental change and water deterioration. The next 50 years will likely be the last period of rapid agricultural expansion, but the larger and wealthier population over this time will demand more agriculture.
   Water demand already exceeds supply in many parts of the world, and as the world population continues to rise, many more areas are expected to experience this imbalance in the near future.
  
  Agriculture represents 70% of freshwater use worldwide.
  
  Agriculture, industrialization and urbanization all serve to increase water consumption.
  
  Section::::Freshwater withdrawal by country.
  
  The largest total use of water comes from India, China and the United States, countries with large populations, extensive agricultural irrigation, and demand for food. See the following table:
  
  Section::::Freshwater withdrawal by country.:India.
   Water covers 71% of the Earth's surface. Of this, 97.5% is the salty water of the oceans and only 2.5% freshwater, most of which is locked up in the Antarctic ice sheet. The remaining freshwater is found in glaciers, lakes, rivers, wetlands, the soil, aquifers and atmosphere. Due to the water cycle, fresh water supply is continually replenished by precipitation, however there is still a limited amount necessitating management of this resource. Awareness of the global importance of preserving water for ecosystem services has only recently emerged as, during the 20th century, more than half the world's wetlands have been lost along with their valuable environmental services. Increasing urbanization pollutes clean water supplies and much of the world still does not have access to clean, safe water. Greater emphasis is now being placed on the improved management of blue (harvestable) and green (soil water available for plant use) water, and this applies at all scales of water management.
   Climate change, rising atmospheric carbon dioxide, excess nutrients, and pollution in many forms are altering global oceanic geochemistry. Rates of change for some aspects greatly exceed those in the historical and recent geological record. Major trends include an increasing acidity, reduced subsurface oxygen in both near-shore and pelagic waters, rising coastal nitrogen levels, and widespread increases in mercury and persistent organic pollutants. Most of these perturbations are tied either directly or indirectly to human fossil fuel combustion, fertilizer, and industrial activity. Concentrations are projected to grow in coming decades, with negative impacts on ocean biota and other marine resources.
   Through the last hundred years, more than half of the Earth's wetlands have been destroyed and have disappeared. These wetlands are important not only because they are the habitats of numerous inhabitants such as mammals, birds, fish, amphibians, and invertebrates, but they support the growing of rice and other food crops as well as provide water filtration and protection from storms and flooding. Freshwater lakes such as the Aral Sea in central Asia have also suffered. Once the fourth largest freshwater lake, it has lost more than 58,000 square km of area and vastly increased in salt concentration over the span of three decades.
   In the 15-year period 1995–2010 alone, acidity has increased 6 percent in the upper 100 meters of the Pacific Ocean from Hawaii to Alaska. According to a statement in July 2012 by Jane Lubchenco, head of the U.S. National Oceanic and Atmospheric Administration "surface waters are changing much more rapidly than initial calculations have suggested. It's yet another reason to be very seriously concerned about the amount of carbon dioxide that is in the atmosphere now and the additional amount we continue to put out."
   Fresh water is a renewable and variable, but finite natural resource. Fresh water can only be replenished through the process of the water cycle,in which water from seas, lakes, forests, land, rivers, and reservoirs evaporates, forms clouds, and returns as precipitation. Locally, however, if more fresh water is consumed through human activities than is naturally restored, this may result in reduced fresh water availability from surface and underground sources and can cause serious damage to surrounding and associated environments.
  
  Fresh and unpolluted water accounts for 0.003% of total water available globally.
   David Pimentel, professor of ecology and agriculture at Cornell University, estimates that the sustainable agricultural carrying capacity for the United States is about 200 million people; its population as of 2015 is over 300 million. In 2009, the UK government's chief scientific advisor, Professor John Beddington, warned that growing populations, falling energy reserves and food shortages would create a "perfect storm" of shortages of food, water, and energy by 2030. According to a 2009 report by the United Nations Food and Agriculture Organization (FAO), the world will have to produce 70% more food by 2050 to feed a projected extra 2.3 billion people.
   The UN's Food and Agriculture Organization (FAO) released their biennial State of World Fisheries and Aquaculture in 2018 noting that capture fishery production has remained constant for the last two decades but unsustainable overfishing has increased to 33% of the world's fisheries. They also noted that aquaculture, the production of farmed fish, has increased from 120 million tonnes per year in 1990 to over 170 million tonnes in 2018.
  
  Section::::Fishing and Farming.:Irrigation.
   Section::::Dangers and effects.:Depletion and destruction of resources.:Fresh water.
  
  Overpopulation may lead to inadequate fresh water for drinking as well as sewage treatment and effluent discharge. Some countries, like Saudi Arabia, use energy-expensive desalination to solve the problem of water shortages.
  
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  Fresh water supplies, on which agriculture depends, are running low worldwide. This water crisis is only expected to worsen as the population increases.
  
  Potential problems with dependence on desalination are reviewed below, however, the majority of the world's freshwater supply is contained in the polar icecaps, and underground river systems accessible through springs and wells.
   One major component of environmental degradation is the depletion of the resource of fresh water on Earth. Approximately only 2.5% of all of the water on Earth is fresh water, with the rest being salt water. 69% of fresh water is frozen in ice caps located on Antarctica and Greenland, so only 30% of the 2.5% of fresh water 
  
presuppositions: The water level on Earth gets replenished. Water on Earth keeps getting replenished. 
corrections: The water is never used up, it doesn't get replenished. Water on Earth isn't replenished but never leaves the planet.
raw_presuppositions: The water level on Earth gets replenished. Water on Earth keeps getting replenished. 
raw_corrections: The water is never used up, it doesn't get replenished. Water on Earth isn't replenished but never leaves the planet.