But interventions tend to solve water scarcity problems at a local level, while aggravating water scarcity downstream.
In a new study published in the journal Nature Communications, researchers have now assessed the impacts of human interventions on water scarcity at a global scale.
"It’s common sense that taking water out of a river will leave less for those people downstream.
But it’s not so straightforward," says Ted Veldkamp, researcher at Vrije Universiteit Amsterdam and guest researcher at IIASA, who led the study.
Seasonal changes in precipitation and water storage make it difficult for modelers to estimate water availability and impacts of interventions, and the effects of climate change can be difficult to tease out from other impacts like human activities.
This systematic approach allowed the researchers to come up with an estimate that is more realistic than previous approaches — and which also shows greater water scarcity than previous estimates.
From 1971 to 2010, the study found, human impacts have drastically reshuffled water scarcity hotspots, with impacts on approximately one-third of the global population.
On average, approximately 20% of the global population has experienced a significant increase in water availability due to human interventions, such as building water storage, alleviating water scarcity experienced by 8% of the population.
As climate change and population place further pressure on tight water resources, the researchers found that policymakers and water managers need to take a regional and global perspective on local decisions.
This is especially important for transboundary river basins, where policy development in one country may have consequences on different countries downstream.

Wastewater treatment and Sustainable development.
Why in news?
Industrial water consumption accounts for 22% of the global water used, when public awareness of pollution is limited the cost of pollution to our health and the ecosystem is huge.
What is the problem in India?
Traditional wastewater treatment plants may not remove certain pollutants.
The industrial sector in India discharges around 30,730 million cubic metres of effluents, without proper treatment, into water bodies.
Run-off from agriculture fields is another major source of pollution.
What are the water Management strategies?
Market-based strategies such as environmental taxes, pollution levies should be implemented.
The benefits to our health, and in terms of economic development and environmental sustainability, business opportunities and ‘green’ jobs far compensate the costs of wastewater management.

Our impact on water and air answers.
Following are causes of water pollution and the effects it has on human.
Find out more about air and water pollution.
Why Water?
CO2 in air .
Our impact on water and air answers Our impact on water and air answers Our impact on water and air answers Chapter: Our Impact on Water and Air Table of Contents Section 1: Water Pollution.
Following are causes of water pollution and the effects it has on human.
Why Water?
CO2 in air .
25-4-2017 · Why Water ?

The climatic situation has its own impact on the weather variability.
Climate variability is caused both by nature and human activities.
Thirty years ago, climate variability was a phenomena which occurs with a decade-long interval but nowadays it has been a common phenomena to face drought every two years.
At that time, due to lack of coping mechanisms, humans as well as animals used to lose their lives.
In 1985, during the Derg era, though institutionally the Aid Coordinating and Rehabilitation Commission was established in the northern part of the country, one million breathed their last helplessly due to drought.
Currently, in the Horn of Africa, due to drought more than 25 million people are at the verge of lapsing into famine.
Because of this unfolding, they pay less attention to the drought-thorn East African countries.
Their way of life is dominated by pastoral activities and when extreme weather conditions occurs humans and animals face risk.
The scarcity of water turns grazing land into barren ones and the non availability of food-stock and water leave animals to be physically weak and lose their life.
Recently, the government has announced that due to the hungover effect of El Nino and the absence of spring shower, drought has hit the eastern and south-eastern part of the country where particularly the pastoral community dwells and nearly 230 representatives from the Government, UN, NGOs and donors have visited affected communities and the assessment concluded that some 5.6 million people were in need of aid in 2017GC.

Paws without claws?
Effects of carnivore comeback in European anthropogenic landscapes.
In a review article in the Proceedings of the Royal Society B a European research group highlights gaps in knowledge on the effects of carnivores in human-dominated landscapes.
This view is partly based on experiences from Yellowstone National Park.
Although we are not always physically present, these landscapes are still heavily shaped by us, for example, through forestry and hunting."
In other words, humans may remove the claws from the carnivores’ paws.
Perhaps even more important is that the authors suggest that most of the research done so far on the role that predators play in ecosystems has been carried out in landscapes with very low human impact.
"Human activity must be included in research on the ecological effects of large carnivores.
Journal Reference: D. P. J. Kuijper, E. Sahlén, B. Elmhagen, S. Chamaillé-Jammes, H. Sand, K. Lone, J. P. G. M. Cromsigt.
Ecological effects of large carnivores in anthropogenic landscapes.