System change occurred on an almost unimaginable scale in the natural world, reflecting humankind’s vast and growing dominance of one of our planet’s most vital resources: fresh water.
In what the researchers say is the first global survey of human impacts on the water cycle, scientists have used NASA space measurements to determine changes in the water level found in a staggering number of water bodies: 227,386 of the world’s ponds and lakes. Lockers are either small or large.
While human-managed reservoirs like artificial dams make up only 3.9 percent of this gigantic planetary system of water storage at ground level, this small fraction hides a mind-boggling truth about how much control humankind really exerts over the vagaries of fresh water.
When the total change in water levels across both natural and human-managed systems is calculated, it turns out that human-controlled reservoirs account for 57 percent of all surface water fluctuations – more than half of all tides in freshwater systems.
“We tend to think of the water cycle as a purely natural system: rain and snowmelt flow into rivers, which flow into the ocean where evaporation begins the entire cycle again,” He explains Geophysicist Sarah Cooley of Stanford University.
“But humans actually interfere greatly in that cycle. Our work demonstrates that humans are responsible for the majority of the seasonal changes in surface water storage on Earth.”
The results, drawn from 22 months of data collected by the NASA Ice, Cloud and Earth 2 Satellite (ICESat-2), provide a first-of-its-kind snapshot of water storage worldwide, capturing and measuring small bodies of water. As a football field within the survey.
“Previous satellites were not able to approach this,” Cole saysBut while the scientific achievements are remarkable, junk food is not.
“There are a lot of ways this can be harmful to the environment.”
Risks range from negative impacts on natural ecosystems due to lack of water, to the specter of greenhouse gas emissions Emerging from artificial reservoirs.
Of course, there are other pluses to human-managed reservoirs, too: other than just controlling the water supply, they enable things like hydroelectric systems, while dams can also provide flood protection.
However, the realization that we have assumed control by the majority over something natural like a freshwater tide is a disturbing finding.
Another stark reminder of just how much our species has affected the environment around us – with so great consequences we can only hope to see it from space.
“Of all the changes in volume in bodies of fresh water around the planet – all the floods, droughts and melting ice that push lake levels up and down – humans captured nearly 60 percent of that variation,” Says Ecologist Lawrence Smith from Brown University.
“This has a tremendous effect on the water cycle. In terms of the human influence on the planet, this is directly present with the effects on the land cover and the chemistry of the atmosphere.”
The results are reported in Temperate nature.