Planet Earth Observations: Decades of Drought on Surface-Waters

Space may be the final frontier

Enlarge / Natural color images from March 1999, April 2005, May 2011, and April 2021 by Landsat satellites chronicle the shrinking Lake Powell reservoir and Lower Colorado River.

 

New NASA satellite to continue half a century of changing Earth observations

"Landsat has provided a critical reference for assessing long-term changes."

Eric Berger - 9/27/2021, 6:33 AM

Hold "A Delta rocket launched the small Earth Resources Technology Satellite in July 1972 with a simple mission: to capture multi-spectral imagery of the planet and assess changes over time.

Data from the polar-orbiting satellite proved so useful that NASA and the US Geological Survey renamed the vehicle Landsat 1 in 1975, and the organizations have since launched a succession of increasingly sophisticated "Landsat" satellites to continue observations. As a result, we now have a nearly half-century-long record of changes to the planet's surface—from farms and forests to glaciers and urban areas.

While the data from the Landsat missions has proved invaluable, it has also been somewhat depressing. The satellites have amassed an impartial record of tropical deforestation in the Amazon, verifying the claims of environmental protection organizations. They have also cataloged increasing water scarcity in the Western United States and chronicled ice losses across the vast majority of Earth's glaciers.

"Landsat has provided a critical reference for assessing long-term changes to Earth's land environment due to both natural and human forcing," scientists concluded in the journal Remote Sensing of Environment, in 2020. . ."

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RELATED CONTENT 2021

First-ever water cuts declared for Colorado River in historic drought

By Rachel Ramirez, CNN

Updated 8:30 AM ET, Tue August 17, 2021

(CNN)The federal government on Monday declared a water shortage on the Colorado River for the first time, triggering mandatory water consumption cuts for states in the Southwest, as climate change-fueled drought pushes the level in Lake Mead to unprecedented lows.

Lake Mead, the largest reservoir in the US by volume, has drained at an alarming rate this year. At around 1,067 feet above sea level and 35% full, the Colorado River reservoir is at its lowest since the lake was filled after the Hoover Dam was completed in the 1930s.

Lake Powell, which is also fed by the Colorado River and is the country's second-largest reservoir, recently sank to a record low and is now 32% full.

"It's very significant," Brad Udall, senior water and climate scientist at Colorado State University, told CNN. "It's something that those of us in the climate community have been worried about for over a decade, based on declining flows due to climate change."

With the lake expected to remain at around 1,066 feet of elevation into 2022, according to the US Bureau of Reclamation's latest monthly projections, the agency announced that the Colorado River will go into the first tier of water cuts beginning January 1.

Read More

"Given ongoing historic drought and low runoff conditions in the Colorado River Basin, downstream releases from Glen Canyon Dam and Hoover Dam will be reduced in 2022 due to declining reservoir levels," the report said.

Lake Mead provides water to roughly 25 million people in Arizona, Nevada, California and Mexico, according to the National Park Service. Under the complex priority system, Arizona and Nevada will be affected by the tier-1 shortage.

Arizona will see an 18% reduction in the state's total Colorado River supply, primarily impacting agriculture. Although Nevada will need to adhere to a 7% reduction in its Colorado River water supply in 2022, the state had already reduced its deliveries and no change is expected due to the shortage, according to John Entsminger, general manager of the Southern Nevada Water Authority.

Additional cuts -- each tier with worsening impact on agriculture and municipal water -- are expected if Lake Mead continues to fall. The second tier of cuts, triggered at 1,050 feet, could come as soon as 2023.

More than 95% of the West was in drought as of last week, the largest area in the history of the US Drought Monitor

First-ever water cuts declared for Colorado River in historic drought

By Rachel Ramirez, CNN

Updated 8:30 AM ET, Tue August 17, 2021

 

The climate crisis is taking these farmers' most valuable resource

(CNN)The federal government on Monday declared a water shortage on the Colorado River for the first time, triggering mandatory water consumption cuts for states in the Southwest, as climate change-fueled drought pushes the level in Lake Mead to unprecedented lows.

Lake Mead, the largest reservoir in the US by volume, has drained at an alarming rate this year. At around 1,067 feet above sea level and 35% full, the Colorado River reservoir is at its lowest since the lake was filled after the Hoover Dam was completed in the 1930s.

Lake Powell, which is also fed by the Colorado River and is the country's second-largest reservoir, recently sank to a record low and is now 32% full.

"It's very significant," Brad Udall, senior water and climate scientist at Colorado State University, told CNN. "It's something that those of us in the climate community have been worried about for over a decade, based on declining flows due to climate change."

 

With the lake expected to remain at around 1,066 feet of elevation into 2022, according to the US Bureau of Reclamation's latest monthly projections, the agency announced that the Colorado River will go into the first tier of water cuts beginning January 1.

Read More

"Given ongoing historic drought and low runoff conditions in the Colorado River Basin, downstream releases from Glen Canyon Dam and Hoover Dam will be reduced in 2022 due to declining reservoir levels," the report said.

Lake Mead provides water to roughly 25 million people in Arizona, Nevada, California and Mexico, according to the National Park Service. Under the complex priority system, Arizona and Nevada will be affected by the tier-1 shortage.

Arizona will see an 18% reduction in the state's total Colorado River supply, primarily impacting agriculture. Although Nevada will need to adhere to a 7% reduction in its Colorado River water supply in 2022, the state had already reduced its deliveries and no change is expected due to the shortage, according to John Entsminger, general manager of the Southern Nevada Water Authority.

Additional cuts -- each tier with worsening impact on agriculture and municipal water -- are expected if Lake Mead continues to fall. The second tier of cuts, triggered at 1,050 feet, could come as soon as 2023.

 

Google Earth Timelapse (Google, Landsat, Copernicus)

Snaking its way through the Rocky Mountains to the Gulf of California, the Colorado River's volume have been dwindling due to extreme heat and drought.

T.J. Atkin, a cattle rancher in Utah and Arizona, described the toll the drought was taking on his family's business and his animals.

"Everyone else I've talked to says in 85 years, it has not been this bad," Atkin told CNN in June. "We have 85 years' worth of our own drought data that says we've never done this ... not to this extent."

At a news conference announcing the cuts, US officials said climate change is behind the West's water shortage.

A UN report released last week emphasized the role human-caused climate change plays in drought frequency and intensity. Globally, droughts that may have occurred only once every 10 years or so now happen 70% more frequently, according to the report. The link is particularly strong in the Western US, scientists said, which is currently in the grips of a historic, multi-year drought.

More than 95% of the West was in drought as of last week, the largest area in the history of the US Drought Monitor.

"There's no doubt that climate change is real -- we're experiencing it every day in the Colorado River Basin and in other basins in the West," said Tanya Trujillo, assistant secretary for water and science at the US Department of the Interior. "I think the best strategy for planning is to think about a broad range of scenarios and a broad range of potential hydrology, and to work closely with our partners in the basin to try to think through all of those scenarios."

Photos: The West's historic drought

Low water levels can be seen in the Hoover Dam reservoir of Lake Mead on June 9. Water levels at Lake Powell and Lake Mead -- the two largest reservoirs on the Colorado River -- have dropped at an alarming rate.

On average, the Colorado River's flow has declined by about 20% over the last century, according to a 2020 study by US Geological Survey scientists. Over half of that decline can be attributed to warming temperatures across the basin, researchers said.

Without any significant reductions to planet-heating emissions, particularly from the burning of fossil fuels, the study found the Colorado River's average discharge could shrink by 31%, compared to the historical average, by the middle of this century -- a theme consistent with the UN climate report.

The significance of the reservoirs' rapid decline cannot be overstated. The Colorado River supplies water to more than 40 million people living across seven US states and Mexico.

Lake Mead and Lake Powell provide a critical supply of drinking water, hydropower and irrigation for many communities across the region including rural farms and tribal nations.

 

As the climate rapidly changes, Udall said the West should prepare for more shortages.

"Climate change is water change, and many of the worst impacts we're going to see out of climate change are through changes in the water cycle," Udall said. "Not only do we have to plan for these undesirable water outcomes, but we also have to get our act together and reduce greenhouse gases as fast as we can."

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Lake Mead, Arizona – Nevada

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Uploaded by: Google Earth, Apr 25, 2019

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Earth Timelapse is a global, zoomable time-lapse video of the entire planet, from 1984 to now. Explore this location at: https://g.co/earthtimelapse/#v=36.07...

 

 

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Biz & IT —

How Google built a 52-terapixel time-lapse portrait of Earth

30-meter-per-pixel video of entire planet.

Sean Gallagher - 6/10/2013, 9:10 AM

A frame of Timelapse's view of the growth of Las Vegas, Nevada.

>> The report continues ". . .Over 40 years of NASA satellite data has been "ingested into Earth engine," said Sargent. "That's been married to Google's compute infrastructure, so you can detect deforestation or find land use changes."

 

Sargent and the Earth Engine team used 909 terabytes of data from the Landsat 4, 5, and 7 satellites—with each of the million images weighing in at more than 100 megapixels.

Landsat's polar orbit allows each satellite to take a full set of images of the Earth's surface every 16 days. But not all of those images are keepers due to weather and other factors. "It's not as easy as just lining up the pixels," Sargent said. "Most of the challenges involved dealing with the atmosphere—if it's cloudy, you're not seeing anything. And if it's hazy, you have to look through it. So we had to build mosaics that excluded cloudy images and then correct for haze." . .

Time Machine ingests very high-resolution videos and converts them into multiple overlapping multi-resolution video tiles delivered as a stream, using a manipulation of HTML5's video tag in a way similar to how Google uses HTML image tags to pan and zoom in Google Maps.

Previous Time Machine projects had handled videos with billions of pixels of resolution. But Time-Lapse Earth pushed the envelope for Time Machine because of the size of the data. The 30-meter-per-pixel video was generated from 29 Mercator-projected mosaics created by Earth Engine, and each frame had 1.78 trillion pixels.