Lupa Kata Sandi? Klik di Sini

atau Masuk melalui

Belum Memiliki Akun Daftar di Sini


atau Daftar melalui

Sudah Memiliki Akun Masuk di Sini

Konfirmasi Email

Kami telah mengirimkan link aktivasi melalui email ke rudihamdani@gmail.com.

Klik link aktivasi dan dapatkan akses membaca 2 artikel gratis non Laput di koran dan Majalah Tempo

Jika Anda tidak menerima email,
Kirimkan Lagi Sekarang

Study: Global Warming is Shrinking River Vital to 40M People

Translator

Editor

24 February 2017 08:50 WIB

REUTERS/Rick Wilking

TEMPO.CO, Denver - Global warming is already shrinking the Colorado River, the most important waterway in the American Southwest, and it could reduce the flow by more than a third by the end of the century, two scientists say.

The river's volume has dropped more than 19 percent during a drought gripping the region since 2000, and a shortage of rain and snow can account for only about two-thirds of that decline, according to hydrology researchers Brad Udall of Colorado State University and Jonathan Overpeck of the University of Arizona.

In a study published last week in the journal Water Resources Research, they concluded that the rest of the decline is due to a warming atmosphere induced by climate change, which is drawing more moisture out of the Colorado River Basin's waterways, snowbanks, plants and soil by evaporation and other means.

Their projections could signal big problems for cities and farmers across the 246,000-square-mile basin, which spans parts of seven states and Mexico. The river supplies water to about 40 million people and 6,300 square miles of farmland.

"Fifteen years into the 21st century, the emerging reality is that climate change is already depleting the Colorado River water supplies at the upper end of the range suggested by previously published projections," the researchers wrote. "Record-setting temperatures are an important and underappreciated component of the flow reductions now being observed."

The Colorado River and its two major reservoirs, Lake Mead and Lake Powell, are already overtaxed. Water storage at Mead was at 42 percent of capacity Wednesday, and Powell was at 46 percent.

Water managers have said that Mead could drop low enough to trigger cuts next year in water deliveries to Arizona and Nevada, which would be the first states affected by shortages under the multistate agreements and rules governing the system.

But heavy snow in the West this winter may keep the cuts at bay. Snowpack in the Wyoming and Colorado mountains that provide much of the Colorado River's water ranged from 120 to 216 percent of normal Thursday.

For their study, Udall and Overpeck analyzed temperature, precipitation and water volume in the basin from 2000 to 2014 and compared it with historical data, including a 1953-1967 drought. Temperature and precipitation records date to 1896 and river flow records to 1906.

Temperatures in the 2000-2014 period were a record 1.6 degrees Fahrenheit above the historical average, while precipitation was about 4.6 percent below, they said.

Using existing climate models, the researchers said that much decline in precipitation should have produced a reduction of about 11.4 percent in the river flow, not the 19.3 percent that occurred.

They concluded that the rest was due to higher temperatures, which increased evaporation from water and soil, sucked more moisture from snow and sent more water from plant leaves into the atmosphere.

Martin Hoerling, a meteorologist at the National Oceanic and Atmospheric Administration who was not involved in the study, questioned whether the temperature rise from 2000 to 2014 was entirely due to global warming. Some was likely caused by drought, he said.

Udall said warming caused by climate change in this century will dwarf any warming caused by drought. He noted that during the 1953-1967 drought, the temperature was less than a half degree warmer than the historical average, compared with 1.6 degrees during the 2000-2014 period.

Udall said climate scientists can predict temperatures with more certainty than they can precipitation, so studying their individual effects on river flow can help water managers.

Rain and snowfall in the Colorado River Basin would have to increase 14 percent over the historical average through the rest of the century to offset the effect of rising temperatures, he said.

"We can't say with any certainty that precipitation is going to increase and come to our rescue," Udall said.

AP




Elon Musk's SpaceX Sends World's Most Powerful Rocket

12 April 2019

Elon Musk's SpaceX Sends World's Most Powerful Rocket

Elon Musk's SpaceX's Falcon Heavy launched its first commercial mission on Thursday from Florida.


Julian Assange Arrested in London After 7-year Refuge in Embassy

12 April 2019

Julian Assange Arrested in London After 7-year Refuge in Embassy

WikiLeaks founder Julian Assange was arrested by British police on Thursday after Ecuador withdrew its asylum.


Photo of Black Hole Released in Astrophysics Breakthrough

10 April 2019

Photo of Black Hole Released in Astrophysics Breakthrough

The black hole resides about 54 million light-years from Earth.


Facebook Removes Exposed User Data on Amazon's Servers

4 April 2019

Facebook Removes Exposed User Data on Amazon's Servers

Facebook Inc said on Wednesday that it removed public databases containing its user data on Amazon.com Inc's cloud servers.


Nusantara Satu Satellite Succeeds to Orbit above Papua

2 April 2019

Nusantara Satu Satellite Succeeds to Orbit above Papua

Nusantara Satu satellite is successfully put into orbit at 146 degrees east longitude or right above Papua province.


India Shoots Down Satellite in Test

27 Maret 2019

India Shoots Down Satellite in Test

India shot down one of its satellites in space with an anti-satellite missile.


Apple Launches New AirPods before Unveiling Video Service

20 Maret 2019

Apple Launches New AirPods before Unveiling Video Service

Earlier, Apple also launched a new 10.5-inch iPad Air and updated its iPad Mini as well as iMac PCs.


New Zealand Massacre; Users Find Ways to Share Violent Videos

16 Maret 2019

New Zealand Massacre; Users Find Ways to Share Violent Videos

The massacre in Christchurch, New Zealand, was live-streamed by an attacker through his Facebook profile for 17 minutes.


Nusantara Satu Satellite to Provide Internet Across Indonesia

23 Februari 2019

Nusantara Satu Satellite to Provide Internet Across Indonesia

Nusantara Satu satellite will be able to provide internet connection to every village in Indonesia.


SpaceX Rocket Launched Carrying Israel's first Lunar Lander

22 Februari 2019

SpaceX Rocket Launched Carrying Israel's first Lunar Lander

A SpaceX Falcon 9 rocket blasted off from Florida on Thursday night carrying Israel's first lunar lander.