Beginning of sorrows; Record low water levels on the Mississippi River in 2022 show how climate change is altering the world’s large rivers
Ray Lombardi, Assistant Professor of Earth Sciences, University of Memphis, Dorian J. Burnette, Associate Professor of Atmospheric Science, University of Memphis, and Angela Antipova, Associate Professor of Earth Sciences, University of Memphis
Tue, January 10, 2023 at 4:03 PM EST
Rivers are critical corridors that connect cities and ecosystems alike. When drought develops, water levels fall, making river navigation harder and more expensive.
In 2022, water levels in some of the world’s largest rivers, including the Rhine in Europe and the Yangtze in China, fell to historically low levels. The Mississippi River fell so low in Memphis, Tennessee, in mid-October that barges were unable to float, requiring dredging and special water releases from upstream reservoirs to keep channels navigable.
Conditions on the lower Mississippi may be easing somewhat, thanks to early winter rains. But as Earth scientists at the University of Memphis, we see this year’s dramatic plunge in water levels as a preview of a climate-altered future.
River barges are an efficient way to transport bulk commodities, such as grain shipments, and heavy equipment over long distances. But that’s true only for normal water conditions. Increased swings between extreme lows and highs on the Mississippi River, driven by climate change, mean that typical water conditions are no longer the norm, and that river transport is likely to face more backups in the future.
A huge decrease in volume
Droughts tend to begin when precipitation drops below normal levels. Many other factors, including temperature, wind, cloudiness and soil type in the region, influence how severe droughts become. Soil can hold water from previous months of precipitation, providing flow to rivers that delays the onset of declines downstream.
In Memphis, hot, dry weather developed in late June 2022 and continued into the early fall. Hotter temperatures increased evaporation rates and decreased soil moisture, creating a flash drought – one that developed within weeks.
The Mississippi River’s watershed drains an area that covers 1.2 million square miles (3.2 million square kilometers) – more than 40% of the continental U.S. This produces a huge flow, especially on the lower Mississippi as more tributaries empty into it.
When water levels are normal, more than 500,000 cubic feet (14,000 cubic meters) flow past Memphis every second. That’s enough to fill the Rose Bowl stadium in Pasadena, California, in less than a minute.
Stream flow in the lower Mississippi can be slow to respond to changes in precipitation, since water must travel long distances to reach the region. During the recent flash drought, however, water levels in the river declined sharply from August into October, reaching a historic low on Oct. 20, 2022, at Memphis. The river fell by 20 feet over 11 weeks.
Changing flash drought patterns
The 2022 flash drought occurred within a long-term trend in which annual minimum water levels on the lower Mississippi River have declined over the past century. In other words, yearly lows are getting lower.
There are two primary causes for these extreme lows. First, construction of locks, dams and levees for flood management starting in the 1930s has impounded a growing share of the river’s flow upstream and decreased variations in the river’s flow. This has unintentionally made low-water events more severe.
Second, the 2022 flash drought affected different areas than previous extreme low-water events. In past years, hot and dry flash drought weather was centered over tributaries of the Missouri and Ohio rivers, which flow into the Mississippi. This caused less water to reach the lower Mississippi River. In 2022 soil moisture levels were normal in the tributaries, but a flash drought developed in the central U.S. over the Mississippi River itself, increasing evaporation and reducing lower Mississippi River water levels.
The idea that the main stem of a large river like the Mississippi can experience low water even when its major tributaries are flowing at normal levels goes against conventional thinking about hydrologic drought. This year’s historic event in the Mississippi River watershed is evidence that climate change is altering large rivers as high temperatures increase evaporation and make soil more “thirsty.”
The Mississippi River is a key waterway for moving grain by barge from farm states to domestic and export markets. Barges are the least expensive and most sustainable option for commercial shipping.
A single hopper barge can carry as much dry cargo as 16 rail cars or 70 trucks. About 92% of U.S. agricultural exports, including soybeans, corn and wheat, move through the Mississippi River Basin.
Low water levels reduce the navigable portions of the river that are deep enough for barges. On Oct. 7, 2022, over 2,000 barges were backed up at various points along the Mississippi because of river closures. Low water levels disrupted shipments both north and south.
Shipping costs rise during harvest season, when demand for barge transportation is higher. Barge rates can fluctuate significantly depending on market supply and demand, the size of the barge fleet and other factors.
Navigation restrictions on the Mississippi due to low water levels have steeply increased the weekly cost of transporting grain by barge. The average rate of shipping by barge skyrocketed from around US- per ton in the summer of 2022 to over per ton in October 2022. In November it declined to an average of .25 per ton – still more than double the typical rate.
Preparing for more water lows
Warmer atmospheric temperatures have the potential to evaporate more water, causing drought, and to hold more water, causing extreme rainfall. Prehistoric river records in North America indicate that warmer temperatures 1,000 years ago made precipitation patterns more variable, with significant droughts punctuated by extreme floods – conditions similar to those we are seeing now on the lower Mississippi.
Over the past 100 years, year-to-year changes from very dry to very wet in the Mississippi River Valley have become more frequent. We expect this trend to continue as global temperatures continue to rise because of climate change.
Companies that ship grain will search for shipping alternatives, and repeated dredging may be necessary to keep the river navigable. This will make shipping more expensive, with higher costs passed on to consumers.
Low water levels on the river also allow salt water to creep north from the Gulf of Mexico, which could contaminate drinking water supplies in southern Louisiana. To prevent this, the Army Corps of Engineers is building an underwater levee to block salt water, which is denser and sinks below fresh water, from moving upstream.
Through the 20th century, river engineering on the Mississippi was driven by the need to reduce flooding. Flood mitigation will still be important in the future, but the risk of low-water events will also increase. As the U.S. enters a new era of hydrologic extremes, we believe it is critical to understand how watersheds and large rivers respond to climate change, so that industries and communities can better prepare for the future.
This article has been updated to correct the value provided for the volume of water that flows past Memphis every second.
This article is republished from The Conversation, a nonprofit news site dedicated to sharing ideas from academic experts. If you found it interesting, you could subscribe to our weekly newsletter.
It was written by: Ray Lombardi, University of Memphis; Angela Antipova, University of Memphis, and Dorian J. Burnette, University of Memphis.
Looking back on America’s summer of heat, floods and climate change: Welcome to the new abnormal
As flood risks increase across the US, it’s time to recognize the limits of levees
What is a flash drought? An earth scientist explains
Ray Lombardi receives funding from USGS.
Dorian J. Burnette receives funding from the National Science Foundation and from the Tennessee Department of Transporation.
Angela Antipova does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
But how can they call on him (Jesus Christ) to save them unless they believe in him (Jesus Christ)? And how can they believe in him (Jesus Christ) if they have never heard about him (Jesus Christ)? And how can they hear about him (Jesus Christ) unless someone tells them?” —Romans 10:14
In His Service,
Night Watchman Ministries
Make Your Decision for Christ NOW!!!!!!! Time is Up!!!!!!!
Jesus Christ’s Offer of Salvation:
The ABCs of Salvation through Jesus Christ (the Lamb)
A. Admit/Acknowledge/Accept that you are sinner. Ask God’s forgiveness and repent of your sins.
. . . “For all have sinned, and come short of the glory of God.” (Romans 3:23).
. . . “As it is written, There is none righteous, no, not one.” (Romans 3:10).
. . . “If we say that we have no sin, we deceive ourselves, and the truth is not in us.” (1 John 1:8).
B. Believe Jesus is Lord. Believe that Jesus Christ is who He claimed to be; that He was both fully God and fully man and that we are saved through His death, burial, and resurrection. Put your trust in Him as your only hope of salvation. Become a son or daughter of God by receiving Christ.
. . . “That whosoever believeth in him should not perish, but have eternal life. For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life. For God sent not his son into the world to condemn the world; but that the world through him might be saved. (John 3:15-17). For whosoever shall call upon the name of the Lord shall be saved.” (Romans 10:13).
C. Call upon His name, Confess with your heart and with your lips that Jesus is your Lord and Savior.
. . . “That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved. For with the heart man believeth unto righteousness; and with the mouth confession is made unto salvation.” (Romans 10:9-10).
. . . “If we say that we have no sin, we deceive ourselves, and the truth is not in us. If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness. If we say that we have not sinned, we make him a liar, and his word is not in us.” (John 1:8-10).
. . . “And he is the propitiation for our sins: and not for ours only, but also for the sins of the whole world. (John 2:2).
. . . “In this was manifested the love of god toward us, because that God sent his only begotten Son into the world, that we might live through him. And we have seen and do testify that the Father sent the Son to be the Saviour of the world. Whosoever shall confess that Jesus is the Son of God, God dwelleth in him, and he in God.” (1 John 4:9, 14-15).
. . . “But God commendeth his love toward us, in that, while we were yet sinners, Christ died for us. Much more then, being now justified by his blood, we shall be saved from wrath through him. For if, when we were enemies, we were reconciled to God by the death of his Son, much more, being reconciled, we shall be saved by his life.” (Romans 5:8-10).
. . . “For the wages of sin is death; but the gift of God is eternal life through Jesus Christ our Lord.” (Romans 6:23).
. . . “Jesus saith unto them, I am the way, the truth, and the life, no man cometh unto the Father, but by me.” (John 14:6).
. . . “For I am not ashamed of the gospel of Christ: for it is the power of God unto salvation to everyone that believeth.” (Romans 1:16).
. . . “Neither is there salvation in any other: for there is none other name under heaven given among men, whereby we must be saved.” (Acts: 4:12).
. . . “Who will have all men to be saved, and to come unto the knowledge of the truth for there is one God, and one mediator between God and men, the man Christ Jesus.” (1 Timothy 2:4-6).
. . . “For God did not appoint us to suffer wrath but to receive salvation through our Lord Jesus Christ.” (1 Thessalonians 5:9).
. . . “But as many as received him, to them gave the power to become the sons of God, even to them that believe on his name.” (John 1:12).
True Church / Bride of Christ Spared from God’s Wrath:
Romans 5:8-10. “But God commendeth his love toward us, in that, while we were yet sinners, Christ died for us. Much more then, being now justified by his blood, we shall be saved from wrath through him. For if, when we were enemies, we were reconciled to God by the death of his Son, much more, being reconciled, we shall be saved by his life.”
Romans 12:19. Dearly beloved, avenge not yourselves, but rather give place unto wrath: for it is written, Vengeance is mine; I will repay, saith the Lord.
1 Thessalonians 1:10. And to wait for his Son from heaven, whom he raised from the dead, even Jesus, which delivered us from the wrath to come.
1 Thessalonians 5:9. For God hath not appointed us to wrath, but to obtain salvation by our Lord Jesus Christ,
Romans 8:35. Who shall separate us from the love of Christ? shall tribulation, or distress, or persecution, or famine, or nakedness, or peril, or sword?
Jeremiah 30:7. Alas! for that day is great, so that none is like it: it is even the time of Jacob’s trouble, but he shall be saved out of it.
Revelation 3:10 Because thou hast kept the word of my patience, I also will keep thee from the hour of temptation, which shall come upon all the world, to try them that dwell upon the earth.
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