As levels continue to drop along a long stretch of the Mississippi River in the coming weeks, the risk of grounding incidents will increase. (Photos.com image)

The ongoing drought has river levels along the Mississippi River plunging to very low levels this summer and could stall barge traffic in some areas into the autumn if rainfall does not come soon.

It was just last year when levels along the Mississippi River and many of its tributaries were close to record high levels. What a difference a year makes.

Falling river levels are not uncommon during the summer months in the central and eastern United States. However, the building drought over much of the middle of the nation currently has the mighty Mississippi running well below normal and levels in many areas are likely to fall through much of the summer, unless widespread rain comes.

River levels along stretches of the Mississippi were already beginning to cause minor problems below the Ohio River junction.

Very low water levels expose shoals, potentially putting river traffic at risk for getting stuck in the mud.

Sandbars have been exposed at Vicksburg, Miss.

Officials in some areas are considering one-way traffic along portions of Old Man River.

According to National Weather Service (NWS) Hydrologists river levels along parts of the Mississippi River are 30 to 50 feet lower this year, compared to around the same time last year.

While significant rain is forecast to fall by AccuWeather.com over portions of the Ohio and Tennessee river tributaries and in part of the Mississippi Delta in the coming weeks, a lack of rain will continue over the Arkansas, Missouri and Upper Mississippi rivers for much of the summer.

Barge traffic from near Cairo, Ill. to St. Louis could potentially be impacted, if river levels get much lower due to the lack of rain in areas north and west of the intersection of the Ohio and Mississippi rivers.

According to NWS Hydrologist Steve Buan, at the North Central River Forecast Office, “River levels over the Upper Mississippi River are not ‘yet’ extraordinarily low.”

Buan commented that heavy rain in recent weeks from around Minneapolis to southwest of Duluth was keeping the river levels from reaching extremely low levels to this point, but that could change if days of steady rain do not come soon or thunderstorms make daily visits to the upper part of the basin.

As of July 13, the river level at St. Louis is 5.3 feet and falling and is projected by NWS Hydrologists to dip to under 2.0 feet around July 20.

According to St. Louis Army Corps of Engineers Public Affairs Chief Mike Peterson, “At the low water reference point of minus 3.5 feet, a safety zone is established in the navigation channel and some restrictions by the United States Coast Guard may be put in place.”

The river bottom of the Mississippi is dynamic, always changing so that barge companies and pilots will police themselves until mandatory restrictions are in place.

“Officials will continue to patrol the river and may undertake dredging operations as necessary,” Peterson said.

The Mississippi River drains more than 40 percent of the United States and has the Arkansas, Illinois, Missouri and Ohio rivers as some of its major tributaries, all of which are experiencing abnormally low levels.

Compare the Mississippi River basin to the amount of real estate experiencing abnormally dry and drought conditions this summer.

River levels along the Mississippi as of July 13, 2012 include: 12.2 feet at Thebes, Ill.; 5.3 ft. at St. Louis, Mo.; 5.2 ft. at Vicksburg, Miss. and -4.8 ft. at Memphis, Tenn.

As a point of reference, on July 13, 1988, the river level at St. Louis was -1.0 ft.

Simply put, a negative river gauge reading can occur as the river bottom condition changes from natural causes or dredging.

“Cows are happy in parts of Northern California and not in Florida” is a good way to sum up the findings of new research from the University of Washington, said Yoram Bauman, best known as the “stand-up economist.” Bauman and colleagues found that the decline in milk production due to climate change will vary across the U.S., since there are significant differences in humidity and how much the temperature swings between night and day across the country.

For instance, the humidity and hot nights make the Southeast the most unfriendly place in the country for dairy cows.

Their study combined high-resolution climate data and county-level dairy industry data with a method for figuring out how weather affects milk production. The result is a more detailed report than previous studies and includes a county-by-county assessment – that will be available to farmers – of the impact climate change will have on Holstein milk production in the U.S. through 2080.

Bauman, who contributed to the research while teaching for the UW’s Program on the Environment and is now a fellow at the Sightline Institute, will present the findings during this week’s Conference on Climate Change, held on the UW campus.

Scientists and the dairy industry have long known about and studied the impact of heat stress on cows’ milk production.

“Using U.S. Department of Agriculture statistics, if you look at milk production in the Southeast versus the Northwest, it’s very different,” said Guillaume Mauger, a postdoctoral researcher in the UW’s Climate Impacts Group and co-author of the paper. “It’s reasonable to assume that some of that is due to the inhospitable environment for cows in the Southeast.”

Previous research into how climate affects cow milk production in the U.S. was either limited in geographic scope or was too simplistic, ignoring the impact of humidity, for instance.

But by using detailed climate data covering night and day across the entire country, the researchers made some interesting discoveries. For instance, in Tillamook, Ore., where the climate is humid and the nighttime temperature doesn’t change much, milk production begins to drop at a much lower temperature than in the dry Arizona climate.

Tillamook cows become less productive starting at around 15 C, or 59 F, while those in Maricopa, Ariz., start making less milk at around 25 C, or 77 F. In humid Okeechobee, Fla., cows become less productive at about the same temperature but losses increase at a much faster rate than in Arizona.

Fortunately for cows in Tillamook, however, the temperature there doesn’t stray upward often and so actual milk losses are negligible, the researchers said. In Maricopa, the mean daily losses in summer, when the temperature soars, reach nearly 50 percent.

The authors also found that dairy farmers are already clustering in the most comfortable areas for cows, such as the cool coastal counties of Washington state.

But the outlook isn’t good for areas across the southern U.S. where cows are already less productive in the heat of the summer.

“Perhaps most significantly, those regions that are currently experiencing the greatest losses are also the most susceptible: they are projected to be impacted the most by climate change,” the researchers wrote in the paper.

Still, there’s a notable silver lining in the report. While the researchers project that dairy production averaged across the U.S. will be about 6 percent lower in the 2080s than at the start of the century, other factors are likely to actually boost milk production even more.

“Management practices and breeding are on track to double milk production in Holsteins in the next 30 or 50 years,” Mauger said. “So while a 6 percent drop is not negligible, it’s small compared to other positive influences.”

The research could be valuable to farmers looking to evaluate the cost and effectiveness of methods for keeping cows cool. “You can pick up dairy cows and truck them elsewhere,” said Bauman, who noted that ranchers looking to expand could make decisions based on climate.

The researchers plan to make the data freely available so that farmers can look up their counties and find how the climate may affect their cows.

The researchers hope next to look at the impact climate has on other barnyard animals, such as pigs, and other effects, such as mortality rate, that rising temperature might have on cows.

Other co-authors are Eric Salathe, an assistant professor at UW Bothell and member of the UW’s Climate Impacts Group, and Tamilee Nennich of Purdue University.

Earth Hit by Powerful Solar Flare

France said this week it is mobilizing emergency efforts to stop locust swarms in Africa’s Sahel from spreading farther into drought-stricken Niger and Mali.

The French Foreign Ministry said Tuesday it had released $1 million in emergency funding targeted to Niger — the country currently most affected — through a contribution to National Center for Locust Control in Mauritania.

Part of the funding will also go to help in a regional response to the locust swarms though an emergency fund set up by the U.N. Food and Agriculture Organization.

The latter effort will be aimed at surveying and controlling locust in Mali, where militant Islamists and Tuareg rebels have used the chaos created by the March overthrow of President Amadou Toumani Toure to seize control of the northern part of the country.

“Groups of desert locusts have been identified in recent weeks in the northern part of the Sahelian strip by the surveillance system set up by the countries of the region,” the French ministry said in a statement. “These groups were notably found in northern Niger and Mali where insecurity could hamper the necessary survey and control operations.”

The spread of this locust invasion to the southern part of the Sahel region, Paris said, “would have disastrous consequences, resulting in the loss of crops and the prospect of a worsening food crisis.”

The ministry said the swift mobilization of donors, notably France and the EU, “has already made it possible to cover, within a few days, the immediate needs, estimated by the FAO to be $2.5 million.”

“France will remain particularly attentive to developments in the situation in the weeks and months ahead.”

The Commission for Controlling the Desert Locust in the Western Region, an inter-regional FAO committee working with 11 countries in North Africa and the Sahel, has indicated it plans to double its efforts to stop the plague, France24 reported.

Swarms were first spotted in northern Niger in May, but efforts to keep them from reproducing were hampered by the fact that heavy rainfall earlier in the year had created ideal breeding conditions.

Despite the control efforts, swarms of the insects are moving south into Niger’s agricultural breadbasket, where around 1.2 million acres of crops are at risk of being destroyed.

The unrest in northern Mali has meant FAO efforts to control the locust swarms from spreading there have been brought to a halt.

Swarms of immature locusts have invaded the Kidal and Aguelhok regions in northern Mali, sparking concerns the insects may devastate the country as it reels from drought, conflict, and the displacement of more than 360,000 refugees from the fighting, the United Nations has warned.

“It is difficult to know exactly how the situation is, as it is not safe to send scientific teams there,” Manda Sadio Keita, an FAO program officer, told the U.N. news service IRIN. “We cannot assess and fight locusts anymore.”

The government of Mali estimated in April almost 3 million people were living in conditions of food insecurity in drought-affected areas, while the FAO has since pegged the number at 1.6 million people throughout the regions of Gao, Kidal, Timbuktu and parts of Mopti, Voice of America reported.

Must-See Pics, Time Lapse of “Manhattanhenge”

The cause of rapid sea level rise in the past has been found by scientists at the University of Bristol using climate and ice sheet models. The process, named ‘saddle-collapse’, was found to be the cause of two rapid sea level rise events: the Meltwater pulse 1a (MWP1a) around 14,600 years ago and the ’8,200 year’ event. The research was published in Nature this week.

Using a climate model, Dr Lauren Gregoire of Bristol’s School of Geographical Sciences and colleagues unearthed the series of events that led to saddle-collapse in which domes of ice over North America became separated, leading to rapid melting and the opening of an ice free corridor.

Evidence of these events has been recorded in ocean cores and fossil coral reefs; however, to date the reason behind the events was unclear and widely debated.

Ice domes up to 3 km thick (three times the height of Snowdon), formed in regions of high snowfall and higher topography, such as the Rocky Mountains. Together with the saddles – lower valleys of ice between the domes – these made up the ice sheet.

Towards the end of the last ice age, at the time of mammoths and primitive humans, the climate naturally warmed. This started to melt ice at increasingly high elevations, eventually reaching and melting the saddle area between the ice domes.

This triggered a vicious circle in which the melting saddle would lower, reach warmer altitudes and melt even more rapidly until the saddle had completely melted. In just 500 years, the saddles disappeared and only the ice domes remained.

The melted ice flowed into the oceans leading to rapid sea level rises of 9 m in 500 years during the Meltwater pulse 1a event 14,600 years ago and 2.5 m in the second event, 8,200 years ago.

Dr Gregoire, lead author of the study, said: “We didn’t expect our model to produce such a rapid sea level rise. We got really excited when we realised that the events we simulated corresponded to real events!”

In the model, Dr Gregoire found that saddle-collapse could explain a significant amount of the sea level rise observed: “The meltwater pulse produced by the saddle-collapse can explain more than half of the sea level jump observed around 14,600 years ago. The rest probably came from the progressive melting of ice sheets in Europe and Antarctica.”

This research not only identifies the process which caused the melting of the North American ice sheet and the trigger for rapid sea level rises in the past, but also increases our understanding of the nature of ice sheets and climate change, allowing further questions to be posed and, with more research, answered.

Research like this allows climate and ice sheet models to be tested against evidence from the real world.

If climate models are able to reflect patterns observed in natural records our confidence in them increases. This is particularly relevant where the models are also used to investigate the effect of climate change on ice sheets in the future.

The study was funded by the NICE Marie Curie Research Training Network and the Natural Environment Research Council (NERC), and the numerical model simulations were carried out using the facilities of the Advanced Computing Research Centre (ACRC) at the University of Bristol.