Rising temperatures deplete Colorado River


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The Colorado River provides drinking water for 40 million people. (Katie Rompala/flickr)
Jenna Ladd | February 24, 2017

The volume of the Colorado River has decreased by 19 percent since 2000, and recent research shows that climate change is partly to blame.

Two researchers from Colorado State University and University of Arizona compared temperature, precipitation and water volume in the Colorado River basin from 2000-2014 to historical records dating back to 1896. Since 2000, precipitation in region has decreased by 4.6 percent while temperatures have risen 1.6 degrees Fahrenheit above historical averages. Utilizing existing climate models, the scientists found that the river’s flow should have only decreased by roughly 11.6 percent since the drought began in the area in 2000. Instead, the river’s flow decreased by 19.3 percent due to the effects of global warming, they said.

Published last week in the journal Water Resources, the study read,

“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. Record-setting temperatures are an important and under-appreciated component of the flow reductions now being observed.”

The Colorado River provides drinking water for 40 million people and irrigates 6,300 square miles of agricultural land. Moving forward, the study’s authors said precipitation in the river’s basin would have to increase by 14 percent by the end of the century in order to mitigate the rising temperature’s effects.

Brad Udall of Colorado State University is one of the study’s co-authors. He said, “We can’t say with any certainty that precipitation is going to increase and come to our rescue.”

Warming ponds could speed up climate change


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Small ponds used by researchers at the University of Exeter and Queen Mary University. (University of Exeter)
Jenna Ladd | February 23, 2017

A recent study shows that when freshwater ponds warm, they release more methane and are able to store less carbon dioxide.

Researchers at the University of Exeter and Queen Mary University of London warmed a collection of man-made ponds by four to five degrees Celsius over the course of seven years. The first of its kind, the study found that the amount of methane released by the ponds increased by double while the amount of carbon dioxide the ponds could store decreased by half.

Professor Gabriel Yvon-Durocher was the study’s lead investigator. He said, “Given the substantial contribution small ponds make to the emission of greenhouse gases, it is vital to understand how they might respond to global warming.”

While ponds and lakes only account for about 0.008 percent of the total volume of water on Earth, they are major contributors of carbon dioxide and methane. Greenhouse gases from freshwater sources are mostly the byproduct of organic matter breaking down in low-oxygen environments.

Yvon-Durocher continued, “Our findings show that warming can fundamentally alter the carbon balance of small ponds over a number of years, reducing their capacity to absorb and increasing emissions of methane. This could ultimately accelerate climate change.”

The scientist noted that these findings are different than those normally observed on land, where the effect of rising temperatures lessen over time. In contrast, when ponds warm and release methane, a gas that is known to be 25 times more potent than carbon dioxide, they actually exacerbate warming.

Ponds of less than one meter, such as those used in the study, are responsible for the release of 40 percent of all inland methane emissions.

 

The professor noted, “This accelerating effect in ponds, which could have serious impacts on climate change, is not currently accounted for in Intergovernmental Panel on Climate Change models.”

The complete study can be found in the journal Nature Climate Change.

Extreme Rain from Thunderstorms is Rising Due to Climate Change


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Precipitation change in the U.S. from 1991 to 2012. (NASA)
Jake Slobe | Febraury 20, 2017

This week’s On The Radio segment discusses a recent study linking climate change and an increase in heavy rain events.

Transcript: An increase in extreme rain events could change the ways cities handle storm water management and flooding.

This is the Iowa Environmental Focus.

Rain is increasingly falling in the form of short, localized bursts associated with thunderstorms found a new study released in Science Advances late last month.

The study directly links this increase in heavy rain storms to the warming and moistening of the atmosphere caused by rising greenhouse levels.

The results fit with rainfall trends already observed in the U.S., as well as model predictions that massive rains associated with thunderstorms could become both more common and more intense in the U.S. as the world continues to heat up.

Extreme downpours have already been increasing in the U.S., most notably in the Northeast, where they have increased by 71 percent since mid-century, according to the 2014 National Climate Assessment.

Upon previous research which has also predicted an increase in extreme rain events due to climate change.

To learn more about this study, visit iowaenvironmentalfocus.org.

From the UI Center for Global and Regional Environmental Research, I’m Betsy Stone.

EnvIowa Podcast: Dr. Gregory Carmichael


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Dr. Gregory Carmichael has worked closely with scientists in East Asia since 1983 to address pressing air quality problems in that region. (Tim Schoon/University of Iowa)
Jenna Ladd | February 17, 2017

In Episode 5 of EnvIowa we speak with Dr. Gregory Carmichael, Karl Kammermeyer Professor of Chemical and Biochemical Engineering and Co-Director of the UI Center for Global and Regional Environmental Research, about his extensive research on global air pollution.

Dr. Carmichael shares his experiences collaborating with scientists in China, explains why air quality issues in East Asia should matter to Iowans and offers some perspective about what climate science research may look under the new federal administration.

More than 700 threatened animal species hit hard by climate change


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Tropical marsupials, such as the bushtail opossum, are most likely to be negatively impacted by climate change. 
Jenna Ladd | February 16, 2017

The changing climate has had a significant negative impact on 700 mammal and bird species according to a recent study published in Nature Climate Change.

While the majority of existing research focuses on the impact climate change will likely have on animal species in the future, new research suggests that the future is now. Researchers performed a systematic review of published literature and found that 47 percent of land mammals and 23 percent of bird species on the International Union for the Conservation of Nature (IUCN) list of threatened species have already been been negatively effected by climate change.

At present, the IUCN reports that only seven percent of mammals and four percent of bird species are threatened by the warming planet.

The study found that climate change is impacting animals on every continent. In general, animals that breed more slowly and live in high altitudes are suffering the greatest losses. Mammals with a more specialized diet are most profoundly effected due to regional vegetation change. For birds, species with small dispersal distances and longer generation lengths are most at risk.

The article read, “Our results suggest that populations of large numbers of threatened species are likely to be already affected by climate change, and that conservation managers, planners and policy makers must take this into account in efforts to safeguard the future of biodiversity.”

Those animals belonging to taxonomic orders which have been most extensively studied showed the most significant trend. Michela Pacifici of the Global Mammal Assessment program at Sapienza University of Rome is the report’s lead author. He said,

“We have seriously underestimated the effects of climate change on the most well-known groups, which means those other groups, reptiles, amphibians, fish, plants, the story is going to be much, much worse in terms of what we think the threat is from climate change already.”

Animals that live in tropical regions, like primates and marsupials, are at the highest risk because they have adapted to that biome’s climate, which has been relatively stable for thousands of years. The study said, “Many of these [animals] have evolved to live within restricted environmental tolerances and are likely to be most affected by rapid changes and extreme events.”

Just two orders of mammals, rodents and insect-eaters, were found to have benefited from climate change. Generally, these animals thrive in a variety of climates, breed quickly, and can burrow to protect themselves from changes in weather.

One of the study’s authors, James Watson, a researcher at the University of Queensland in Australia, said climate researchers should shift their focus to present-day.

“It’s a scientific problem in that we are not thinking about climate change as a present-day problem, we’re always forecasting into the future,” Watson added, “When you look at the evidence, there is a massive amount of impact right now.”

Iowa State researchers receive grants to improve glacier flow models and sea level predictions


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                         Calving of the Aialik Glacier in Kenai Fjords National Park in Alaska. (Alaska National Park Service)
Jake Slobe | February 15, 2017

Iowa State University’s Neal Iverson and a team of researchers are working on research that will predict how much glaciers will contribute to the rise of sea levels.

The research will focus on the extent to which glacier-flow to oceans is likely speed up over the next century as the climate warms.

Iverson, an Iowa State University professor of geological and atmospheric sciences who has studied glaciers in Iceland and Norway, and the rest of the research team will look to lab experiments and field work to build more realistic computer models of glacier flow.

Iverson said about the project:

“Glaciologists are trying to predict how fast glaciers will flow to the oceans. To do that, we need new lab and field data to include complexity in models that is usually neglected. These are complicated systems. Modeling them is hard. But we need to include how water in ice affects its flow resistance, and we need sliding laws that are based on the real topography of glacier beds and that include rock friction. Adding these things really matters.”

Two new grants will help Iverson and his team fund their research, both of which grants are from the National Science Foundation.  The research will also receive funding from the United Kingdom’s Natural Environment Research Council to support the work of applied mathematicians at the University of Oxford in England.

Iverson is the lead investigator on both grant proposals. The other researchers are Lucas Zoet, an assistant professor at the University of Wisconsin-Madison and a former postdoctoral research associate at Iowa State; Ian Hewitt, an associate professor and university lecturer at Oxford’s Mathematical Institute; and Richard Katz, a professor of geodynamics at Oxford.

The first project will look at temperate ice, or ice at its melting point, and how this soft, watery ice resists deformation. That’s important because the resistance to deformation of temperate ice at the edges of ice streams – areas of rapid ice flow within the Antarctic ice sheet that can be hundreds of miles long and tens of miles wide – holds back the flowing ice.

The second project will support development of better “sliding laws” to help predict the sliding speeds of glaciers and ice sheets. Sliding laws are the mathematical relationships between the glacier sliding speed and the factors that control it, such as the stresses below the glacier, the water pressure there, the topography of the glacier bed and the concentration of debris in glacier ice.

Both projects will use the glacier sliding simulator Iverson has been using since 2009 to study glacier movement.

The new projects will add complexity to Iverson’s lab experiments. Debris, for example, will be added to the ice ring to study friction between it and the rock bed during sliding. In other experiments, temperate ice will be sheared between rotating plates to study how its resistance to flow depends on its water content.

University of Iowa drinking water exceeds maximum contaminant levels for disinfectant by-products


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Chlorine treatments react with organic matter in waterways to form Total Thihalomethanes, which have been linked to cancer and reproductive problems. (Jenna Ladd/CGRER)
Jenna Ladd | February 14, 2017

University of Iowa facilities management received notice on February 1 that its drinking water system contains levels of Total Trihalomethanes (TTHM) that exceed the federal drinking water standard.

In an email sent out to University faculty, staff and students on February 9, it was reported that the drinking water tested on average between 0.081 and 0.110 mg/L over the last year. The U.S. Environmental Protection Agency’s maximum contaminant level (MCL) for TTHM is 0.08 mg/L.

TTHM is a group of four chemicals: chloroform, bromodichloromethane, dibromochloromethane and bromoform. TTHM form when chlorine reacts with natural organic matter like leaves, algae and river weeds in drinking water. In its statement, the University said that more chlorination was necessary this year because higher than usual temperatures led to more organic waste in waterways.

The notice read, “You do not need to use an alternative (e.g., bottled) water supply. Disease prevention specialists with University of Iowa Hospitals and Clinics say special precautions are not necessary.”

Chloroform and dibromochloromethane are Class B carcinogens, meaning they have been shown to cause cancer in laboratory animals. TTHM has also been linked to heart, lung, kidney, liver, and central nervous system damage, according to a report by the University of West Virginia.

University officials cautioned, “However, some people who drink water-containing trihalomethanes in excess of the MCL over many years may experience problems with their liver, kidneys, or central nervous system, and may have an increased risk of getting cancer.”

A study by the California Department of Health suggests that even short-term exposure to high TTHM levels in drinking water can have serious consequences for pregnant women. Scientists monitored 5,144 women during their first trimester of pregnancy. Participants who drank five or more glasses of cold home tap water containing 0.075 mg/L or more of TTHM had a miscarriage rate of 15.9 percent. Women that drank less than five glasses per day or who had home tap water with less than 0.075 mg/L TTHM had a miscarriage rate of 9.5 percent.

A reverse osmosis filtration system for the University of Iowa drinking water supply is currently in its design phase. Facilities management expects to have the new system up and running within the next 18 months. Officials say it will help address Iowa’s nitrate problem and filter out naturally occurring organic matter, resulting in fewer TTHM.