On The Radio – Humidity on the rise in Iowa


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Increased humidity poses health risks for Iowans according to the 2017 Iowa Climate Statement. (Teresa Shishim/flickr)
Jenna Ladd| September 18, 2017

This week’s On The Radio segment discusses how humidity has increased significantly during all seasons in all parts of Iowa since 1971.

Transcript: Humidity in the state of Iowa has increased significantly since 1971, according to the 2017 Iowa Climate Statement released last month.

This is the Iowa Environmental Focus.

Absolute humidity, usually measured by dew point temperature, has increased significantly in all parts of Iowa during all seasons. The largest increase was found in Dubuque with a 23 percent increase in springtime humidity from 1971 to 2017.

The statement’s lead co-authors Gene Takle, director of Iowa State’s Climate Science Program and professor of geological & atmospheric sciences at ISU, and Betsy Stone, associate professor of chemical and biochemical engineering at the University of Iowa, warned that increasing humidity makes conditions more favorable for increased rainfall, extreme rain events, mold and mosquitoes.

High humidity also presents health concerns for Iowans. More humid air along with rising temperatures can make conditions dangerous for manual laborers and individuals sensitive to heat exhaustion and heat stroke.

Titled, It’s Not Just the Heat, It’s the Humidity!, the statement ends with a call for Iowans to do more to mitigate the effects of climate change through improving energy efficiency, cutting emissions and advancing renewable energies.

For more information, visit Iowa-environmental-focus-dot-org.

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

On The Radio – Storms like Harvey more likely due to changing climate


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Texas National Guard members rescue residents in a heavily flooded area of Houston. (Texas Military Department/flickr)
Jenna Ladd| September 11, 2017

This week’s On The Radio segment discusses how climate change is making storms like Harvey more likely.

Transcript: Over 51 inches of rain fell in the Houston area last month during Hurricane Harvey, setting a record for the continental U.S., and scientists say a changing climate added to the deluge.

This is the Iowa Environmental Focus.

The Clausius-Clapeyron equation, a law of thermodynamics, says that the warmer a body of air is, the more moisture it can hold. Sea surface temperatures near where Harvey picked up its strength were about 1 degree Celsius higher than average, making the air above it warmer too. In this case, the atmosphere surrounding Hurricane Harvey was able to hold roughly three to five percent more moisture than usual.

In addition, sea levels have risen by about six inches in the last few decades due to global warming. Even minimal sea level rise can lead to a large increase in damages to structures on land during a flood.

While climate change did not cause Hurricane Harvey directly, scientists say it will likely make category four storms like it more frequent in the future.

For more information, visit iowa-environmental-focus-dot-org.

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

Lessons for Iowans in the wake of Harvey


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A map from the National Hurricane Center illustrates predicted landfall for Hurricane Irma, a category 5 storm, over the weekend. (National Hurricane Center)
Jenna Ladd| September 7, 2017

As some of the floodwater finally recedes from the Houston area following Hurricane Harvey,  Hurricane Irma, a category five storm, threatens to devastate the Florida Keys this weekend.

Climate change increased the amount of rainfall that fell on Houston during the recent storm, according to a statement from Clare Nullis Kapp, media officer for the World Meteorological Organization. Karen Tigges, a Des Moines resident and operations analyst at Wells Fargo, said in a recent Des Moines Register Letter to the Editor that Harvey has something to teach the people of Iowa. The letter reads:

“Houston: A tragic example of a city caught at the mercy of worsening storms and increased rainfall. Flooding is nothing new to Houston, but it appears that this time they are really paying the price for unwise growth.

Unfortunately, flooding is not unfamiliar to the city of Des Moines either. We are growing in the metro as well. We must take the warnings of storm events seriously. It’s said that the lack of zoning ordinances in Houston led to the loss of wetlands and grasslands that could have absorbed at least some of the onslaught of water. How does that compare with planning for growth here in the metro area? Is the growth of our urban areas leading to higher risks of flooding due to more impermeable surfaces in the form of more paved roads and rooftops?

As the city prepares for a future that will likely include more intense rainfall events, thanks to a warmer, more humid climate, we citizens need to take an active role in seeing that effective planning and policies are put in place to make Des Moines ready to face this unpleasant reality.

We can do that by weighing in on the city’s new planning and zoning code. We also need to do that by electing and supporting leaders that will be proactive in setting the course of the metro area on a path of resilience and preparedness for what storms of the future may bring.”

— Karen Tigges, Des Moines

Houston flood expected to drain slowly


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Give its flat landscape and dearth of flood control infrastructure, the city of Houston will rely primarily on slow-moving bayous to drain the area. (Adam Baker/flickr)
Jenna Ladd| September 1, 2017

While the downpour in Houston has finally subsided, the Texas city has few options for draining the 15 trillion gallons of water that fell in the region.

The city of Houston has no levees or pumps or flood walls it can call on to drain water more quickly back into surrounding bayous. As a low-lying coastal plain, it also has a rather flat landscape. Arturo Leon, a professor of water resources engineering at the University of Houston said, “This means the capacity for drainage is very slow. If there were a slope, then it would drain faster,” in a report by Scientific American.

In the last thirty years, the city has grown a great deal, all without any zoning laws that regulate development, even in flood prone areas. For example, since 2010 about 7,000 residential buildings have been built on land the federal government considers a 100 year floodplain, according to a review by the Washington Post. Stormwater drainage systems have not kept pace with the area’s development.

Sam Brody, director of the Center for Texas Beaches and Shores at Texas A&M University, said, “Houston is the Wild West of development, so any mention of regulation creates a hostile reaction from people who see that as an infringement on property rights and a deterrent to economic growth. The stormwater system has never been designed for anything much stronger than a heavy afternoon thunderstorm.”

As a result, the city relies heavily on surround bayous to reabsorb rainwater. Bayous are slow moving, and especially so on Houston’s flat landscape.

A list of options for donating to victims and displaced residents in the area can be found here.

Climate change to make storms like Harvey more frequent, intense


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A Texas National Guard member rescues a Houston resident during Hurricane Harvey. (The National Guard/flickr)
Jenna Ladd| August 30, 2017

More than fourteen million olympic-sized swimming pools could be filled with the amount of rain that has fallen in Houston as a result of Hurricane Harvey, and scientists say that climate change added to the deluge.

To begin, sea surface temperatures near where Harvey picked up its strength were about 1 degree Celsius higher than average. The Clausius-Clapeyron equation, a law of thermodynamics, says that the warmer a body of air is, the more moisture it can hold. In this case, the atmosphere surrounding Hurricane Harvey was able to hold roughly three to five percent more moisture than usual.

“The water in the Gulf of Mexico is the heat reservoir to support these hurricanes,” said Ben Kirtman, an atmospheric scientist at the University of Miami, in a report from NPR. Kirtman added, “For a small change in temperature, you get a huge amount of evaporation.”

In the last three decades, sea levels have risen worldwide by about six inches thanks to a warming climate and, in part, to human activities like offshore oil drilling. Higher sea levels make inland floods more devastating.

Climate Central scientist Ben Strauss said, “Every storm surge today reaches higher because it starts from a higher level, because sea level is higher. A small amount of sea-level rise can lead to an unexpectedly large increase in damages to most kinds of structures.”

Scientists are careful to point out that climate change did not directly cause Harvey, but is likely to produce storms like it more often. A recent report from the National Academy of Sciences, Engineering and Medicine revealed that category 4 hurricanes like Harvey will occur more frequently in the future due to a warming climate.

So far, fourteen casualties have been identified as the storm continues to devastate the area.

Climate change to significantly alter urban climates


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Climate Central and the World Meteorological Organization’s list of top ten fastest warming cities. (Climate Central)
Jenna Ladd| August 28, 2017

Climate Central in partnership with the World Meteorological Organization have created an interactive tool detailing how average summer temperatures in cities around the globe are likely to change by 2100.

The effects of global warming are often compounded in cities by the urban heat island effect, which can make cities up to 14°F hotter than rural areas. On average, land temperatures are expected rise by 8.6°F by 2100, but some cities will warm much more. For example, the analysis found that if emissions are not curbed, Ottawa, Canada is projected to have a climate comparable to Belize City by 2100. In the same scenario, residents of Chicago can expect to have a climate more similar to Juarez, Mexico.

At present, more than 54 percent of the world’s population call cities home. Given that rising global temperatures will felt more acutely in urban areas, it is no surprise that many U.S. mayors have pledged their continued support of the Paris Climate Accord, despite President Trump’s decision to withdraw.

Check out the interactive tool here to see how climate change is projected to change the climate in your city.

August rainfall benefits some parts of Iowa


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August rainfall saved much of Iowa from severe drought conditions, but parts of south central are still experiencing extreme dryness. (Iowa DNR)
Jenna Ladd| August 25, 2017

Rainfall in the last part of August helped to lift many parts of Iowa out of drought conditions, but some parts of the state are still experiencing extreme drought, according to the latest Water Summary Update.

The Water Summary Update is a succinct monthly report of Iowa’s water resources and those events that affect them prepared by the technical staff at Iowa DNR, the Iowa Department of Agriculture and Land Stewardship, IIHR—Hydroscience and Engineering, and the U.S. Geological Survey, in partnership with Iowa Homeland Security and Emergency Management Department.

The latest summary revealed that while August started off very dry, high rain totals increased groundwater levels and streamflow in many parts of the state. The total area of the state classified as experiencing drought or dryness decreased from over 70 percent at the beginning of the month to 55 percent this week. In contrast, south central Iowa is still experiencing D2 and D3 drought conditions. Clarke county and Wapello county are seeing the most extreme dryness.

Researchers point out that August temperatures this year have been about three to four degrees cooler than normal, on average. Lower temperatures slow down evaporation rates and provide a protective factor for crops in drought-stricken areas.

To follow Iowa DNR’s regular water summary update, visit their website here.