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

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.

Interactive tool to predict future days above 100 degrees


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With a new web-based platform, users can see hot day projections for many U.S. cities and towns. (Climate Central)
Jenna Ladd| August 18, 2017

By now it’s common knowledge that as greenhouse gases continue to accumulate in our atmosphere, intensely high temperatures are likely to occur more frequently.

But Climate Central, a climate research and news organization, has developed a way for residents of the continental U.S. to see exactly how much their communities will be affected. The interactive tool allows users to type in the name of their city or town and view the average number of days that will exceed specific temperature thresholds in 2050, 2075 and 2100.

The analysis includes data for nearly 30,000 cities and towns of various sizes from across the continental U.S. Each graph provides two possible outcomes: one in which greenhouse gas emissions continue as usual and one in which they are moderately curtailed.

Researchers based their projections on aggregated data from 21 global climate models.

At present, Des Moines experiences an average of zero days per year when the actual temperature is above 100 degrees Fahrenheit. According to this study, the city will likely see 15 days annually that exceed the temperature threshold in 2050 and up to 30 per year in 2100.

This year is on track to be the hottest year ever, followed by 2016, 2015, and 2014, respectively.

New study assesses flood risks for schools nationwide


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The impact of flooding on schools is often compounded by aging infrastructure, according to a recent study. (FEMA)
Jenna Ladd| August 8, 2017

A recent study by the Pew Charitable Trusts generated flood risk scores for 84,123 primary and secondary schools nationwide.

The report’s authors pointed out that flooding is the most costly and common natural disaster, affecting every region of the U.S. Many times, severe floods badly damage schools, causing them to close. For example, the study points out, floods in West Virginia in June 2016 cost $130 million in damage to regional schools.

Researchers used three metrics to generate county-wide composite flood risk vulnerability scores for schools in all fifty states including: a school’s location within a designated flood zone, the percentage of a school’s neighborhood (as represented by ZIP code) located within a flood zone, and the number of historical flood-related federal disaster declarations in that county.

Among the study’s major findings are that flood risk is distributed across diverse regions of the country. Schools with the highest flood risk scores were located in the Atlantic Coast, Gulf Coast, Mississippi River corridor, and southwestern Arizona. Similarly, those schools with the highest composite flood risk scores were located in both coastal and inland regions. Those 100 counties with the highest composite flood risk scores include 6,444 schools that serve almost 4 million students.

The study made some recommendations for steps policymakers can take to increase flood resiliency for schools. They included generating up-to-date local flood maps, developing pre-disaster flood plans for schools, working to leverage federal assistance, and relocating schools out of floodplains if possible.

The Pew Charitable Trusts full analysis can be found here.

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The highest flood risk areas are scattered across many regions of the country. (Pew Charitable Trusts)

Wildfires become more common and intense as Earth warms up


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Smoke billows from the Lodgepole Complex wildfire of eastern Montana. (Montana Public Radio)
Jenna Ladd| July 26, 2017

A wildfire as large as New York City is currently ripping across eastern Montana, and experts say climate change making fires like these larger and more common.

As climate change takes hold, wet areas are becoming wetter and dry areas are becoming drier. Rising temperatures in spring and summer months mean that soils are remaining dry for longer, which makes drought more likely, thereby lengthening the wildfire season.

According to the Union of Concerned Scientists, wildfires have become more likely and more intense since the 1980’s. They last nearly five times as long, occur almost four times as often and burn more than six times the land area on average.

Moving forward, residents of fire-prone regions can expect the wildfire season to lengthen. In the southwestern U.S., scientists predict wildfire season will increase from  seven months to twelve months.

The economic impacts of wildfires are staggering. Since 2000, the U.S. Forest Service has spent more than $1 billion on fire suppression in one fiscal year on two occasions. During the first decade of the 21st century, wildfires cost an average of $665 million per year in economic damages.

In their full report on this issue, the Union of Concerned Scientists say it’s not too late for humans to slow the course of climate change. They write,

“The global temperature is increasing and the climate is changing due to the greenhouse-gas emissions we have already produced, leading to a likely rise in the incidence of wildfires. But it is not too late. What we do now has the power to influence the frequency and severity of these fires and their effects on us.”

On The Radio – Urban areas to suffer economic costs of climate change


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According to a recent study, the world’s larger cities, such as New York City, will be hit hardest by global warming. (Chris Goldberg/flickr)
Jenna Ladd| July 24, 2017

This week’s On The Radio segment describes how climate change will have a disproportionate economic impact on urban areas.

Transcript: A recent study by an international group of economists found that climate change will likely cost cities twice as much as rural areas.

This is the Iowa Environmental Focus.

The study, published in the journal Nature Climate Change, found that the largest quarter of the world’s cities could see more intense temperature spikes by 2050 due to the combined effect of global warming and urban heat island effects. Urban heat islands are formed when naturally cooling surfaces like vegetation and bodies of water are replaced by surfaces that trap heat like concrete and asphalt.

Higher temperatures in cities have negative economic impacts including less productive workers, higher cooling costs for buildings and poorer water and air quality. On average, the global gross domestic product (GDP) is expected to drop by 5.6 percent by 2100 due to climate change. The combined climate change and heat island effect means that the most-impacted cities are expected to lose about 11 percent of their GDP in the same period.

The economists noted that some actions can be taken to mitigate these effects including installing cooling pavements and green roofs and reintroducing vegetation in urban areas.

To read the full story and for more information, visit iowa-environmental-focus-dot-org.

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