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.

Lyme disease more common due to climate change


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Deer ticks thrive in hot and humid forested areas. (flickr/Joslyn Gallant)
Jenna Ladd| August 17, 2017

As temperatures and humidity rise in the United States, conditions are becoming more favorable for disease-carrying deer ticks.

The U.S. Environmental Protection Agency (EPA) reports that climate change has expanded the geographical range of ticks. Deer ticks specifically are most active when temperatures are above 45 degrees Fahrenheit and humidity is at least 85 percent. As temperatures and humidity rise in many parts of North America, so too are tick populations. The EPA reports that the incidence of Lyme disease in the U.S. has doubled since 1991.

The Northeastern U.S. has experienced the sharpest increase Lyme disease transmission. This part of the country is becoming more humid, making conditions better for ticks to emerge from the ground and latch onto hosts. New Hampshire, Maine, and Vermont have seen the largest spike in Lyme disease incidence since 1991, followed closely by Delaware and Massachusetts. On average, the EPA reports, these states now see 50 to 100 more cases per 100,000 people than they did in 1991.

In the future, deer tick populations are expected to double in the U.S. and become up to five times more numerous in Canada.

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Incidence of Lyme disease per 100,000 people. (EPA)

CGRER unveils 2017 Climate Statement focused on humidity


From left to right: Gene Takle, director of the Iowa State University Climate Science Program; Betsy Stone, associate professor in the University of Iowa Department of Chemical and Biological Engineering; and David Courard-Hauri, director of the Environmental Science and Policy Program at Drake University, speak at a press conference for the 2017 Iowa Climate Statement. Takle, Stone, and Courard-Hauri contributed to the statement, which focuses on how increased humidity is a side effect of climate change. (CGRER/Joe Bolkcom)

Katelyn Weisbrod | August 9, 2017

Iowa has experienced a serious increase in humidity since 1971, according to leading climate scientists in the state.

This increase of 8 percent to 23 percent, varying for different cities across the state, can be attributed to climate change.

“Absolute humidity, which is typically measured by dew point temperature, has increased statewide from 1971 to 2017. Measurements show Dubuque had the largest increase in humidity, a springtime increase of 23 percent,” said Gene Takle, director of the Climate Science Program at Iowa State University.

The 2017 Iowa Climate Statement, which was released by the Center for Global and Regional Environmental Research today, describes the impact this high humidity has on people, animals, crops, and infrastructure. The statement was signed by 190 science faculty and researchers from 39 Iowa colleges and universities.

These impacts are far greater than just discomfort. High humidity leads to hazardous health conditions for workers, worsened asthma conditions, higher costs of air conditioning, more waterlogged soil, and stress on crops, livestock, and pets.

The statement calls Iowans to recognize the damaging effects of increased humidity, and to understand more must be done to mitigate the effects of climate change.

Climate change to decrease average number of mild weather days


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Residents enjoy pleasant weather at Noelridge Park in Cedar Rapids, Iowa. (Louis/flickr)
Jenna Ladd | January 24, 2017

The first of its kind, a recent study found that climate change is likely to decrease the number of “nice weather” days worldwide.

The authors of the study, scientists from the National Oceanic and Atmospheric Association and Princeton University, define “nice” or “mild” days as those days when temperatures are between 64 and 86 degrees Fahrenheit, dew points are below 68 degrees Fahrenheit and less than half of an inch of rain falls. Currently there are an average of 74 nice days globally per year, but that number is likely to drop to 70 in the next twenty years and to 64 by 2081.

Karin van der Wiel is a postdoctoral researcher at Princeton University and lead author of the study. She said,

“We used a climate model to simulate the current climate. In that simulation we counted the number of mild days. Then, we increased greenhouse gases in the climate model to simulate the future effects of climate change. This leads to increasing temperatures, changes in humidity, changes in precipitation over the whole world and with very specific patterns. In this new, future climate, we counted the number of mild days again. We could then calculate the change — increase or decrease — of mild weather days for each location globally.”

Not all corners of the Earth will be affected equally, however. Tropical regions are expected to lose the most nice days, with some areas losing up to 50 per year by the end of this century. Meanwhile, London is expected to gain 24 nice days each year.

Predictions for Cedar Rapids, Iowa mirror global averages. Eastern Iowa currently enjoys 76 nice days annually; researchers say that number is expected to drop to an average of 72 between 2016 and 2035 and to 66 each year between 2081 through 2100.

Frequent high humidity makes it tough for Iowa to meet the pleasant weather criteria outlined in the study. Absolute humidity has risen by 13 percent during the summer months in Des Moines since 1970, according to Iowa State climate scientist Gene Takle. Increased humidity also contributes to the extreme rain events that have plagued Iowa in recent years.

van der Wiel said, “Mild weather is something everyone knows, experiences, and has memories of,” she continued, “Our study shows that human-caused climate change is going to lead to changes in mild weather all over… The changes are happening now, and where people live.”

Iowa sees the “humidity effect” this week


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Photo by Pentax_clic; Flickr

This week’s climate in some Iowa cities has been notably warm. However, the warmer than usual climate is not due to abnormally high temperatures, but rather high humidity levels.

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Photo by Iowa State University Department of Agronomy

The chart above shows the difference between temperature and heat index at an 80 or above degree level. Continue reading