Climate change and wild spring weather


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The Greenland block is a high pressure atmospheric block that hangs above Greenland and affects weather moving down to lower latitudes. (flickr/Stig Nygaard)

Jenna Ladd | April 18, 2018

By-in-large, spring weather has been arriving earlier each year in the United States. For instance, the frost-free season was 10 days longer between 1991 and 2011 than it was from 1901 to 1960.

This may come as a shock to Midwesterners, who saw several inches of snow fall this Sunday, April 15th. So what’s going on?

Among some other factors, the Greenland Block has a lot to do with the snowy spring of 2018, according to Dr. David Mechem of the University of Kansas. Mechem, a professor of geography and atmospheric science, explained that there is a persistent atmospheric area of high pressure above Greenland which funnels cold air from the poles straight into the mid-latitudes of North America. He told KCUR that the block was in place throughout February and March and is finally starting to break down, which would bring long-awaited warmer temperatures to the midwest.

Further research is needed to establish exactly what kind of effect climate change has on spring weather, but scientists are noticing some changes. Winter storms (even if they happen in April) have increased in frequency and intensity in the Northern hemisphere since 1950 according to the National Climate Assessment. Nor’easter winter storms plague the eastern U.S. and are caused by the the cold air from the Arctic and warm air from the Atlantic interplaying. This year, that region of the U.S. saw several Nor’easters in very quick succession, which is unusual. A recent study in the journal Nature Communications found that as the Arctic’s climate continues to warm at an alarming rate, winter storms becoming more likely in the eastern U.S.

The good news is that as the Greenland block continues to break down, residents of the mid-latitudes can expect spring to finally arrive. The bad news is that unpredictable spring weather can be expected to continue coming years as the climate continues to change.

Earlier spring could threaten bees


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The new study looked at three bee species in the Rocky Mountain region. (CL Baker/flickr)
Jenna Ladd | October 5, 2017

A new study has found that longer spring seasons associated with climate change may be harmful to certain bee populations.

Researchers focused on a region in the Colorado Rocky mountain range and three species of bees. Using 40 years of climate and flower data collected by David Inouye, a professor emeritus at the University of Maryland, College Park, the report concludes that mountain snow in the area is melting earlier than it used to, resulting in longer spring seasons with longer growing seasons for flowers. Somewhat surprisingly, there has been an increase of total number of days with low flower availability since spring began getting longer.

One of the study’s co-authors, Rebecca Irwin of North Carolina State University, said to the Scientific American, “Years that have a lot of days with low floral abundance seem to be years that have really low snowfall and early snowmelt.”

The study points out that when flowers emerge too early, they are susceptible to early spring frosts which can kill some of them off. Additionally, if snow melt begins flowing down mountain sides too early in the spring, there can be drought conditions later in the summer when it runs out.

It was found that years with a lot of low floral abundance days also had lower bee populations. The scientists write, “Our study suggests that climate-driven alterations in floral resource phenology can play a critical role in governing bee population responses to global change.”

For now, flood forecast good news


The Iowa River in Iowa City, Iowa.
The Iowa River in Iowa City, Iowa.

The National Weather Service issued its first flood potential outlook of the year last week.

Below are locations along the Iowa River and the probability that flooding will occur between now and May 26:

  • Iowa City: Minor flooding, less than 5 percent; moderate flooding, less than 5 percent; major flooding, less than 5 percent
  • Lone Tree: Minor flooding, 18 percent; moderate flooding, 12 percent; major flooding, less than 5 percent
  • Marengo: Minor flooding, 58 percent; moderate flooding, 35 percent; major flooding, less than 5 percent

However, experts are closely watching the frost depth of the ground as spring rains near.

For the full story, click here.

On the Radio: Warmest March on record alters Iowa’s environment


Photo by Kenneth Ristau, Flickr.

Listen to this week’s radio segment here or read the transcript below. This week’s episode discusses the effects of an unusually warm March on Iowa’s agricultural community.

Are you curious how the warmest March on record affected Iowa’s farming?

This is the Iowa Environmental Focus.

Continue reading

Mild winter could mean more pests this spring in Iowa


Photo by Frank. Vessen, Flickr

The warm winter could mean an increase in pests this spring in Iowa. Some pests that normally freeze during the winter did not, and therefore bugs are appearing earlier than usual.

Some farmers are worried about the increase in pests. Consequently, some are planning to spray their crops with pesticide earlier this year than they otherwise would.

On the other hand, some entomologist argue that there will be little difference in the number of pests this spring because some insects need snow cover to survive the winter – many of these insects likely did not survive the mild winter.

Read more about this spring’s pest projections from the Des Moines Register here.