Intense summer heat to become more likely due to climate change


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Sydney, Australia saw record heat this summer, with mean temperatures 37 degrees Fahrenheit above average. (Bernard Spragg/Flickr)
Jenna Ladd | March 3, 2017

Southern Australia just endured its hottest summer ever recorded, and recent research found that the likelihood of more extreme summer weather is on the rise.

Following summer months where Sydney’s mean temperature remained 37 degrees Fahrenheit above average, Dr. Perkins-Kirkpatrick at the University of New South Wales in Sydney began to study the relationship between human-induced climate change and summer heat waves.

Along with other researchers at the World Weather Attribution, Perkins-Kirkpatrick concluded that climate change has made it 50 times more likely that New South Wales will experience another similarly scorching summer. Simply put, before 1910 extreme weather like that experienced this summer was likely to occur once every 500 years, now it is likely to occur every 50 years on average. If climate change remains unabated, researchers say that likelihood could increase even more.

The report said, “In the future, a summer as hot as this past summer in New South Wales is likely to happen roughly once every five years.”

Energy companies in New South Wales had trouble supplying enough electricity to meet the demand for air conditioning units during the heatwave’s most intense days from February 9th through the 11th. Meanwhile, according to report by The Guardian, Australian Prime Minister Malcolm Turnbull criticized renewable energy efforts, calling renewable energy goals in the country “completely unrealistic.”

Dr. Andrew King of Melbourne University was another one of the report’s authors. He said, “Yes, people would have experienced 40C [104 degrees Fahrenheit] days several decades ago around different parts of Australia and in Sydney but we know that these incidences of very hot days are getting more frequent and we are setting more records for heat.”

King added, “The purpose of the analysis in this report is to raise awareness that climate change is already impacting on weather in Australia. Hopefully it motivates action on climate change, because we know what the solution to climate change is.”

Winter tornados move through Midwest


West of Tuscaloosa, Alabama
(Frank/flickr)
Jenna Ladd | March 2, 2017

More than 20 tornados ripped through parts of Iowa, Missouri, Illinois, Indiana and Tennessee on Tuesday.

The severe thunderstorms and tornadoes killed at least three people and left thousands of residents in the Midwest and Southeastern U.S. without electricity. While tornados during winter months are rare, they seem to be happening with increasing frequency.

Typically wintertime tornados form when a forceful jet stream moves across the Southern U.S. and meets colder, retreating air fronts. According to The Weather Channel, usually these tornados crop up in the Deep South, however, in February 2016 severe tornados touched down in Pennsylvania and Virginia, ultimately killing seven people.

On average, February is second-least tornadic month of the year, but recently averages for that month are increasing. February 2008 had 146 total tornados, making it the most tornadic February since the 1950s, and February 2016 came close behind with 138 total twisters.

While an abundance of scientific evidence links climate change with the increasing frequency of extreme weather events like heat waves and coastal flooding, the relationship between climate change and tornado frequency remains unclear.

Due to particularly strong jet-stream level energy characteristic of the winter months, winter tornados can occur at any time of the day or night, unlike more predictable spring and summer tornados that almost always form during the late afternoon and evening. The Weather Channel also points out that it is common for winter twisters to be wrapped in rain, making them more difficult to spot.

Experts remind Midwestern and Southeastern U.S. residents that severe weather in the winter months can be deadly and to create or review their severe weather plans.

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(The Weather Channel)

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.”

Wild reindeer shrink in size and number


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A recent study found that the largest herd of wild reindeer in the world’s population is decreasing rapidly due to warming temperatures in northern Russia. (Hermanni Tommonen/flickr)
Jenna Ladd | December 13, 2016

The wild reindeer, a holiday icon, is facing sharp population decline due to climate change.

Andrey Petrov, director of the University of Northern Iowa Arctic Center, led a study of the largest reindeer herd in the world, located on the Taimyr Peninsula in the northernmost tip of Russia. Petrov’s work shows that the herd’s population has dropped from 1 million reindeer in 2000 to about 600,000 today. Scientists say rising temperatures in the region may be the cause.

Petrov said, “Climate change is at least one of the variables.” He added, “We know in the last two decades that we have had an increase in temperatures of about 1.5C overall. And that definitely impacts migration patterns.” During his presentation at the Fall Meeting of the American Geophysical Union (AGU) in San Francisco on Monday, Petrov explained that the longer distance the animals have to travel in order to find cold weather is increasing calf mortality. When the reindeer have to travel further and to higher elevations in the winter, it is also more difficult to find land bearing food in the summer months. Petrov also explained that the region’s rivers are growing wider as ice in the area melts, causing more deaths as the herd attempts to swim across bodies of water.

“Reindeer are tremendously important for biodiversity – they are part of the Arctic food chain and without them other species would be in trouble,” he said. Petrov added, “Thousands and thousands of people rely on wild reindeer; it is the basis of their subsistence economy. So it’s about human sustainability too.”

Wild reindeer are also shrinking in size. Scottish and Norwegian researchers recently released a study which found that the average weight of reindeer on Svalbard, a chain of islands north of Norway, has fallen from 121 lb. in the 1990’s to 106 lb. today. Professor Steve Albon, an ecologist at the James Hutton Institute in Scotland, said, “Warmer summers are great for reindeer but winters are getting increasingly tough.” The researchers explained that less snowfall during warmer winters means that the reindeer have to traverse sheets of ice, making it harder for the animals to reach food sources.

In contrast to the Tamiyr population, the Svalbard herd is growing in size.”So far we have more but smaller reindeer,” Albon said. He added that the growing population means competition for food has become more intense.

Researchers perplexed by tornado clusters’ growing size


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An image of a tornado touching down in Oklahoma in May of 1981 from the National Oceanic and Atmospheric Administration’s photo archive. (NOAA/flickr)
Jenna Ladd | December 2, 2016

A recent study in the journal Science reveals that tornado outbreaks are growing in size, and scientists are unsure why.

The study was published just days after 18 tornadoes devastated parts of the Southeast United States Tuesday night into Wednesday morning. The study’s lead author, Michael Tippett of Columbia University, said that 50 years ago tornado clusters, may have involved about 12 tornados, now they average roughly 20. The researchers studied the most extreme outbreaks, which happen about once every five years, and discovered a steady increase in tornado cluster size since the mid-1960’s.

Before the outbreak on Tuesday, 2016 had seen a record low number of tornadoes. In an interview with the Associated Press, Tippett said,“Something’s up. The tornadoes that do occur are occurring in clusters. It’s not any increase in the (total) number of tornadoes.” In contrast with upticks in other kinds of extreme weather, researchers are not seeing a connection between human-induced climate change and larger tornado clusters. Tippett said, “It’s not what we expected. Either it’s not climate change because not everything is, or it is some aspect of climate change we don’t understand yet.”

The article mentioned that the circulation of warm water in the Pacific and Atlantic oceans could be responsible for the tornado clusters’ growth over the years, but there is no evidence yet to support this claim.

Other scientists question the validity of Tippett’s study, claiming that increased reporting and the prevalence of urban sprawl may be responsible for the perceived growth of tornado outbreaks. One critic is Howard Bluestein, a meteorology professor at the University of Oklahoma. He said, “It’s a useful exercise, but I would be very, very careful in accepting it.”

Seven people were killed by this week’s tornado cluster, several more were injured.

Precipitation in Iowa falls below average for first time since June


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Streamflow remains above average for much of northeastern Iowa as the state heads into the driest season of the year. (Iowa DNR)
Jenna Ladd | November 8, 2016

The Iowa Department of Natural Resources (DNR) recently released its latest Water Summary Update. Each update provides an overview of the status of Iowa’s water resources using four categories: precipitation, streamflow, drought, and shallow groundwater. The latest update provides a water resource snapshot of trends from October 10 through November 3.

As Iowa heads into the driest season of the year, stretching from November through February, October was recorded as the first month since June in which rainfall fell below normal levels. “Abnormally dry,” or drought conditions persisted for south-central Iowa, with the lowest reported October rainfall of 0.54 inches recorded in Story County. Areas of north central and northeastern Iowa, which had experienced heavy rainfall throughout much of September, saw drier conditions at last.

Temperatures throughout the month of October were warmer than they have been since 2007, averaging about 4.5 degrees above normal. This season’s first freeze is yet to occur for the Des Moines metro area, as well as far eastern and southeastern Iowa. The northwest two-thirds portion of the state experienced its first deep freeze on October 13.

Since the previous Water Summary Update, streamflow in the Chartion River Basin in south central Iowa has decreased to normal levels. However, streamflow for most of Iowa remains above average. More specifically, streamflow in the Cedar, Des Moines, and Upper Iowa River basins remain far above average. The forthcoming four months not only mark the driest season of the year, but also the most hydrologically stable. During this period of time Iowa usually receives about 15 percent of the year’s total rainfall, or 5.5 inches of precipitation. In contrast, summer months in the state bring more than 18 inches of precipitation on average.

Water Summary Updates are released every two weeks or as water resource conditions in Iowa significantly change. They are prepared by the Iowa DNR in partnership with Iowa Department of Agriculture and Land Stewardship, the U.S. Geological Survey, and The Iowa Homeland Security and Emergency Management Division. A complete record of Iowa Water Summary Updates can be found here.

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(Iowa DNR)

NOAA expects Iowa winter to be unpredictable


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Iowa falls between regions of the country that will a experience particularly  cold winter and those that will have a particularly warm winter. (NOAA)
Jenna Ladd | October 21, 2016

The National Oceanic and Atmospheric Administration (NOAA) released its predictions for winter weather on Thursday.

Last year the midwest experienced the warmest winter on record in 121 years, but this year NOAA says that Iowans can expect a grab bag of both warm and cold temperatures. Both temperature and precipitation are expected to hover around average from December through February for much of the state, except for the northern most part of the state, which is expected to be colder than usual.

NOAA also expects a weak La Niña this year. La Niña is characterized by particularly cold ocean temperatures in the Equatorial Pacific, and often affects weather trends in the United States. Variances in La Niña’s strength and duration from year to year can make forecasting winter temperatures difficult. Mike Halpert is deputy director with NOAA’s Climate Prediction Center, he said, “Because there is still some uncertainly about when La Niña will develop and persist through the winter, probabilities on the maps this year are fairly conservative.”

Winter 2015-2016 was the wettest Iowa winter on record in 101 years. Other parts of the Midwest and the Western U.S. are predicted to receive high amounts precipitation this year, with Idaho, North Dakota and the Ohio Valley all among those that will be affected. Unusually cool temperatures are on the forecast from Eastern Montana through Wisconsin.

In short, NOAA expects wetter and colder than usual temperatures for the far northern Midwest and warmer with drier winter conditions for the Southern U.S., and most of Iowa falls somewhere in the middle. Much like most winters, Iowans should prepare for anything.