Hurricane Dorian highlights growing vulnerability of islanders


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This map from NOAA shows Dorian passing over the Bahamas, forecasting its trajectory as of 11 a.m. Sunday, Aug. 31. 

Julia Poska | September 4, 2019

In recent years, the Caribbean islands have been repeatedly pummeled by unusually intense hurricanes. In 2017, Hurricanes Maria and Irma virtually destroyed Caribbean islands Dominicana and Barbuda. Puerto Rico is still recovering from devastation that same year. 

This week, Hurricane Dorian, the second strongest Atlantic storm on record, hit hard in the Bahamas. An aerial video from NBC reveals widespread flooding and buildings reduced to rubble on Abaco Island.

Once these islands recover, spending billions to do so, they can expect to see more intense storms in the future, as climate change increases the impacts of hurricanes. Though mitigation can be at least partially achieved through social and infrastructural means, many islands lack the financial means to implement them, as well as ample time between storms. 

Evacuation orders protect human life, but accessing transportation by air or water can be expensive, leaving inland shelters as the best option for many. In the Bahamans, 24 shelters were established inland on Abaco and Grand Bahamas Island, with 73,000 residents at risk, according to the Washington Post. The Bahamasair airline offered discounted flights off the island.

As climate change progresses, rising sea levels will make coastal flooding a permanent feature of island life, as well,  reducing inhabitable land and threatening freshwater resources within the islands. Just two degrees of warming would put Bahamian capital island Nassau and many smaller Caribbean islands almost completely underwater (see this map from Climate Central), forcing residents to relocate as “climate refugees.”

 

 

 

North Carolina policy increases state’s vulnerability to storms like Dorian


Photo by Pixabay on Pexels.com

Tyler Chalfant | September 3rd, 2019

As Hurricane Dorian hits the southeastern coast today, several of the states in its trajectory are particularly vulnerable due to policies that have ignored the reality of climate change. In North Carolina, lawmakers have limited the ability of scientists to make long-term predictions about sea level rise, and encouraged developments on the low-lying barrier islands which may make the shoreline more vulnerable.

Dorian has already been uniquely devastating to the Bahamas, where at least five people have been killed and as many as 13,000 homes destroyed. The hurricane slowed to a virtual standstill over the island, following the pattern of Hurricanes Harvey and Florence over the past two years. Warm water causes storms to move more slowly and intensify more quickly, so as the planet’s oceans and atmosphere warm, this trend is likely to continue. Dorian makes 2019 the fourth year in a row to have a category 5 hurricane, which is the longest streak on record. 

The barrier islands along the lower part of the North Carolina’s shoreline are being gradually pushed towards the mainland through natural erosion as sea levels rise. Recent tourist-driven developments, largely subsidized through the National Flood Insurance Program, attempt to hold the islands in place by replenishing depleted shorelines, making them more vulnerable to storms and to being washed over from both sides.
In 2012, the state’s Coastal Resources Commission chose to ignore its scientific advisors when they issued a report projecting 39 inches of sea level rise by the end of the century. Saying they wanted forecasts to be based on historical rates, the lawmakers placed a 30-year limit on the forecasts that could be made. As the science advisory panel prepares to update its sea level rise report later this year, this limitation may be removed.

Extreme weather costlier than ever in 2017


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Jenna Ladd | March 28, 2018

As the Northern Hemisphere enters warmer seasons where severe weather and flooding are more likely, it is yet to be seen whether 2018 will top 2017 as the most costly year for natural disasters ever.

Since 1980, the yearly average for natural disasters in the U.S. that cause more than $1 billion in damages has been 5.8 events. Last year, the country saw 16 such events, including three tropical cyclones, eight severe storms, two inland floods, a crop freeze, drought and wildfire. While this number technically ties with 2011, 2017 had more extreme weather as wildfires are tallied by region rather than single events, and last year brought more wildfires costing upwards of $1 billion than ever before.

According to NOAA’s National Centers for Environmental Information, the total cost of severe weather last year was $306.2 billion. This surpassed the previous record by nearly $100 billion dollars. Hurricanes Harvey, Irma and Maria caused $265.0 billion of 2017’s damages. Researchers figure physical damages to buildings and infrastructure as well as crop damages and losses to business into the total cost.

The midwest U.S. saw at least two severe storms last year that caused more than $1 billion in damages, both of them in mid-June. Flooding associated with storms like these has caused some $13.5 billion in economic losses from 1988 to 2015 in Iowa alone, according to a recent op-ed by Iowa Flood Center Director Witold Krajewski. Midwesterners also faced early tornado outbreaks in 2017, which tore across the region in late February and early March. Both events cause more than $1 billion in damages.

The National Centers for Environmental Information point out that increased development in vulnerable areas like coastlines, floodplains and fire-prone areas are causing the increase in billion dollar disasters. Climate change plays a role too. They write,

“Climate change is also paying an increasing role in the increasing frequency of some types of extreme weather that lead to billion-dollar disasters. Most notably the rise in vulnerability to drought, lengthening wildfire seasons and the potential for extremely heavy rainfall and inland flooding events are most acutely related to the influence of climate change.”

September 2017 record-setting month for hurricanes


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A satellite image of Hurricane Maria. (Sturart Rankin/flickr)

Jenna Ladd | October 4, 2017

September 2017 was a record-setting calendar month for hurricane activity in the Atlantic ocean.

The beginning of September brought Hurricane Harvey, a category four storm which caused unprecedented damage to the U.S.’s fourth largest city, Houston. Five additional hurricanes left paths destruction across the Caribbean and Florida later in September, with Irma and Maria both reaching category five status.

It is common for September to be the most active month for hurricanes because low pressure systems often move across the Atlantic from Africa and meet the tropical waters of the Caribbean at this time, but September 2017 was a cut above the rest. According to Phil Klotzbach of Colorado State University, September 2017 featured 18 “major hurricane days,” beating 1961’s record of 17.25 “major hurricane days.” Last month, the overall intensity and duration of storms, known as “accumulated cyclone energy,” was 175 units, significantly higher than September 2014’s record of 155 units.

While climate change has not been found to cause hurricanes, there is evidence to say that rising sea temperatures cause hurricanes to be more intense.

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 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.