Hailstorms inflict billions of dollars’ worth of damage yearly in North America alone, and the cost will rise as the growing population builds more homes, offices and factories, climate and weather experts said Tuesday.
The role of climate change in hailstorms is harder to assess, the experts said at a conference at the National Center for Atmospheric Research in Boulder, Colorado.
Climate change will most likely make large hailstorms worse, but population growth is more of a certainty, said Andreas Prein, a climate modeling scientist at the atmospheric research center.
“We know pretty certain that we will have more people in the future, and they will have more stuff, and this stuff can be damaged,” Prein said. “I think this component is more certain than what we can say about climate change at the moment.”
This year is expected to be the 11th in a row in which the damage from severe storms exceeds $10 billion in the United States, and 70 percent of that cost comes from hail, said Ian Giammanco, a research meteorologist for the Insurance Institute for Business and Home Safety.
“It’s such a huge driver of the dollar loss each year,” he said.
Bigger homes, closer together
Costs are rising in the U.S. because homes are getting bigger, from about 1,700 square feet (139 square meters) in the early 1980s to 2,500 square feet (232 square meters) in 2015, he said. New subdivisions also pack homes in more tightly, Giammanco said.
“So it’s a bigger target for hailstorms to hit,” he said.
The effects of climate change on hail and the resulting damage are harder to calculate because hailstorms require distinct ingredients, and global warming affects them in different ways, Prein said.
To form, hailstorms require moisture, an updraft, variable winds and freezing temperatures at lower levels of the storm cloud, he said.
Updrafts lift water droplets into the clouds, where they attract other droplets and freeze together, scientists say. Winds of varying speed and direction keep the droplets suspended in the cloud long enough to grow into hailstones. When they eventually fall, freezing temperatures in the cloud keep them from melting before they hit warmer air closer to the ground.
Climate change will most likely increase updrafts, helping hailstones form, Prein said.
But it will inhibit two hail-producing conditions, he said. Warmer temperatures will expand higher into the atmosphere, so falling hailstones have more time to melt before hitting the ground. And differences in wind speed and direction will subside, he said.
Climate change will make the atmosphere more moist, but the effect that will have on hailstones isn’t clear, he said.
More storms that are severe
Kristen Rasmussen, an assistant professor at Colorado State University, said the combined effects of climate change will probably inhibit the number of weaker storms but increase the number of severe ones.
“So we actually think that’s why we’re seeing a decrease in the number of weak to moderate storms and an increase in the most severe storms,” she said. “If those storms are able to break through this inhibition, they … have the potential to be more severe, and they can tap into more energy when they do so.”
The researchers said they need more data to understand the relationship between climate change and hailstorms. Improved science could also help predict hailstorms and calculate risks better, they said.
The Rocky Mountains of Colorado, the Andes in South America and the Himalayas all have conditions that make them hot spots for hail, Rasmussen said.
A May 2017 hailstorm in the Denver area caused $2.3 billion in insurance losses. Last week, hail injured 14 people in Colorado Springs and killed at least five animals at the city zoo. Damage estimates were still being compiled.(VOA)
A staple of summer — swarms of bugs — seems to be a thing of the past. And that’s got scientists worried.
Pesky mosquitoes, disease-carrying ticks, crop-munching aphids and cockroaches are doing just fine. But the more beneficial flying insects of summer — native bees, moths, butterflies, ladybugs, lovebugs, mayflies and fireflies — appear to be less abundant.
Scientists think something is amiss, but they can’t be certain: In the past, they didn’t systematically count the population of flying insects, so they can’t make a proper comparison to today. Nevertheless, they’re pretty sure across the globe there are fewer insects that are crucial to as much as 80 percent of what we eat.
Yes, some insects are pests. But they also pollinate plants, are a key link in the food chain and help decompose life.
“You have total ecosystem collapse if you lose your insects. How much worse can it get than that?” said University of Delaware entomologist Doug Tallamy. If they disappeared, “the world would start to rot.”
He noted Harvard biologist E.O. Wilson once called bugs: “The little things that run the world.”
The 89-year-old Wilson recalled that he once frolicked in a “Washington alive with insects, especially butterflies.” Now, “the flying insects are virtually gone.”
It hit home last year when he drove from suburban Boston to Vermont and decided to count how many bugs hit his windshield. The result: A single moth.
The un-scientific experiment is called the windshield test. Wilson recommends everyday people do it themselves to see. Baby Boomers will probably notice the difference, Tallamy said.
Several scientists have conducted their own tests with windshields, car grilles and headlights, and most notice few squashed bugs. Researchers are quick to point out that such exercises aren’t good scientific experiments, since they don’t include control groups or make comparisons with past results. (Today’s cars also are more aerodynamic, so bugs are more likely to slip past them and live to buzz about it.)
Still, there are signs of decline. Research has shown dwindling individual species in specific places, including lightning bugs, moths and bumblebees. One study estimated a 14 percent decline in ladybugs in the United States and Canada from 1987 to 2006. University of Florida urban entomologist Philip Koehler said he’s seen a recent decrease in lovebugs — insects that fly connected and coated Florida’s windshields in the 1970s and 1980s. This year, he said, “was kind of disappointing, I thought.”
University of Nevada, Reno, researcher Lee Dyer and his colleagues have been looking at insects at the La Selva Biological Station in Costa Rica since 1991. There’s a big insect trap sheet under black light that decades ago would be covered with bugs. Now, “there’s no insects on that sheet,” he said.
But there’s not much research looking at all flying insects in big areas.
Last year, a study that found an 82 percent mid-summer decline in the number and weight of bugs captured in traps in 63 nature preserves in Germany compared with 27 years earlier. It was one of the few, if only, broad studies. Scientists say similar comparisons can’t be done elsewhere because similar bug counts weren’t done decades ago.
“We don’t know how much we’re losing if we don’t know how much we have,” said University of Hawaii entomologist Helen Spafford.
The lack of older data makes it “unclear to what degree we’re experiencing an arthropocalypse,” said University of Illinois entomologist May Berenbaum. Individual studies aren’t convincing in themselves, “but the sheer accumulated weight of evidence seems to be shifting” to show a problem, she said.
After the German study, countries started asking if they have similar problems, said ecologist Toke Thomas Hoye of Aarhus University in Denmark. He studied flies in a few spots in remote Greenland and noticed an 80 percent drop in numbers since 1996.
“It’s clearly not a German thing,” said University of Connecticut entomologist David Wagner, who has chronicled declines in moth populations in the northeastern United States. “We just need to find out how widespread the phenomenon is.”
Most scientists say lots of factors, not just one, caused the apparent decline in flying insects.
Suspects include habitat loss, insecticide use, the killing of native weeds, single-crop agriculture, invasive species, light pollution, highway traffic and climate change.
“It’s death by a thousand cuts, and that’s really bad news,” Wagner said.
To Tallamy, two causes stand out: Humans’ war on weeds and vast farmland planted with the same few crops.
Weeds and native plants are what bugs eat and where they live, Tallamy said. Milkweeds, crucial to the beautiful monarch butterfly, are dwindling fast. Manicured lawns in the United States are so prevalent that, added together, they are as big as New England, he said.
Those landscapes are “essentially dead zones,” he said.
Light pollution is another big problem for species such as moths and fireflies, bug experts said. Insects are attracted to brightness, where they become easy prey and expend energy they should be using to get food, Tallamy said.
Jesse Barber of Boise State is in the middle of a study of fireflies and other insects at Grand Teton National Park. He said he notices a distinct connection between light pollution and dwindling populations.
“We’re hitting insects during the day, we’re hitting them at night,” Tallamy said. “We’re hitting them just about everywhere.”
Lawns, light pollution and bug-massacring highway traffic are associated where people congregate. But Danish scientist Hoye found a noticeable drop in muscid flies in Greenland 300 miles (500 kilometers) from civilization. His studies linked declines to warmer temperatures.
Other scientists say human-caused climate change may play a role, albeit small.
Governments are trying to improve the situation. Maryland is in a three-year experiment to see if planting bee-friendly native wildflowers helps.
University of Maryland entomology researcher Lisa Kuder says the usual close-crop “turf is basically like a desert” that doesn’t attract flying insects. She found an improvement — 70 different species and records for bees — in the areas where flowers are allowed to grow wild and natural alongside roads.
The trouble is that it is so close to roadways that Tallamy fears that the plants become “ecological traps where you’re drawing insects in and they’re all squashed by cars.”
Still, Tallamy remains hopeful. In 2000, he moved into this rural area between Philadelphia and Baltimore and made his 10-acre patch all native plants, creating a playground for bugs. Now he has 861 species of moths and 54 species of breeding birds that feed on insects.
Wagner, of the University of Connecticut, spends his summers teaching middle schoolers in a camp to look for insects, like he did decades ago. They have a hard time finding the cocoons he used to see regularly.
“The kids I’m teaching right now are going to think that scarce insects are the rule,” Wagner said. “They’re not realizing that there could be an ecological disaster on the horizon.” (VOA)