Increasing tornado outbreaks — Is climate change responsible?

Tornadoes and severe thunderstorms kill people and damage property every year. Estimated U.S. insured losses due to severe thunderstorms in the first half of 2016 were $8.5 billion. The largest U.S. impacts of tornadoes result from tornado outbreaks, sequences of tornadoes that occur in close succession. Last spring a research team led by Michael Tippett, associate professor of applied physics and applied mathematics at Columbia Engineering, published a study showing that the average number of tornadoes during outbreaks—large-scale weather events that can last one to three days and span huge regions—has risen since 1954. But they were not sure why.

In a new paper, published December 1 in Science via First Release, the researchers looked at increasing trends in the severity of tornado outbreaks where they measured severity by the number of tornadoes per outbreak. They found that these trends are increasing fastest for the most extreme outbreaks. While they saw changes in meteorological quantities that are consistent with these upward trends, the meteorological trends were not the ones expected under climate change.

Corals much older than previously thought

Coral genotypes can survive for thousands of years, possibly making them the longest-lived animals in the world, according to researchers at Penn State, the National Marine Fisheries Service and Dial Cordy & Associates.

The team recently determined the ages of elkhorn corals  — Acropora palmata — in Florida and the Caribbean and estimated the oldest genotypes to be over 5,000 years old. The results are useful for understanding how corals will respond to current and future environmental change.

Bioenergy grass can withstand freezing temperatures

March 2012 was unusually warm. Biomass crops around the Midwest were well established and thriving. But when a late frost came in mid-April, all of that changed.

“When I went out in the morning, I was just shocked,” says University of Illinois agronomist D.K. Lee. “All the grasses were covered in frost. By noon, Miscanthus and switchgrass had turned black. The only plant that was untouched was prairie cordgrass.”

Climate models may be overestimating the cooling effect of wildfire aerosols

Whether intentionally set to consume agricultural waste or naturally ignited in forests or peatlands, open-burning fires impact the global climate system in two ways which, to some extent, cancel each other out. On one hand, they generate a significant fraction of the world’s carbon dioxide emissions, which drive up the average global surface temperature. On the other hand, they produce atmospheric aerosols, organic carbon, black carbon, and sulfate-bearing particulates that can lower that temperature either directly, by reflecting sunlight skyward, or indirectly, by increasing the reflectivity of clouds. Because wildfire aerosols play a key role in determining the future of the planet’s temperature and precipitation patterns, it’s crucial that today’s climate models — upon which energy and climate policymaking depend — accurately represent their impact on the climate system.

With Climate Change, Not All Wildlife Population Shifts Are Predictable

Wildlife ecologists who study the effects of climate change assume, with support from several studies, that warming temperatures caused by climate change are forcing animals to move either northward or upslope on mountainsides to stay within their natural climate conditions.

But a new study of lowland and higher-mountain bird species by wildlife ecologists Bill DeLuca and David King at the University of Massachusetts Amherst now reports an unexpected and “unprecedented” inconsistency in such shifts. The majority of the mountain bird community responded against expectation and shifted downslope despite warming trends in the mountains. They say the result “highlights the need for caution when applying conventional expectations to species’ responses to climate change.”

Groundwater helium level could signal potential risk of earthquake

Researchers at the University of Tokyo and their collaborators have revealed a relationship between helium levels in groundwater and the amount of stress exerted on inner rock layers of the earth, found at locations near the epicenter of the 2016 Kumamoto earthquake. Scientists hope the finding will lead to the development of a monitoring system that catches stress changes that could foreshadow a big earthquake.

Several studies, including some on the massive earthquake in Kobe, Japan, in 1995, have indicated that changes to the chemical makeup of groundwater may occur prior to earthquakes. However, researchers still needed to accumulate evidence to link the occurrence of earthquakes to such chemical changes before establishing a strong correlation between the two.

Can Road Salt Change Sex Ratios in Frog Populations?

Naturally occurring chemicals found in road salts commonly used to de-ice paved surfaces can alter the sex ratios in nearby frog populations, a phenomenon that could reduce the size and viability of species populations, according to a new study by scientists at Yale and Rensselaer Polytechnic Institute (RPI).

West Antarctic ice shelf breaking up from the inside out

A key glacier in Antarctica is breaking apart from the inside out, suggesting that the ocean is weakening ice on the edges of the continent.

The Pine Island Glacier, part of the ice shelf that bounds the West Antarctic Ice Sheet, is one of two glaciers that researchers believe are most likely to undergo rapid retreat, bringing more ice from the interior of the ice sheet to the ocean, where its melting would flood coastlines around the world.

A nearly 225-square-mile iceberg broke off from the glacier in 2015, but it wasn’t until Ohio State University researchers were testing some new image-processing software that they noticed something strange in satellite images taken before the event.

102 Million Trees Have Died in California's Drought

California’s six years of drought has left 102 million dead trees across 7.7 million acres of forest in its wake, the U.S. Forest Service (USFS) announced following an aerial survey. If that is not horrendous enough, 62 million trees died in the year 2016 alone—an increase of more than 100 percent compared to 2015.

“The scale of die-off in California is unprecedented in our modern history,” Randy Moore, a forester for the U.S. Forest Service, told the Los Angeles Times, adding that trees are dying “at a rate much quicker than we thought.”

Study Shows Climate Affecting Avian Breeding Habits

Milder winters have led to earlier growing seasons and noticeable effects on the breeding habits of some predatory birds, according to research by Boise State biologists Shawn Smith and Julie Heath, in collaboration with Karen Steenhof, and The Peregrine Fund’s Christopher McClure. Their work was recently published in the Journal of Animal Ecology under the title “Earlier nesting by generalist predatory bird is associated with human responses to climate change.”