Greenland’s Melting Ice Could Be Triggering Mountain Collapses


Melting Arctic ice isn't just bad news for sea levels. In Greenland, ice that previously held mountains together is melting, shaking loose unstable rock, according to New Scientist. That triggers huge landslides, which in turn leads to deadly tsunamis.

In June, 39 people were evacuated and several were killed after a tsunami flooded the remote island of Nuugaatsiaq, Greenland. Initially, authorities thought the tsunami was the result of a 4.1 earthquake off the coast. But it turned out that it wasn't an earthquake at all. The tsunami was triggered by part of a mountain collapsing, creating a giant landslide of seismic proportions that fell into the sea.

As the world gets warmer, we may have to deal with more incidents like these. Where previously ice might have been able to hold together the unstable rock of a mountain, if that ice melts, there's nothing to keep that rock from coming down. As a glaciologist told New Scientist, the melting and freezing cycles of ice in Greenland have created a dire situation.

Greenland and other fjord-dominated landscapes are at high risk for these sorts of disasters as ice melts. The sharp, steep cliffs of fjords make it easy for unstable rocks to go tumbling into deep water, causing dangerously strong waves. These tsunamis can reach speeds of more than 500 miles per hour. The deeper the water that the mountain collapses into, the stronger the tsunami, which means more bad news from rising sea levels.

[h/t New Scientist]

Britain Is in the Midst of a Rare ‘Wind Drought’


Generating renewable energy in Britain is a little less than a breeze these days: A “wind drought” is halting the country’s wind turbines.

This month’s wind energy output is down 40 percent from the same time last year, New Scientist reports. On average, about 15 percent of Britain’s electricity comes from wind power. Data starting from July 1 of this year put the monthly average closer to 6.9 percent. Last month, turbines were producing less than 2 percent of Britain’s electricity—the lowest output in two years.

That’s with even more wind turbines being installed over the course of the past year, New Scientist says. The data aren’t entirely surprising, though. The jet stream tends to make the UK’s weather drier and calmer during the summer and wetter and stormier during the winter. But the high pressure the jet stream has brought with it this year has been unusually prolonged, scientists say.

“It’s like a lid, it keeps everything still,” UK Met Office spokesperson Grahame Madge told New Scientist. “From the forecast looking out over the next couple of weeks, there doesn’t seem to be any significant change on the way.”

The wind drought shouldn’t cause too many problems in the short term. Electricity demand is low during the summer (very few British homes have air conditioning), and the country’s been able to compensate for the lack of wind by burning more natural gas. If the wind drought continues to persist, though, UK residents may begin to see an increase in utility fees. Natural gas prices have already risen with the increased demand.

“As we continue to transition to a low-carbon energy system, managing the intermittency of renewable power an important role in balancing supply and demand,” a National Grid spokesperson told New Scientist. “However, we have planned for these changes and [are] ready to play our part.”

The wind drought comes about eight years after British politicians vowed to reduce the UK's dependence on fossil fuels. Last year was the first year that electricity generated from low-carbon energy sources like solar power, wind power, and nuclear power outpaced high-carbon energy sources like coal and natural gas. This summer’s wind drought may make it difficult to improve on last year’s numbers.

[h/t New Scientist]

Why Does the Sky Look Green Before a Tornado?


A common bit of folklore from tornado-prone parts of the U.S. says that when the skies start taking on an emerald hue, it's time to run inside. But why do tornadoes tend to spawn green skies in the first place? As SciShow's Michael Aranda explains, the answer has to do with the way water droplets reflect the colors of the light spectrum.

During the day, the sky is usually blue because the shorter, bluer end of the light spectrum bounces off air molecules better than than redder, longer-wavelength light. Conditions change during the sunset (and sunrise), when sunlight has to travel through more air, and when storms are forming, which means there are more water droplets around.

Tornadoes forming later in the day, around sunset, do a great job of reflecting the green part of the light spectrum that's usually hidden in a sunset because of the water droplets in the clouds, which bounce green light into our eyes. But that doesn't necessarily mean a twister is coming—it could just mean a lot of rain is in the forecast. Either way, heading inside is probably a good idea.

For the full details on how water and light conspire to turn the sky green before a storm, check out the SciShow video below.


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