Tag: aerosols

What caused ‘snowball Earth?’

Volcanoes seen as likely trigger for global glaciation

In the right conditions, global ice can spread rapidly from pole to pole. @bberwyn photo.

Staff Report

A 10-year string of steady volcanic eruptions may have been the trigger for a massive global cooling event that left much of the Earth encased in glaciers and ice sheets about 771 million years ago.

The eruptions could have spewed so much sulphur dioxide into the atmosphere that the planet’s climate reached a tipping point, resulting in what scientists call ‘snowball Earth,” according to a new study published this month in Geophysical Research Letters. Understanding the natural variability of climate is important to understanding current climate change driven by emission of greenhouse gases. Continue reading “What caused ‘snowball Earth?’”

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Droughts and fires affecting Western U.S. air quality

New study tracks increase in summertime haze in Colorado wilderness

Summit County firefighters extinguish a small wildfire between Keystone and Montezuma late March, 2012.
Summit County, Colorado, firefighters extinguish a small wildfire between Keystone and Montezuma late March, 2012. A new University of Utah study suggests that more drought and wildfires will worsen air pollution in the high country of the West, even spreading to pristine wilderness areas. @bberwyn photo.

Staff Report

Longer and hotter droughts and wildfires are polluting the once clear blue skies of the high country in the West, according to new research from the University of Utah.

The study, published this week in the journal Environmental Research Letters, found a link between the severity of drought in the Intermountain West and summertime air quality. Climate projections suggest that drought and wildfire risk will continue to increase in coming decades.

“If you take that into the future, we’re going to see significant hazing of the West,” said University of Utah atmospheric scientist Gannet Hallar. Continue reading “Droughts and fires affecting Western U.S. air quality”

Study eyes role of plankton in cloud formation

Southern Ocean research shows how plankton emissions brighten clouds

Clouds over Antarctica. @bberwyn photo.
Clouds over Antarctica. @bberwyn photo.

Staff Report

FRISCO — Swarms of tiny plankton may play a bigger role in cloud formation than previously realized, scientists said after studying the Southern Ocean.

The new research shows that plankton produce airborne gases and organic matter to seed cloud droplets, which lead to brighter clouds that reflect more sunlight. Continue reading “Study eyes role of plankton in cloud formation”

Climate: Do cities trigger their own weather?

Study tracks increased thunderstorm formation over Atlanta

A classic anvil-headed cumulunimbus cloud drops showers just east of the Continental Divide near Grays and Torreys Peak Tuesday evening. We haven't had a chance to see these beautiful clouds recently because we've been right underneath them. Click on the image to learn more about thundercloud formation.
A classic anvil-headed cumulunimbus cloud drops showers just east of the Continental Divide near Grays and Torreys Peak in Colorado.

Staff Report

FRISCO — Along with steadily raising global temperatures in the long-term, human-caused changes in land cover can affect day-to-day weather, including the formation of thunderstorms.

Specifically, urban areas appear to help trigger the formation of thunderstorms, possibly due to an increased concentration of aerosols, according to new research published in the Quarterly Journal of the Royal Meteorological Society. Continue reading “Climate: Do cities trigger their own weather?”

Do small volcanoes have a big climate impact?

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New research may help explain the overall effect of volcanoes on global climate. Photo courtesy USGS.

New research tracks aerosols from volcanic eruptions

Staff Report

FRISCO — Sunlight-reflecting particles from relatively small volcanic eruptions may add up to have a significant effect on global temperatures, according to a new climate study that tries to quantify the cumulative impact of aerosols from volcanoes.

According to the research, based on a combination of measurements taken on the ground, in the air and from satellites, small volcanic eruptions that occurred between 2000 and 2013 deflected almost double the amount of solar radiation previously estimated.

That’s enough to lower global temperatures by about  0.05 to 0.12 degrees Celsius, the scientists concluded in their study, which appears in Geophysical Research Letters. Continue reading “Do small volcanoes have a big climate impact?”

Climate: Pollution causing drop in monsoon rains

A classic monsoonal flow of moisture, moving clockwise around a
A classic North American monsoonal flow of moisture, moving clockwise around an area of high pressure.

‘Human activity has played a significant role in altering the seasonal monsoon rainfall on which billions of people depend’

Staff Report

FRISCO — A 10 percent drop in overall monsoon rainfall in the northern hemisphere during past 50 years is outside the range of natural climate variability, Scottish researchers said after a detailed analysis of weather data.

After accounting for all the variables, the scientists said that emissions produced by human activity caused the drop. Tiny air particles from man-made sources — known as anthropogenic aerosols — were the cause. Continue reading “Climate: Pollution causing drop in monsoon rains”

Climate: Bioparticles in dusty air may be key to rain and snow formation

Tiny bioparticles in atmospheric dust play a big role in the formation of raindrops and snowflakes. bberwyn photo.
Tiny bioparticles in atmospheric dust play a big role in the formation of raindrops and snowflakes. bberwyn photo.

Researchers starting to take nuanced look at chemical composition of aerosols

Staff Report

FRISCO —Scientists have long known that tiny grains of airborne dust are key players in the formation of rain and snow, driving precipitation patterns across the drought-stricken western U.S. and other areas.

New research suggests that  the exact chemical make-up of that dust, including microbes found in it, is the key to how much rain and snow falls from clouds.  The information could help better predict rain events, as well as explain how air pollution from a variety of sources influences regional climate in general.

“We’ve learned that not all of the particles in the air at high altitudes have the same influence on clouds. We’re starting to think that these differences contribute to how rain gets distributed,” said Dr. Kim Prather, who presented her findings at the 248th National Meeting & Exposition of the American Chemical Society last week in San Francisco. Continue reading “Climate: Bioparticles in dusty air may be key to rain and snow formation”