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Trees Save Big Cities $500 Million Each Year

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As if you really needed another reason to hug a tree: Scientists writing in the journal Ecological Modeling say trees in big cities deliver more than $500 million in environmental benefits every year.

A tree is a marvel of biology. Unfussed by the pull of gravity, it sucks water upward; unembarrassed by its resourcefulness, it makes food out of the waste gases we leave behind. And that’s just what it does for itself; for us, it does even more, cleaning our air, beautifying our neighborhoods, improving our health and well-being, reducing our energy use, and helping us beat the heat.

"Trees have direct and indirect benefits for cooling buildings and reducing human suffering during heat waves," lead author Theodore Endreny of the SUNY College of Environmental Science and Forestry said in a statement. "The direct benefit is shade which keeps the urban area cooler, the indirect benefit is transpiration of stormwater which turns hot air into cooler air."

Endreny and his colleagues wondered how these qualitative effects might translate into dollars, or rubles, or rupees. The researchers used a tool called i-Tree Eco to estimate the amount of tree cover in 10 huge cities: Beijing, Buenos Aires, Cairo, Istanbul, London, Los Angeles, Mexico City, Moscow, Mumbai, and Tokyo.

These densely packed megacities are home to almost 10 percent of the entire human population of Earth—people whose lives often depend on natural environments outside city limits.

“What is, however, most often disregarded,” the authors note, “is that nature conservation in the city can also contribute to human well-being benefits. The most common mind set separates cities from the rest of nature, as if they were not special kinds of natural habitats.”

Their results showed that those urban natural habitats occupied about 21 percent of each megacity landscape. That’s a lot of tree cover, but there could be a lot more; on average, the researchers found another 19 percent of land that could be given over to vegetation.

The data suggested that filling this space with trees could increase environmental and cost benefits by an average of 85 percent.

As they are now, the trees are already saving megacities gobs and gobs of money—about $1.2 million per square mile, or $35 per resident, per year.

"Placing these results on the larger scale of socioeconomic systems makes evident to what extent nature supports our individual and community well-being by providing ecosystem services for free," co-author Sergio Ulgiati of Italy’s University Parthenope said in the statement.

"A deeper awareness of the economic value of free services provided by nature may increase our willingness to invest efforts and resources into natural capital conservation and correct exploitation, so that societal wealth, economic stability and well-being would also increase."

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Philippe Huguen, AFP/Getty Images
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environment
McDonald's May Be Getting Rid of Its Plastic Straws
Philippe Huguen, AFP/Getty Images
Philippe Huguen, AFP/Getty Images

First Seattle and then the Queen. Could the Golden Arches be next to join the anti-straw movement? As Fortune reports, McDonald's shareholders will vote at their annual meeting on May 24 on a proposal to phase out drinking straws at the company's 37,000-plus locations in the U.S.

If passed, the fast food behemoth would join the ranks of other governments and businesses around the world that have enacted bans against straws in an effort to reduce plastic waste. Straws are notoriously hard to recycle and typically take hundreds of years to decompose.

McDonald's is currently in the process of removing plastic straws from its roughly 1300 outlets in the UK. However, McDonald's board of directors opposes the move in the U.S., arguing that it would divert money from the company's other eco-friendly initiatives, The Orange County Register reports. This echoes comments from the plastic industry, which says efforts should instead be focused on improving recycling technologies.

"Bans are overly simplistic and may give consumers a false sense of accomplishment without addressing the problem of litter," Scott DeFife of the Plastics Industry Association told the Daily News in New York City, where the city council is mulling a similar citywide ban.

If the city votes in favor of a ban, they'd be following in the footsteps of Seattle, Miami Beach, and Malibu, California, to name a few. In February, Queen Elizabeth II was inspired to ban straws at royal palaces after working with David Attenborough on a conservation film. Prime Minister Theresa May followed suit, announcing in April that the UK would ban plastic straws, cotton swabs, and other single-use plastic items.

It's unclear how many straws are used in the U.S. By one widely reported estimate, Americans use 500 million disposable straws per day—or 1.6 straws per person—but it has been noted that these statistics are based on a survey conducted by an elementary school student. However, plastic straws are the fifth most common type of trash left on beaches, according to data reported by Fortune.

[h/t Fortune]

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Mario Tama, Getty Images
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Hawaii's Kilauea Volcano Is Causing Another Explosive Problem: Laze
Mario Tama, Getty Images
Mario Tama, Getty Images

Rivers of molten rock aren't the only thing residents near Hawaii's Kilauea volcano have to worry about. Lava from recent volcanic activity has reached the Pacific Ocean and is generating toxic, glass-laced "laze," according to Honolulu-based KITV. Just what is this dangerous substance?

Molten lava has a temperature of about 2000°F, while the surrounding seawater in Hawaii is closer to 80°F. When this super-hot lava hits the colder ocean, the heat makes the water boil, creating powerful explosions of steam, scalding hot water, and projectile rock fragments known as tephra. These plumes are called lava haze, or laze.

Though it looks like regular steam, laze is much more dangerous. When the water and lava combine, and hot lava vaporizes seawater, a series of reactions causes the formation of toxic gas. Chloride from the sea salt mixes with hydrogen in the steam to create a dense, corrosive mixture of hydrochloric acid. The vapor forms clouds that then turn into acid rain.

Laze blows out of the ocean near a lava flow
USGS

That’s not the only danger. The lava cools down rapidly, forming volcanic glass—tiny shards of which explode into the air along with the gases.

Even the slightest encounter with a wisp of laze can be problematic. The hot, acidic mixture can irritate the skin, eyes, and respiratory system. It's particularly hazardous to those with breathing problems, like people with asthma.

In 2000, two people died in Hawaii Volcanoes National Park from inhaling laze coming from an active lava flow.

The problem spreads far beyond where the lava itself is flowing, pushing the problem downwind. Due to the amount of lava flowing into the ocean and the strength of the winds, laze currently being generated by the Kilauea eruptions could spread up to 15 miles away, a USGS geologist told Reuters.

[h/t Forbes]

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