Climate Change, Nature, Science

Global Warming Hiatus? Not So Much

The "global warming hiatus" really wasn't. Read more in this post.
Arctic glaciers. Photo: Shutterstock

New data from the University of Alaska Fairbanks shows that missing Arctic temperature data, not the climate, created the seeming “pause” of global warming from 1998 to 2012.

In fact, the improved datasets the researchers gathered shows that the Arctic warmed six times faster than the global average during the so-called global warming hiatus.

Atmospheric scientist Xiangdong Zhang collaborated with colleagues at Tsinghua University in Beijing and Chinese agencies studying Arctic warming to analyze temperature data collected from buoys in the Arctic Ocean.

“We recalculated the average global temperatures from 1998 to 2012 and found that the rate of global warming had continued to rise at 0.112 degrees C per decade instead of slowing down to 0.05 degrees C per decade as previously thought,” Zhang said.

How did the data lead scientists down the wrong path before?

Most current estimates use global data that represents a long timespan and provides good coverage of a global geographic area. But the Arctic, being so remote, lacks a comprehensive network of instruments to collect accurate temperature data.

To improve the dataset, Zhang’s team relied on temperature data collected from the International Arctic Buoy Program at the University of Washington. For global data, the team used newly corrected sea surface temperatures provided by the National Oceanic and Atmospheric Administration. By doing so, the team was able to re-estimate the average global temperatures during that time with more accurate and representative data.

The global warming hiatus is a hotly debated topic among climate scientists. Some say that an unusually warm El Niño in 1997-1998, followed by an extended period afterward that didn’t have an El Niño may have disrupted global warming.

It was a nice dream, but unfortunately, the new data sets and resulting estimates prove conclusively that global warming did not pause at all. Not only that, but until recently, scientists didn’t consider the Arctic big enough to greatly influence global temperatures.

“The Arctic is remote only in terms of physical distance,” Zhang said. “In terms of science, it’s close to every one of us. It’s a necessary part of the equation and the answer affects us all.”

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Environmental Hazards, Science

Scientists Find New Way to Process Radioactive Waste

The question of what to do with radioactive waste may have been solved by a team of Japanese scientists.
The question of what to do with radioactive waste may have been solved by a team of Japanese scientists. Photo: Shutterstock

Ever since the first atomic bomb was exploded during World War II’s Manhattan Project, and ever since the first nuclear power plant opened in Obninsk, Russia, radioactive waste has been accumulating. As the number of nuclear power plants and nuclear weapon plants increased, the question of what to do with all that waste has become one of the biggest issues facing science today.

The primary issue is what to do with radioactive waste after the uranium and plutonium have been recovered from spent nuclear fuel using standard reprocessing methods such as Plutonium Uranium Redox Extraction (PUREX).

Up until now, the most viable option for disposal of nuclear waste has been burying it deep underground. Other solutions such as partitioning and transmuting, which involve separating nuclear fuel into minor actinides such as neptunium, americium, and curium, have proven to be costly and cumbersome because of the need to separate isotopes before they can undergo transmutation. But now, a team of researchers at Tokyo Institute of Technology may have come up with a solution to the radioactive waste problem.

The team discovered a method of dramatically reducing the effective half-life of long-lived fission products (LLFPs) such as selenium-79, zirconium-93, technetium-99, palladium-107, iodine-129, and caesium-135. That method involves transmuting these isotopes in fast-spectrum reactors, which don’t need isotope separation like other methods do.

By adding a moderator (slowing-down material) called Yttrium deuteride (YD2), the team found that LLFP transmutation efficiency increased in the radial blanket and shield regions of the reactor. The researchers say this increased effectiveness is due to the moderator’s ability “to soften the neutron spectrum leaking from the core.”

Using this method, the researchers say, the 17,000 tons of LLFPs in Japan could potentially be disposed of by using 10 fast spectrum reactors. This method also has the advantage of contributing to electricity generation and supporting efforts toward nuclear non-proliferation.

Although ultimately, the best solution to the nuclear waste problem is to invest in non-toxic energy sources like solar and wind power, it’s a good thing these researchers came up with a way to decrease the toxicity of radioactive waste and give its by-products a new life—and a much shorter half-life.

carbon emissions, emissions, Science

Moving Bus Stops Could Reduce Pollution Exposure

Moving bus stops 120 feet from intersections can drastically reduce the amount of pollutants bus commuters are exposed to.
Passengers board an MTA bus in New York. Moving that stop away from the intersection could reduce the pollution to which transit commuters are exposed. Photo: Roman Tiraspolsky / Shutterstock.com

There’s no doubt that mass transit can make a huge difference in the overall air quality of cities. An increasing number of people are realizing that they can reduce their carbon footprint by riding a bus to and from work rather than being stuck in traffic in a car.

There’s just one problem with riding the bus, and that’s waiting for the bus.

Research has shown that in many cities in the United States and internationally, bus riders could spend 15 to 25 minutes each way waiting for a bus. This isn’t just a convenience issue; it’s a pollution exposure issue, too.

“The wait often means spending time in some of the most polluted locations in cities, close to intersections where cars, trucks, and buses are continually stopping and accelerating, spewing out high concentrations of noxious exhaust,” said Suzanne Paulson of UCLA, senior author of an article that appeared recently in the journal Environmental Pollution. “The exhaust contains gases and large amounts of ultrafine particles that are essentially unregulated by the Environmental Protection Agency because the EPA regulates fine particles by weight, and these particles weigh so little.”

The good news, according to the researchers, is that moving bus and light rail stops to locations 120 feet from intersections can significantly reduce the amount of pollutants to which bus commuters are exposed.

The researchers came to their conclusions by using a zero-emission vehicle equipped with instruments that measure ultrafine particles and tailpipe pollutants like carbon monoxide and nitrogen oxide. The studies were conducted in several neighborhoods in and around Los Angeles, over a 15-day period from summer into late fall in 2013 and over four days in the summer of 2014.

“We then combined and analyzed the data for each intersection to create high-resolution maps of pollutant concentrations along blocs,” said study lead author Wonsik Choi.

“Except in areas with minimal traffic, we always found there would be a significant reduction [of pollutants],” said Choi.

Traffic engineers believe that traffic flows better if bus stops are located after intersections rather than before. Better traffic flow can lead to less stop-and-go traffic, which would also improve air quality. The researchers caution that although moving the stops 120 feet from the end of a block will improve transit users’ pollution exposure, as long as that distance doesn’t put the bus stop in range of pollution from the next street.

Considering that most city blocks are about generally about 400 by 400 feet in size, it seems like it should be easy to move bus stops 120 feet away from intersections. That doesn’t mean buses won’t park all along a block where a stop is located, but it does mean that theoretically, passengers waiting for their bus will be able to do so in an area that exposes them to fewer pollutants.

Nature, oceans

New Study Says Sea Animals Eat Plastic Because of Its Taste

A new study says that sea animals may like plastic because it tastes good.
These coral polyps are feeding–and most likely ingesting lots of microplastics in the process. Photo: Shutterstock

Scientists have long known that plastic in the oceans can mimic prey, causing huge problems for sea life. But what they didn’t know is that even corals eat plastic.

Corals don’t have eyes, and they don’t move from their location, so why would they eat plastic? Apparently because it tastes good, according to a recent study from Duke University.

This taste factor may also be true for other sea life. After all, anecdotal evidence suggests that our cats and dogs eat plastic because they like the taste and/or the texture, so why wouldn’t sea life have the same reaction?

Microplastics, tiny pieces of weathered plastic less than 5 millimeters in diameter, have been accumulating in the world’s oceans for 40 years or more, and now they’re ubiquitous in the marine environment. They don’t just pose threats to corals, they also pose a threat to foraging sea animals including birds, turtles, mammals, and invertebrates.

Because plastic is largely indigestible, it can lead to intestinal blockages, create a false sense of fullness, or reduce energy reserves in animals that eat it.

“About eight percent of the plastic that coral polyps in our study ingested was still stuck in their guts after 24 hours,” said study co-lead author Austin S. Allen, a Ph.D. student at Duke.

Plastics can also leach hundreds of chemical compounds into the bodies of the creatures that eat it and into the environment as well. The biological effects of most plastic compounds are unknown, but we do know that some have already been shown to cause harm. For example, phthalates are confirmed environmental estrogens and androgens—that is, hormones that affect sex determination.

“Corals in our experiments ate all types of plastics, but preferred unfouled microplastics by a threefold difference over microplastics covered in bacteria,” Allen said.

“When plastic comes from the factory, it has hundreds of chemical additives on it. Any one of these chemicals or a combination of them could be acting as a stimulant that makes plastic appealing to corals,” said Alexander C. Seymour, a GIS analyst at Duke, who co-led the study with Allen.

The researchers hope their findings will encourage more scientists to study the role taste plays in determining why marine animals ingest microplastics.

“Ultimately, the hope is that if we can manufacture plastic so it unintentionally tastes good to these animals, we might also be able to manufacture it so it intentionally tastes bad,” Seymour said. “That could significantly help reduce the threat these microplastics pose.”

Environmental Hazards, Science

Road Pricing Could Be the Most Effective Solution to Car Pollution

A researcher from the University of British Columbia has concluded that road pricing is the most effective traffic management strategy for reducing urban pollution.
Photo via Pixabay

Motor vehicles are a huge source of pollution in cities. For many years, governments have used traffic management strategies to try and reduce vehicle emissions—but few seem to have made as much of a difference as road pricing.

Road pricing is essentially a “pay per use” plan that levies charges such as road tolls, congestion charges, and charges designed to discourage the use of certain types of vehicles or fuel sources in order to reduce pollution and congestion within city limits.

University of British Columbia transportation expert and civil engineering professor Alexander Bigazzi reviewed 65 studies on traffic management strategies in Asia, Europe, and the Americas. He concluded that road pricing is the most effective strategy to reduce emissions and traffic.

Other traffic management strategies include speed enforcement programs, lane management (e.g., HOV lanes), road and congestion pricing, and trip reduction strategies such as telecommuting or ride sharing.

“The strategies with the best evidence of air quality improvements are area road/congestion pricing and low-emission zones,” Bigazzi said. “Other strategies have potential benefits, but there is less empirical evidence, either because the benefits are very small or because the benefits are offset by some other effect.”

Why are road pricing and low-emission zones so effective? A major reason is that they reduce the amount of driving. They also ease congestion and reduce emission rates. Low-emission zones also encourage people to buy cleaner vehicles.

Of course, road pricing has to be implemented on a pretty large scale in order to be effective. Cities can’t just implement road pricing on certain roads, because motorists would find other ways to get into the city where they are not faced with road pricing or low-emission zones.

“Hundreds of cities in Europe have congestion pricing or low-emission zones in their city centers and are enjoying improved traffic flow and air quality,” Bigazzi said. “These strategies haven’t been embraced in North America in the same way for a variety of reasons, but there are great potential benefits for cities here ready to embrace innovation.”

What do you think? Would you like to see cities use traffic management strategies like road pricing in order to reduce pollution, even if it meant less convenience for you? Do you think road pricing would work in your city? Please share your thoughts in the comments!

Nature, Science

The Dog Domestication Date Debate Has Been (Sort Of) Resolved

The dog domestication date debate may have been resolved, thanks to scientists from Cornell.
Photo: Shutterstock

You might not know this, but there are two distinct arguments about when dogs were domesticated. One group believes dogs were domesticated in the Paleolithic age (more than 17,000 years ago), and another believes dogs were domesticated much later, in the Neolithic age (17,000 to 7,000 years ago).

So, when exactly were dogs domesticated?

A team of researchers from Cornell University set out to find out which camp is right. They used 3-D scans of fossils to help determine the difference between wolves and dogs by studying ancient fossil canid mandibles (jaw bones) to determine if they were dogs or wolves.

How does mandible evolution distinguish a dog from a wolf? Wolves have fairly straight mandibles, while those of dogs are curved. These features become evident in 3-D scans.

The researchers, led by Abby Grace Drake, a senior lecturer in Cornell’s Department of Ecology and Evolutionary Biology, found that in the early stages of domestication, canids’ skulls changed shape, but the evolution of the mandible lagged behind.

“A lot of the fossil evidence for the date of dog domestication is based on morpohological [structural] analysis of mandibles,” said Drake, the paper’s first author. “Our study shows that when you measure modern dog mandibles and wolf mandibles using 3-D measurements you can distinguish them, and yet when we looked at these fossil mandibles, they don’t look like dogs or wolves.”

Although the team could distinguish 99.5 percent of modern dogs’ mandibles from those of wolves, a lot of the fossil mandibles couldn’t be classified as either dog or wolf. However, other data proved that the fossils were dog remains.

Other evidence from two Russian sites showed that the canid remains were found with human dwellings, and there were marks that revealed butchery—meaning that the dogs were eaten. In addition, isotope analysis of canid and human remains at both sites indicates that canids and humans both ate fish, and that humans were feeding the canids.

Drake said that since mandibles don’t appear to evolve as rapidly as the skull, they are not reliable for identifying early dog fossils.

However, 3-D analysis of canid skulls uses landmarks across the skull—differences in the angle of the muzzle, snout, and eye orbits—provides more evidence of dogs’ domestication time.

“The earliest dogs I’ve seen in my analysis were from 7,000 to 9,000 years ago,” Drake said.

Climate Change, Conservation, Nature

Old Nautical Charts Reveal Coral Loss

British navigation charts from the 1800s show us how much coral has disappeared.
British navigation charts from the 1800s show us how much coral has disappeared. Photo: Shutterstock

Nautical charts mapped in the 18th century are showing modern researchers just how much coral has been lost around the world.

A new U.S. and Australian study has compared early British navigation charts to modern coral habitat maps to determine what changes have taken place over the past three centuries.

The study was led by Professor Loren McClenachan of Colby College in Waterville, Maine, with assistance from the University of Queensland (UQ) in Australia and the Australian Research Council Centre of Excellence in Coral Reef Studies.

Professor John Pandolfi of UQ said that the study used information from “surprisingly accurate” 18th century nautical charts and satellite data to understand coral loss in the Florida Keys.

Professor McClenachan said that more than half of the coral reef habitat mapped in the 1770s was no longer there. In some areas, coral loss was close to 90 percent.

“We found near the shore, entire sections of reef are gone, but in contrast, most coral mapped further from land is still coral reef habitat today,” McClenachan said.

This is one of the first studies where marine scientists have measured the loss of coral reef habitats over a large geographic area. Most studies look more closely at the loss of living coral from smaller sections of reefs.

“We found that reef used to exist in areas that today are not even classified as reef habitat anymore,” Pandolfi said. “When you add to this the 75 percent loss of living coral in the Keys at that finer scale, the magnitude of change is much greater than anyone thought.”

Dr. Benjamin Neal of the Bigelow Laboratory for Ocean Sciences in East Boothbay, Maine, said that the early maps were remarkably precise.

“They had the best technology and they used it to create new information that conferred a lot of power,” Neal said. “The maps were essential to expansion of the British Empire, and luckily for us, they also included a lot of useful ecological information.”

This research has important conservation implications. As the authors said, when large-scale changes like this were overlooked, scientists could miss out on information about past abundance.

“We tend to focus on known areas where we can measure change. That makes sense. Why would you look for coral where you never knew it was?” McClenachan said.