Julia Whitty

Julia Whitty

Environmental Correspondent

Julia is an award-winning author of fiction and nonfiction (Deep Blue Home, The Fragile Edge, A Tortoise for the Queen of Tonga), and a former documentary filmmaker. She also blogs at Deep Blue Home.

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Julia is a writer and former documentary filmmaker and the author of The Fragile Edge: Diving & Other Adventures in the South Pacific, winner of a PEN USA Literary Award, the John Burroughs Medal, the Kiriyama Prize, the Northern California Books Awards, and finalist for the Dayton Literary Peace Prize, and Deep Blue Home: An Intimate Ecology of Our Wild Ocean. Her short story collection A Tortoise for the Queen of Tonga won an O. Henry and was a finalist for the PEN Hemingway Award. She also blogs at Deep Blue Home.

The Ozone Hole: It's Still Up There, Changing Oceans, Maybe Climate

| Wed Feb. 6, 2013 6:21 AM EST

The ozone hole—the thinning of ozone in the lower stratosphere above Antarctica—has changed the way that waters in the Southern Ocean mix. And that has the potential to change how much CO2 the ocean sequesters from the atmosphere. Hence the course of global climate change. This according to a new paper in Science.

"This may sound entirely academic, but believe me, it's not," said lead author Darryn Waugh at Johns Hopkins' Krieger School of Arts and Sciences. "This matters because the southern oceans play an important role in the uptake of heat and carbon dioxide, so any changes in southern ocean circulation have the potential to change the global climate."

Map of local rates of sea level rise due to ocean heating below 4000m (colors and black numbers) for deep ocean basins. Also included is the rate from 1000-4000m warming (magenta) for the Southern Ocean (south of magenta line): via NOAA PMEL

The Southern Ocean has warmed at roughly twice the rate of the global mean ocean over the past few decades (even in its deep waters, map above), with some 40 percent of the anthropogenic carbon in the oceans entering south of 40°S. The authors write:

Southern ocean ventilation is driven primarily by the [prevailing] westerly winds, which have strengthened and shifted poleward over recent decades, primarily as a consequence of Antarctic stratospheric ozone depletion. Modeling studies suggest that this has caused changes in the ocean's overturning circulation and carbon uptake.

Thermohaline circulation (aka the "ocean conveyer") showing overturning circulation (aka deep water formation): Avsa via Wikimedia Commons

The overturning circulation, as I've written before (here and here and here), plays a big part in global climate. The places where the overturning circulation (also known as deep water formation) occur—just a few spots in the high latitudes—are being closely monitored for changes.

For the research reported in this paper, the authors used water samples collected in the Southern Ocean in the early 1990s and resampled again in the the middle and late 2000s. They measured chlorofluorocarbon-12, or CFC-12. That's the ozone-killing stuff that was first produced commercially in the 1930s for use in aerosols, refrigerants, and air conditioners, and which grew rapidly in the atmosphere until the 1990s when it was phased out by the Montreal Protocol. It's been useful to oceanographers ever since as a tracer for measuring water movements over time.

Comparing CFCs in the 1990s versus 2000s samples, the researchers were able to infer changes in how rapidly surface waters have mixed into the depths. They knew that concentrations of CFCs at the ocean surface increased in tandem with those in the atmosphere. So they were able to surmise that the higher the concentration of CFC-12 deeper in the ocean, the more recently those waters were at the surface.

What they found was younger than expected waters in the subtropics and older than expected waters further south. These findings correlate to observed intensification of surface westerly winds driven primarily by the Antarctic ozone hole. Which suggests that dwindling  ozone in the stratosphere is the primary cause of the observed changes in ocean circulation.

As stratospheric ozone recovers, the circulation may recover too. But there are other factors at work here. The authors conclude: 

As stratospheric ozone recovers over the next 40 to 60 years, the recent trend of intensifying summer westerly winds may slow or reverse. However, continued increases in greenhouse gases will likely lead to strengthened westerlies during other seasons. The integrated impact of these trends in Southern Hemisphere westerlies on the ocean's ventilation and uptake of heat and anthropogenic carbon is an open question.

 

We don't hear so much about the ozone hole as we did in the 1990s. But that doesn't mean it's going away anytime soon. The video (above) by the American Museum of Natural History animates projections for a slow recovery.

The ozone layer if CFCs hadn't been banned, progression by decade. Dark blue indicates zero ozone: Goddard Space Flight Center Visualization Studio

And this series of images (above) show projections of what might have become of global stratospheric ozone if we hadn't curbed our emissions through the Montreal Protocol. Dark blue indicates zero ozone.

The paper:

  • Darryn W. Waugh, Francois Primeau, Tim DeVries, Mark Holzer. Recent Changes in the Ventilation of the Southern Oceans. Science (2013). DOI:10.1126/science.1225411

 

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Butterflies Booking It North as Climate Warms

| Thu Jan. 31, 2013 6:21 AM EST
Giant swallowtail, normally a butterfly of the southern US, now increasingly appearing in the northeast: Thomas Bresson via Wikimedia Commons
 

Butterflies from the southern US that used to be rare in the northeast are now appearing there on a regular basis. The trend correlates to a warming climate report the authors of a paper in Nature Climate Change.

Subtropical and warm-climate butterflies—including the giant swallowtail (photo above) and the zabulon skipper (photo below)—showed the sharpest population shift to the north. As recently as the late 1980s these species were rare or absent in Massachusetts.

At the same time southern butterflies are moving north, more than 75 percent of northern species—with a range centered north of Boston—are rapidly declining in Massachusetts now. Disappearing fastest are the species that overwinter as eggs or larvae. Which suggests that changes in the winter climate (like more drought or less snow cover) may be harming nonadult butterflies.

Southern species like the zabulon skipper are replacing northern species in Massachusetts: Kenneth Dwain Harrelson via Wikimedia Commons

"For most butterfly species, climate change seems to be a stronger change-agent than habitat loss," lead author Greg Breed tells the Harvard Gazette. "Protecting habitat remains a key management strategy, and that may help some butterfly species. However for many others habitat protection will not mitigate the impacts of warming."

Breed points to the frosted elfin (photo above), a species that receives formal habitat protection from Massachusetts, and has increased 1,000 percent there since 1992. Meanwhile common summer butterflies that have no protection in Massachusetts (atlantis and aphrodite fritillaries) have declined by nearly 90 percent. From the paper:

Conservation agencies should not use our results to infer that all southern species are safe nor that all northern species are doomed to extinction. However, understanding mechanisms of population decline could improve management practices and limit potentially costly efforts that will have little influence on species conservation.

 

The frosted elfin is one of the most rapidly increasing butterfly species in Massachusetts with an estimated 1,000 percent increase since 1992: Geoff Gallice via Wikimedia Commons

What's extra cool about this research is that the data come from citizen scientists at the Massachusetts Butterfly Club. Over the last 19 years members have logged butterfly species and numbers on some 20,000 expeditions through Massachusetts. Their records fill a crucial gap in the scientific record.

Butterflies are turning out to be the canaries in the coal mine of climate warming:

  • This study in Biology Letters found that Australia's common brown butterfly emerged from their pupae on average 1.6 days earlier each decade between 1941 and 2005, when average air temperature increased by 0.14°C per decade.
  • Butterflies and other species living in the mountains suffer from the "escalator effect"... i.e., when there's no higher "latitude" for them to shift to beyond the summit.
  • MoJo's Kiera Butler wrote here about the Karner blue butterfly and the problem of what to do when conditions force them northward but they can't make it past urban roadblocks.
  • I reported here about populations of Apollo butterflies in the Rocky Mountains so fragmented by the escalator effect that they could be wiped out by one particularly bad weather event.
  • Check out this Google Scholar search page for just how many papers are being published on butterflies feeling the heat.

The Nature Climate Change paper:

  • Greg A. Breed, Sharon Stichter & Elizabeth E. Crone. Climate-driven changes in northeastern US butterfly communities. Nature Climate Change (2013). DOI:10.1038/nclimate1663

With Warming, Soil Releases More CO2... Though Less Over Time as Microbes Adapt

| Sun Jan. 20, 2013 1:06 PM EST
Study plots at the Harvard Forest Long-Term Ecological Research site in Massachusetts where researchers have been warming two areas with underground cables to simulate a warmer climate. The photo shows a January thaw on a 50°F day. The heated plots melted before the unheated ones: Alix Contosa, postdoctoral researcher at University of New Hampshire

Warmer temperatures from a warming climate force the release of carbon dioxide from soils into the atmosphere, driving even more climate warming. That's the bad news. The good news is that the effect diminishes over time—over 18 years, and counting. This according to a new paper just published in Nature Climate Change.

We know that microorganisms in the soil release 10 times the CO2 that humans release on a yearly basis. These soil processes are normally kept in check by plants, which uptake C02 from the atmosphere. But a warming climate is driving changes in the carbon cycle.  

Model soil bacteria: pmecologic via Flickr

To examine how that might be unfolding on at least one patch of our planet—the Harvard Forest Long-Term Ecological Research site in Massachusetts—the researchers warmed two plots with underground cables, one plot for two years, the other for 18. They then measured the efficiency of soil organisms in utilizing food sources that come from plants. Here's some of what they found:

"When the soil was heated to simulate climate warming, we saw a change in the [soil] community to be more efficient in the longer term," says Frey.
  • In the two-year scenario, warming temperatures drastically reduced the efficiency of soils to utilize complex food sources (specifically phenol) from decomposing wood and leaves by 60 percent.
  • In the long-term scenario, where soils were warmed to 9°F (5°C) above ambient temperatures for 18 years, the soil microorganisms regained some efficiency—suggesting that warmed soils might eventually release less CO2 than otherwise predicted.

Why the change? The authors hypothesize that long-term warming may change the community of soil microorganisms to become more efficient. Perhaps the composition of the species changes, or the original species adapt, or the availability of various nutrients changes, or some or all of the above.

"While they're low on the charisma scale soil," says lead author Serita Frey, at the University of New Hampshire, "[soil] microorganisms are so critically important to the carbon balance of the atmosphere."

(Thanks microorganisms!)

These findings could lead to critical changes in the way the carbon cycle is predicted, since common ecosystem models don't factor in the temperature response of the microbial community. "There is clearly a need for new models that incorporate an efficiency parameter that is allowed to fluctuate in response to temperature and other environmental variables," says co-author Johan Six, at the University of California, Davis.

In the video, author Serita Frey describes her long-term work with soil.

The paper:

  • Serita D. Frey, Juhwan Lee, Jerry M. Melillo, and Johan Six. The temperature response of soil microbial efficiency and its feedback to climate. Nature Climate Change. DOI: 10.1038/NCLIMATE1796

TSA Dumps Porno Airport Scanners. Good Riddance!

| Fri Jan. 18, 2013 4:37 PM EST

 

Image from a backscatter X-ray airport scanner, of the kind that will be gone from all US airports by June: US Dept of Homeland Security via Wikimedia Commons

By June those X-ray-emitting, full-frontal-and-full-backside-exposing airport scanners will be gone, the Transportation Security Administration announced today. The reason: Rapiscan, their maker, can't meet the software requirements to block the naked view of travelers for a more generic one.

David Kravets at Wired Blog writes of another potential (and potentially more ominous) reason for the ban—falsifying test data:

The announcement comes three months after Rapiscan came under suspicion for possibly manipulating tests on the privacy software designed to prevent the machines from producing graphic body images.

The European Union has already banned backscatter X-ray scanners over health concerns... worries that most X-rays are received by one of our more supersensitive organs: our skin. I wrote about that here and here.

TSA removed 76 of the X-ray scanners from busier airports last year and will dump the remaining 174 by June, reports Bloomberg. Although all those porno scanners are destined for government agencies across the country. Sorry, federal employees. 

Meanwhile in US airports TSA will continue to deploy the (presumably safer) millimeter wave technology scanners made by L-3 Communications, which has mastered generic-outline imaging. 

Personally, I'm just glad I won't have to get to the airport extra early anymore to make the extra long wait for an extra special pat down.

Plastics Suck Up Other Toxins: Double Whammy for Marine Life, Gross for Seafood

| Fri Jan. 18, 2013 6:21 AM EST

Photo courtesy of Kent K. Barnes / kentkb

Some plastics are worse than others for the marine life that accidentally or intentionally eat them. That's because not only are the plastics themselves toxic but some also act as sponges for other toxins. Unfortunately the most commonly produced plastics also absorb the most chemicals. This according to a new study in early view in Environmental Science & Technology

"It surprised us that even after a year some plastics would continue to take up contaminants."

The researchers measured the absorption of persistent organic pollutants (POPs)—specifically polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs)—to the five most common types of mass-produced plastics:

  • Polyethylene terephthalate (PET). Recycling symbol #1. Example: Water bottles.
  • High-density polyethylene (HDPE). Recycling symbol #2. Example: Detergent bottles. 
  • Polyvinyl chloride (PVC). Recycling symbol #3. Example: Clear food packaging
  • Low-density polyethylene (LDPE). Recycling symbol #4. Example: Plastic shopping bags
  • Polypropylene (PP). Recycling symbol #5. Example: Yogurt containers, bottle caps.

From this research it seems that stuff made from polyethylene and polypropylene likely poses a greater risk to marine animals (and presumably the people that eat them) than products made from PET and PVC. Though the authors note that PVC is carcinogenic and toxic all by itself.

Laysan albatross carcass filled with ingested plastic debris, Midway Island. Nearly all carcasses found here have marine debris in them. It's estimated that albatross feed their chicks ~10,000 lbs of marine debris annually on Midway. Andy Collins, NOAA Office of National Marine Sanctuaries

The authors were also surprised to find how long the plastics kept absorbing the contaminants. At one site they estimated it would take 44 months for high-density polyethylene to stop absorbing POPs.

"As the plastic continues to degrade, it's potentially getting more and more hazardous to organisms as they absorb more and more contaminants," says lead author Chelsea Rochman (UC Davis). 

The research was conducted over a year at five sites in San Diego Bay with pellets of each type of plastic immersed in seawater and retrieved periodically for absorption measurements. 

The paper:

  • Chelsea M. Rochman, Eunha Hoh, Brian T. Hentschel, and Shawn Kaye. Long-Term Field Measurement of Sorption of Organic Contaminants to Five Types of Plastic Pellets: Implications for Plastic Marine Debris. Environmental Science & Technology (2013). 
 
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