Hawai`i research: Climate change with us for seven generations, or more

University of Hawai`i researchers, after studying previous climate cycles, conclude that climate change will be with us a long, long time.

And it’s because of our persistent use of carbon-based fuels, said University of Hawaiʻi at Mānoa oceanographer Richard Zeebe in a paper in the Proceedings of the National Academy of Sciences. A press releaseon the paper is here.

(Image: Earth, from space. Credit: NASA.)

That carbon use has driven the atmospheric carbon-dioxide  index from 280 to 400 parts per million since the start of the industrial age. And that in turn will drive further warming, whose impacts will include continued melting of large ice sheets and resulting sea level rise.

Zeebe looked at the feedback in the climate system caused by such warming. There are faster feedback mechanisms like snow cover and clouds (as snow and cloud cover change, the amount of solar radiation reflected away from the planet also changes.) But there are slower feedback mechanisms as well, including impacts from changing vegetation patterns. And some of those changes could extend for centuries, he calculated

“The calculations showed that man-made climate change could be more severe and take even longer than we thought before… We need to put the impact that humans have on this planet into a historic and geologic context.” Zeebe said.

“By continuing to put these huge amounts of carbon dioxide in the atmosphere, we’re gambling with climate and the outcome is still uncertain.  The legacy of our fossil fuel burning today is a hangover that could last for tens of thousands of years, if not hundreds of thousands of years to come.”

© Jan TenBruggencate 2013

Citation: Zeebe, R. E., Time-dependent climate sensitivity and the legacy of anthropogenic greenhouse gas emissions, Proceedings of the National Academy of Sciences, 110, doi:10.1073/pnas.1222843110, Aug 05, 2013.

The story about GMO-fed pigs with stomach ailments? Not exactly what they're claiming.

Lots has been made of a report that GMO feed causes stomach inflammation in pigs.

As usual, popular accounts of the science don’t tell the whole story. If you read the study, and we did, you’ll find it doesn’t say exactly what they’re saying it says.

The study, published in the Journal of Organic Systems, is entitled “A long-term toxicology study on pigs fed a combined genetically modified (GM) soy and GM maize diet.” Researcher authors are American and Australian, and include organic farming advocates, although they assert that they have no conflicts. The journal, which is Australian, is supported in part by the Organic Federation of Australia, the Australian government, and a New Zealand sustainable agriculture organization, CSAFE.

You can read the study yourself here. 

They separated 168 pigs into two equal groups, feeding some organic corn and soy, and others corn and soy that had been genetically modified for insect and/or herbicide resistance. (A few young pigs in both groups died during the 23-week trial, at rates that the authors say are standard for commercial hog production.)

The study admits that the GM-fed pigs were fed somewhat moldy feed, while the non-GM pigs received feed with less significant levels of mold. “Mycotoxin analyses (Midwest Laboratories Inc, Omaha, Nebraska, US) showed 2.08 ppb total aflatoxins and 3.0 ppm total fumonisins in a pooled sample of the GM feed and no aflatoxins and 1.2 ppm total fumonisins in a pooled sample of the non-GM feed.”

But the authors insist that this had no impact on their results: “The concentration of mycotoxins in the feed was insignificant.”

In virtually every test the researchers recount, there was no statistical difference between the two groups of pigs. They were inspected and blood was taken when they were alive, and they were autopsied once they were slaughtered.

“There were no differences between pigs fed the GM and non-GM diets for feed intake, weight gain, mortality, and routine blood biochemistry measurements,” they wrote.

The only significant difference was stomach inflammation, and even that is not nearly as clear as you’d expect, given the way the popular press has told the story.

Most of the pigs in both groups had some level of stomach inflammation, although it was not equally distributed. And in fact, 11 percent of GM-fed pigs had no stomach inflammation whatsoever, while only 5 percent of non-GM-fed pigs had no stomach inflammation at all.

Of 73 non-GM pigs, 69 had some level of stomach inflation. Of 72 GM-fed pigs, 64 had some level of stomach inflammation. The difference: in the pigs with severe inflammation of the stomachs, more tended to be GM-fed.

If you’re appalled at the presence of any stomach inflammation in pigs, know that it’s a common occurrence due to feed preparation: “The pig industry uses finely-ground feed to maximise feed efficiency which can increase inflammation and ulceration of the stomach,” the authors note.

The researchers wisely say—as researchers commonly do—that their results demand more study. What are the odds that the results would be different if you did the same study again?

But just to be clear, while their results show statistically that severe inflammation of the stomach was more common in the GM-fed pigs, it is also true that inflammation as a whole was more common in the non-GM pigs.

And it would be technically accurate, though also misleading, to write a headline that said: “Stomach inflammation in pigs higher when fed organic diet.”

© Jan TenBruggencate 2013

Hawaiian petrels forced to eat lower on food chain, industrial fishing blamed

Hawaiian petrels are eating far lower on the food chain, and a new study blames that on industrial fishing.

The takeaway from that is that the entire Pacific food web may be changing as a result of human activities. 

(Image, a Hawaiian petrel or `a`o. Credit Brenda Zaun, USFWS.)

Says the study: “Because variation in the diet of generalist predators can reflect changing availability of their prey, a foraging shift in wide-ranging Hawaiian petrel populations suggests a relatively rapid change in the composition of oceanic food webs in the Northeast Pacific.”

The petrels, known in Hawaiian as `a`o, are endangered seabirds that, like the Newell’s shearwaters, nest in mountain burrows in the Hawaiian Islands. 

An abstract of the study is here. An American Bird Conservancy news release on the study is here. 

The study is fascinating. Researchers went back through fossil bird bones dating to as far as 4,000 years ago. They looked at isotopes in the bones, and were able to make conclusions about what the birds were eating. 

“Here, we use stable carbon and nitrogen isotopes to study the foraging history of a generalist, oceanic predator, the Hawaiian petrel (Pterodroma sandwichensis), which ranges broadly in the Pacific from the equator to near the Aleutian Islands,” the authors wrote.

The research shows that up until about 100 years ago, the diet of the birds was the same for centuries. And then it changed significantly. The changes in isotopes suggest a switch from larger fish to smaller ones, from higher on the food chain to lower.

Which in turn suggests there weren’t as many bigger fish around for the petrels to eat. It’s clear that the diet change occurred. Precisely how is not so clear.

Say the authors: “The nitrogen isotope ratio declined in the petrel following the onset of large-scale industrial fishing, which could have affected the petrel diet through several mechanisms. 

"Many seabirds such as the Hawaiian Petrel forage in association with schools of large predatory fish, such as tuna and billfish that drive prey to the ocean surface. Depleted numbers of these schools, therefore, may reduce the availability of prey for the petrel. Additionally, it is possible that that petrel prey species have been depleted by direct harvest or bycatch in fisheries.”

The study is Millennial-scale isotope records from a wide-ranging predator show evidence of recent human impact to oceanic food webs, in PNAS, the Proceedings of the National Academy of Sciences. Authors include Anne E. Wiley. Peggy H. Ostrom, Andreanna J. Welch, Robert C. Fleischer, Hasand Gandhi, John R. Southon, Thomas W. Stafford, Jr., Jay F. Penniman, Darcy Hu, Fern P. Duvall, and Helen F. James.

Several of them are with Hawai`i research organizations, including Pacific Cooperative Studies Unit, University of Hawaii; National Park Service in Honolulu, and the Hawai`i Department of Land and Natural Resources.

More on Hawaiian petrels at this Fish and Wildlife Service website.

© Jan TenBruggencate 2013

Research: More carbon is flowing into the water than anyone knew

A lot of the planet’s carbon, which scientists assume is in the soil, is actually flowing into the water.

And in some ways—from a climate change perspective—that could be a good thing, according to a team of researchers that includes University of Hawai`i oceanographer Fred Mackenzie.

Okay, your eyes are going to glaze over when you read this, but a quick takeaway is this: New research is constantly improving, clarifying and tightening estimates of what’s likely to happen in our climate future.

(Image: An aerial of sediment flowing from the land into the aquatic environment. Credit: Pierre Regnier, Copyright ESA 2003)

When carbon is washed into the rivers, lakes and oceans, a lot of it can be stored there in the form of sediment. And that sediment is far less likely to release the carbon back into the atmosphere. That is because in a warming climate, soil will release carbon before underwater sediment will.

That’s one point made by Mackenzie and a large team of researchers in their paper, Anthropogenic perturbation of the carbon fluxes from land to ocean, in the journal Nature Geoscience. An abstract is available here. 

This is complex stuff, but essentially it means the models of climate change will get a little more accurate, presuming that folks developing global warming estimates adjust their assumptions, the authors say: “So far, global carbon budget estimates have implicitly assumed that the transformation and lateral transport of carbon along this aquatic continuum has remained unchanged since pre-industrial times.”

In fact, the carbon transport to aquatic bodies has not been stable. It has increased over time, the authors say. And what that means is that there’s a lot of carbon hidden in sediments that haven’t been included in global carbon calculations.

Says a press release on the study: “increased leaching of carbon from soil, mainly due to deforestation, sewage inputs and increased weathering, has resulted in less carbon being stored on land and more stored in rivers, streams, lakes, reservoirs, estuaries and coastal zones – environments that are together known as the ‘land-ocean aquatic continuum’.”

“The budget of anthropogenic CO2 reported by the Intergovernmental Panel on Climate Change (IPCC) currently does not take into account the carbon leaking from terrestrial ecosystems to rivers, estuaries and coastal regions. As a result of this leakage, the actual storage by terrestrial ecosystems is about 40% lower than the current estimates by the IPCC,” said co-author Pierre Regnier from Université Libre de Bruxelles.

An interesting note from the study: not all that much of the carbon, only about 10 percent, ends up in the oceans. 

© Jan TenBruggencate 2013

Black holes were common in early universe: UH researcher

As many as one in five of the most energetic objects of the early universe were black holes—those fascinating deep space vacuum cleaners whose gravity is so immense that even light can’t escape.

An astronomical team that included University of Hawai`i’s Guenther Hasinger reported in The Astrophysical Journal that black holes formed early and often in the young universe.

(Image: Background radiation from when the universe was only a few hundred years old can provide hints of its structure. More detail on hthis image is here. Credits: Illustration by Karen Teramura, UHIfA. Credits for inserted images: cosmic microwave background (left): NASA WMAP Science Team; black hole blow up, AGN (center, top): NASA/JPL-Caltech; first stars blow up (center, bottom): NASA/JPL-Caltech, A. Kashlinsky (GSFC); Hubble Ultra Deep Field (right): NASA/ESA, S. Beckwith(STScI) and the HUDF Team.)

Hasinger, the Director of the university’s Institute for Astronomy, was part of a team that compared background infrared and x-ray signals dating back to the early universe. They used two NASA observatories, the Chandra X-ray Observatory and Spitzer Space Telescope

"We wanted to understand the nature of the sources in this era in more detail, so I suggested examining Chandra data to explore the possibility of X-ray emission associated with the lumpy glow of the CIB (cosmic infrared background )," Hasinger said. (Hasinger in photo at right. Credit: UH/IfA)

By comparing the results of the x-ray and infrared, they were able to determine that there were fluctuations in energy that were consistent in both forms of radiation, and that there was information in those fluctuations.

"This measurement took us some five years to complete and the results came as a great surprise to us," said Nico Cappelluti, an astronomer with the National Institute of Astrophysics in Bologna, Italy, and the University of Maryland, Baltimore County, in Baltimore.

In complex calculations, the scientists removed from the data the known star and galaxy sources of energy, and were left with a remainder they could study. And since black holes are particularly intense, energetic energy sources, the astronomers believed they could identify black hole signatures in the remnant radiation maps.

"Our results indicate black holes are responsible for at least 20 percent of the cosmic infrared background, which indicates intense activity from black holes feeding on gas during the epoch of the first stars," said Alexander Kashlinsky, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

All of that leads us into a detour into the insane world of black holes.

The density of the interior of black holes is so immense that nothing gets out. But like a stealthy beast that only makes a lot of noise when it’s eating, black holes are detectable because of the big energy signature of matter being sucked into them.

Around many black holes are accretion disks, where matter is being sucked toward oblivion. And where this final sucking occurs is called the “event horizon.” The matter spinning toward the event horizon lights up and sends out a kind of final radiation distress signal before it is gone. Like a cry of help from someone being drawn into a whirlpool.

Today, there are not nearly as many black hole signatures as there were in the early universe. Hasinger said that many of the universe’s black holes have gone silent. They have sucked all the matter in their regions of space, so there’s nothing left to eat—no accretion disks, so no radiation.

“Today only about 1% of all of these black holes are actively eating and radiating, while in the early universe probably all of them were active,” Hasinger said.

Today, astronomical research indicates every galaxy has a supermassive black hole at its center, and the larger galaxies have larger supermassive black holes. Supermassive black holes have masses ranging from a million to several billion solar masses.

For more information, visit: http://www.ifa.hawaii.edu/info/press-releases/blackholes2013/

© Jan TenBruggencate 2013