Friday, October 31, 2014

Does efficiency make you use more? It's the rebound effect.

If you switch to new energy-efficient LED lights, are you less concerned about switching them off when you leave the room?

If you get a new-fuel-efficient car, do you drive more?

It’s called the Rebound Effect—the tendency to conserve less when you’ve become more efficient.

It’s real, according to a series of studies out in the past couple of years. Among those is The Rebound Effect and Energy Efficiency Policy, by Kenneth Gillingham of Yale University, David Rapson of the University of California, Davis, and Gernot Wagner of the Environmental Defense Fund.  

But the rebound effect is also complex. It can behave differently in different sectors.

The bottom line is that some folks argue that the rebound effect is a bad thing—promoting excessive use of resources.

The paper argues the opposite. To the degree that efficiency gains let you use lights, refrigeration, transportation or even air conditioning without additional costs, that rebound improves life—it’s a good thing.

“While the energy savings from energy efficiency policies will be reduced by the presence of a rebound effect, a (zero cost energy efficiency improvement)  is likely to both conserve energy and increase welfare,” the authors say.

The American Council for an Energy Efficient Economy yesterday published a paper, The ReboundEffect – Mountain or Molehill?
It estimates that the Rebound Effect can reach 20 percent, meaning that you only get 80 percent of the benefit from efficiency efforts. But AEEE argues that’s still a very good thing.

“The truth is that for 40 years energy efficiency has had a dramatic effect on worldwide energy consumption. In the United States, if we were to use energy today at the rate we were in 1974, we would be consuming more than twice the amount that we are actually using,” writes ACEEE Executive Director Steven Nadel.

© Jan TenBruggencate 2014

Sunday, October 26, 2014

Want more fish? Throw back big females.

If we were talking about humans, the acronym, BOFFFF would be a horribly inappropriate term.

But we’re talking about fish, and the term represents the most valuable and important members of the school—animals that are big, old, fat, female, fecund (or fertile) fish.

(Image: Bluefin trevally in the Northwestern Hawaiian Islands. You want to save the big ones. Credit: Dwayne Meadows, NOAA/NMFS/OPR)

And what’s important about them is that they reproduce more, have healthier and bigger eggs, have young more likely to survive, they may spawn at different times than younger fish so they increase species’ chance of success, and they are more likely to survive hard times than smaller, skinnier fish.

And what does that mean for the fishing community? They’re the ones you ought to throw back.

“Increasingly, fisheries managers are realizing that saving some big old fish is essential to ensure that fished populations are stable and sustainable,” said Mark Hixon, the University of Hawai`i researchers who was the lead author in a new paper, BOFFFFs: on the importance of conserving old-growth age structure in fishery populations.
His co-authors are Darren W. Johnson of California State Long Beach and Susan M. Sogard of the National Marine Fisheries Service. Theypublished in the ICES Journal of Marine Science.

“The loss of big fish decreases the productivity and stability of fishery stocks,” Hixon said.

The big old fat females have been shown to be important in a broad range of fish, both in fresh and salt water. They have the resources to survive periods of low food. They produce enormously more eggs than smaller fish. Their eggs are bigger and more likely to produce successful young. 

And the difference in egg production is amazing. A 27-inch ‘ōmilu or bluefin trevally, as an example, produces 84 times more eggs than a 12-inch fish. The increase with age is not the case with every fish species, but it seems to be the case with most of them.

And yet, we are removing them from the fish population faster than others. 

“Fishing differentially removes BOFFFFs, typically resulting in severe truncation of the size and age structure of the population. In the worst cases, fishing mortality acts as a powerful selective agent that inhibits reversal of size and age truncation, even if fishing intensity is later reduced,” the authors write.

Another way of saying that: If you keep taking the big, fat, females out of the population, you’re likely to end up with few fish overall, and fewer big, fat fish.

One of the solutions to this issue is slot limits—you keep the fish in the middle size slot, while releasing keiki as well as the biggest fish. But there are other ideas for fishery enhancement, as well.

“A growing body of knowledge dictates that fisheries productivity and stability would be enhanced if management conserved old-growth age structure in fished stocks, be it by limiting exploitation rates, by implementing slot limits, or by establishing marine reserves, which are now known to seed surrounding fished areas via larval dispersal,” the authors wrote.

A University of Hawai`i press release on the paper is here

© Jan TenBruggencate 2014

Monday, October 20, 2014

Big tsunami: Just 500 years ago, a 9.25 magnitude Aleutian quake blasted Hawaiian shores

A stunningly large Aleutian-sourced tsunami hit the Hawaiian Islands 4-500 years ago, requiring a much more aggressive assessment of potential shoreline damage from future waves.

Much of the preliminary evidence for the big wave comes from the Makauwahi Sinkhole on south Kaua`i, but scientists expect to find more evidence once they start looking for it on other islands.

(Image: Researchers simulated earthquakes with magnitudes between 9.0 and 9, and found that the unique geometry of the eastern Aleutians would direct the largest post-earthquake tsunami energy directly toward the Hawaiian Islands. The red circles are centered on Kaua‘i and encircle the Big Island. Credit: Rhett Butler)

And what that means is that it could happen again.

A report on the wave was published this month in the journal Geophysical Research Letters. The article, “Paleotsunami evidence on Kaua‘i and numerical modeling of a great Aleutian tsunami,” was written by Rhett Butler of the Hawai‘i Institute of Geophysics and Planetology, University of Hawai‘i at Mānoa, David Burney of the National Tropical Botanical Garden and David Walsh of the Pacific Tsunami Warning Center.

 Burney’s investigations of the sinkhole revealed a huge layered collection of marine debris that he determined could only have come from a tsunami, ripping up coral and rock from the ocean floor and depositing it over a limestone shelf into the sinkhole. 

The wave came 300 feet inland and rose more than 20 feet to dump debris into the sinkhole.

It was the massive 2011 Tohoku quake in Japan, with a magnitude of 9.0, that raised the awareness of researchers that such events were possible. They now assume at a quake that large may occur from the Aleutians every 1,000 years or so.

To account for the Makauwahi dune debris layer, they figure the quake would have needed to be even bigger than Tohoku.

“Using high-resolution bathymetry and topography we model tsunami inundation of the sinkhole caused by an earthquake with a moment magnitude of Mw ~9.25 located in the eastern Aleutians. 

“A preponderance of evidence indicates that a giant earthquake in the eastern Aleutian Islands circa 1425–1665 A.D… created the paleotsunami deposit in Kaua‘i. A tsunami deposit in the Aleutians dated circa 1530–1660 A.D. is consistent with this eastern Aleutian source region,” said the paper.

And why is this kind of study important? The authors write:

“The focus of tsunami energy from the Aleutians directed toward the State of Hawaii, and the short 4.5 (hour) tsunami propagation time, underscores the importance of tsunami readiness for Aleutian events. Hawaii State Civil Defense must make evacuation decisions 3 (hours) prior to tsunami arrival.”

© Jan TenBruggencate 2014

Sunday, October 5, 2014

Defining farming: it means what I choose it to mean

There’s a lot of discussion on Kaua`i and elsewhere about what constitutes agriculture, and whether it’s only farming if you’re growing food.

The discussion enters all kinds of arenas, from property taxation to seed research. 

If you’re growing things, but not growing food, do you still qualify for an agricultural dedication for tax purposes? Is a gentleman’s horse ranch not an agricultural enterprise unless you’re milking the mares? Should we use taxation to punish you if your crop doesn't end up in someone's belly?

If you try to define agriculture, ultimately it gets into the Alice Through the Looking Glass discussion: “It means what I choose it to mean—neither more nor less.” 

Still, there are some standards.

Breaking down the word agriculture, you get two Greek-Latin roots, meaning land and tilling. Nothing about food. (Interesting that the agri in agriculture and acre have the same Latin root—ager, for land or field.)

Breaking down the word farm, and you pass through Middle English, old German and French terms referring to both food farming and any land management that pays the rent. Ultimately in Latin there is a sense of food and feast, but also security—like something that provides you with the means for survival, or something you can use as collateral. (Farm and firm have the same Latin root, firma, meaning solid and to be relied on.)

Small farms in the American Midwest might grow corn and alfalfa to feed cattle, and they’d raise the cattle for milk and cheese, and perhaps tobacco for a cash crop, a vegetable garden, and a managed woodlot for firewood and for woodworking. As far as the farmer was concerned, it was all farming.

Trying to define agriculture too narrowly yields endless debate.

If food crops are farming, are fiber crops not? What about medicinal crops? What about energy crops (whether trees, or cane or switchgrass)?

Is raising livestock farming, and must we distinguish between a horse that pulls the plough and the cow that offers milk? If you’re raising sheep for meat, it’s farming, but if you’re raising the same sheep for wool it’s not?

And what of the cover crop that is tilled under to improve the soil? It doesn’t directly feed people, so it is not farming? But it supports the subsequent food crop, so maybe it is? Even dedicated food farmers need sometimes to grow non-food crops—cover crops, erosion control grassed areas, windbreaks—and sometimes need to leave a field fallow.

It is a slippery slope, and trying to define it too narrowly leads to trouble, as Lewis Carroll’s Alice found:

"I don't know what you mean by 'glory'," Alice said.
Humpty Dumpty smiled contemptuously. "Of course you don't—till I tell you.

This is not to say it’s impossible to make public policy of promoting food crops—just that it needs to be done very carefully.

© Jan TenBruggencate 2014

Saturday, October 4, 2014

600-year-old Polynesian voyaging canoe found on New Zealand's South Island

For Polynesian canoe culture, the New Zealand discovery of part of a 600-year-old voyaging canoe is the equivalent of finding King Tut’s tomb.

The only other comparable discovery was when Bishop Museum’s Yosi Sinoto in the late 1970s found the remains of a voyaging canoe at Fa`ahia on the French Polynesian island of Huahine. 

(Image: The carving of a turtle is visible on the hull of an ancient Polynesian voyaging canoe found on New Zealand’s South Island. (Credit: Tim Mackrell / The University of Auckland.)

And that’s it. There are virtually no other large surviving parts of Polynesian voyaging canoes.

The latest discovery was written up in Proceedings of the National Academy of Sciences by authors Dilys Johns, Geoffrey Irwin and Yun Sung, all of the University of Auckland. The title: “An early sophisticated East Polynesian voyaging canoe discovered on New Zealand’s coast.

From a single plank nearly 20 feet long, presumably from above the keel on the back half of the canoe hull, a great deal of information was extracted. 

Two of the most fascinating features: A raised relief turtle carved into the outside of the hull; And both ribs and longitudinal stringers carved into the plank, presumably for strength but in the case of the stringer, for lashing internal frameworks.

The plank was found among driftwood after a storm on the east South Island inlet of Anaweka.

“The canoe dates to approximately A.D. 1400 and was contemporary with continuing interisland voyaging. It was built in New Zealand as an early adaptation to a new environment, and a sea turtle carved on its hull makes symbolic connections with wider Polynesian culture and art,” wrote the authors.

The canoe was built of a New Zealand tree called matai (Prumniopitys taxifolia). There were holes around the perimeter of the plank for lashing. While Hawaiian canoes were generally carved of a single hull with upper parts lashed to them, many South Pacific island groups made canoes of multiple planks that were lashed together.

The plank apparently had been safely buried in the sand dune along a freshwater stream for a long time. There was still caulking material in four of the lashing holes, made of the bark of the totara (Podocarpus totara). 

The inside of the hull showed adz marks, but the outside was smoothly polished. The hull was carbon dated to as early as the middle 1200s, but that would have been the age of the tree used to make the plank, not the age of the canoe. The caulking dated to the middle 1300s to as late as 1410.

Polynesians are believed to have arrived in New Zealand around 1200. The Anaweka canoe shows that they continued to voyage and built canoes locally once they arrived. 

“The canoe is contemporary with early archaeological settlements around New Zealand and on-going voyaging between Polynesian islands,” the authors said. In recreating the entire canoe from the shape of the stern plank, the researchers assume the canoe had been in the neighborhood of 40 to 50 feet long. There were signs of repairs, indicating it had been used over an extended period of time, and fixed when it broke.

“The age, location, size and sophistication of the find all suggest that it was from a sea-going sailing canoe, but the obvious question is what type of canoe it was,” the authors wrote.

What they concluded was that it may have been a very similar vessel to the one Sinoto found at Fa`ahia. 

“Radiocarbon dates from the (Fa`ahia) site indicate occupation in the period A.D. 1050-1450, in the same time range as the Anaweka canoe,” they wrote.

“The Anaweka and Fa`ahia canoes were unlikely to have been of the same design, but it is possible that they could have come from the same design tradition. In that sense, the evidence from two widely separated locations in East Polynesia are complementary,” the authors wrote.

“The Anaweka canoe was a large, sophisticated and powerful craft…last caulked around A.D. 1400…It was active on the exposed open sea coast of the South Island,” they concluded.

© Jan TenBruggencate 2014