Environmental pollutants - could they be causing weight gain?

There's been quite a lot of research in recent years on the impact of various pollutants on weight gain. About four years ago, a Spanish study linked exposure to hexachlorobenzene (HCB) in the umblicial cords of newborns, and found that those who'd been exposed in the womb were more likely to be overwieght at six. (This chemical is mainly used to treat seeds, so it had implications for those living in and around agricultural areas.)
Now there's new evidence that perfluorooctanoic acid (PFOA) may also be linked to weight gain. PFOA is ubiquitous - it's found even in the middle of the Pacific Ocean and all the inhabited continents, and is now found in animals, poor sods. It's been made since 1951, and was used in non-stick surfaces (they say it's not anymore), outdoor clothing, treatments for carpets and tiles and more.

Environmental pollutant linked with overweight

The levels of the environmental pollutant perfluorooctanoic acid (PFOA) that mothers had in their blood during pregnancy increased the risk of obesity in their daughters at 20 years of age. The findings come from a recent study of Danish women in which the Norwegian Institute of Public Health participated.

In recent decades, there has been a sharp increase in the number of overweight children and adults worldwide. It is suspected that diet and exercise alone cannot explain this large weight increase.

Researchers suggest that the increasing levels of endocrine disrupters in the environment may be a possible contributing factor. Therefore, this study was established and discovered the following:

Daughters of mothers with the highest concentrations of PFOA in the blood during pregnancy were three times as likely to be overweight at the age of about 20 years as daughters of mothers with the lowest PFOA levels.
The calculations took into account many variables, such as maternal weight and lifestyle factors.
An association was also found between PFOA exposure before birth and elevated levels of insulin and leptin, two hormones that are linked to obesity.
Levels of insulin and leptin were also elevated in the sons of mothers with high PFOA, but the relationship was weaker than for girls.
There was no increased risk of development of obesity among the sons.

What does this mean for us?

It is still too early to say what this might mean for us. The study indicates that factors such as environmental pollutants, in addition to diet and physical activity, play a role in the obesity epidemic seen today although this remains to be confirmed by similar studies.
EurekAlert, 22 February 2012

Summer temperatures and food security

Summer temperatures will rise (or rise and fall) to a point where you can't grow certain crops. And the losers are? Wait, I have the envelope right here: "the biggest impacts will be on Europe, Africa and South America.

Models underestimate future temperature variability; Food security at risk

Climate warming caused by greenhouse gases is very likely to increase the variability of summertime temperatures around the world by the end of this century, a University of Washington climate scientist said Friday. The findings have major implications for food production.

Current climate models do not adequately reflect feedbacks from the relationship between the atmosphere and soil, which causes them to underestimate the increase of variability in summertime temperatures, said David Battisti, a UW professor of atmospheric sciences.

While warmer temperatures already have implications for food production in the tropics, the new findings suggest the increase in the volatility of summertime temperatures will have serious effects in grain-growing regions of Europe and North and South America, Battisti said.

"If there's greater variability, the odds of the temperature being so high that you can't grow a crop are greater," he said.

"In terms of regional and global food security, it's not good news."

[...]

Earlier research has shown that by the end of this century, the increase in average growing season temperature, if other factors remain the same, will likely reduce yields of rice, corn and soybean 30 to 40 percent. Already rice yields in the tropics are being affected by higher temperatures, affecting nations such as Indonesia, which frequently imports rice to stabilize prices, Battisti said.

In addition, the scientists say global warming will have greater impacts than previously thought on the El Niño Southern Oscillation, a tropical phenomenon that has global impact on climate and food production. Their conclusions are based on geological and other proxy records of climate and El Niño from the last 10,000 years, plus recent analyses of long-term climate changes because of global warming.

The Intergovernmental Panel on Climate Change, the United Nations body conducting ongoing assessments of climate change, has estimated that future month-to-month temperature variability during summer months is likely to be greater in some places and less in some places, but should stay roughly constant in many places.

But the new modeling work, Battisti said, shows most areas can expect to see greater variability in summer temperatures between now and 2085, with the biggest impacts in Europe, Africa and South America.

"The increased variability will be pretty ubiquitous. You will see it pretty much everywhere."

Increased temperature variability compounds the loss of production because of higher average temperatures, Battisti said. Add higher fertilizer prices and other market pressures to the mix "and food insecurity is likely to be higher than it has been for some time."
(EurekAlert 17 Feb 2012)

Stormy weather

Did you know that the South-West Indian Ocean cyclone basin is one of the deadliest in the world, with about 80 people dying a year? The season begins in mid-November and ends around end April - although it can linger for a month more around Mauritius and Reunion. Apparently it averages about 10 storms a year. There's a new one brewing, and NASA caught footage of it. It's expectd to make landfall in Madagascar on 13 Feburary. I wonder if this cyclone basin is becoming more active? http://www.eurekalert.org/multimedia/pub/40637.php?from=204616

Thalassa, oh thalassa!

Unprecedented, man-made trends in ocean's acidity


Oh, the sea! Though not unexpected, this is such awful news:

Nearly one-third of CO2 emissions due to human activities enters the world's oceans. By reacting with seawater, CO2 increases the water's acidity, which may significantly reduce the calcification rate of such marine organisms as corals and mollusks. The extent to which human activities have raised the surface level of acidity, however, has been difficult to detect on regional scales because it varies naturally from one season and one year to the next, and between regions, and direct observations go back only 30 years.

Combining computer modeling with observations, an international team of scientists concluded that anthropogenic CO2 emissions over the last 100 to 200 years have already raised ocean acidity far beyond the range of natural variations. The study is published in the January 22 online issue of Nature Climate Change.
EurekAlert, 22 January 2012

Our oldest friend

Dog skull dates back 33,000 years

An ancient dog skull, preserved in a cave in the Altai Mountains of Siberia for 33,000 years, presents some of the oldest known evidence of dog domestication and, together with equally ancient dog remains from a cave in Belgium, indicates that domestication of dogs may have occurred repeatedly in different geographic locations rather than with a single domestication event.

In other words, man's best friends may have originated from more than one ancient ancestor, contrary to what some DNA evidence previously has indicated.

"Both the Belgian find and the Siberian find are domesticated species based on morphological characteristics," said Greg Hodgins, a researcher at the University of Arizona's Accelerator Mass Spectrometry Laboratory and co-author of the study that reports the find.

"Essentially, wolves have long thin snouts and their teeth are not crowded, and domestication results in this shortening of the snout and widening of the jaws and crowding of the teeth."


The Altai Mountain skull is extraordinarily well preserved, said Hodgins, enabling scientists to make multiple measurements of the skull, teeth and mandibles that might not be possible on less well-preserved remains. "The argument that it is domesticated is pretty solid," said Hodgins. "What's interesting is that it doesn't appear to be an ancestor of modern dogs." [...]

At 33,000 years old, the Siberian skull predates a period known as the Last Glacial Maximum, or LGM, which occurred between about 26,000 and 19,000 years ago when the ice sheets of Earth's last ice age reached their greatest extent and severely disrupted the living patterns of humans and animals alive during that time. Neither the Belgian nor the Siberian domesticated lineages appear to have survived the LGM.

However, the two skulls indicate that the domestication of dogs by humans occurred repeatedly throughout early human history at different geographical locations, which could mean that modern dogs have multiple ancestors rather than a single common ancestor.

"In terms of human history, before the last glacial maximum people were living with wolves or canid species in widely separated geographical areas of Euro-Asia, and had been living with them long enough that they were actually changing evolutionarily," said Hodgins. "And then climate change happened, human habitation patterns changed and those relationships with those particular lineages of animals apparently didn't survive."

"The interesting thing is that typically we think of domestication as being cows, sheep and goats, things that produce food through meat or secondary agricultural products such as milk, cheese and wool and things like that," said Hodgins.

"Those are different relationships than humans may have with dogs. The dogs are not necessarily providing products or meat. They are probably providing protection, companionship and perhaps helping on the hunt. And it's really interesting that this appears to have happened first out of all human relationships with animals."
(From EurekAlert, 24 January 2012)

Over the peak: the limits of fossil fuel

Caption: Trips to the Kruger National Park are getting more expensive!

Sometime back in 2008, I think, I wrote about the shocking things that had happened to oil prices - they'd leapt from a 'norm' of $35-40 a barrel a couple of years earlier to a new norm of around $70-80. Now the new norm seems to be around $100. All just as predicted by peak-oil experts. Here's some new corroborating evidence:

Commentary in Nature: Can economy bear what oil prices have in store?

Stop wrangling over global warming and instead reduce fossil-fuel use for the sake of the global economy.

That's the message from two scientists, one from the University of Washington and one from the University of Oxford in the United Kingdom, who say in the current issue of the journal Nature (Jan. 26) that the economic pain of a flattening oil supply will trump the environment as a reason to curb the use of fossil fuels.

"Given our fossil-fuel dependent economies, this is more urgent and has a shorter time frame than global climate change," says James W. Murray, UW professor of oceanography, who wrote the Nature commentary with David King, director of Oxford's Smith School of Enterprise and the Environment.

The "tipping point" for oil supply appears to have occurred around 2005, says Murray, who compared world crude oil production with world prices going back to 1998. Before 2005, supply of regular crude oil was elastic and increased in response to price increases. Since then, production appears to have hit a wall at 75 million barrels per day in spite of price increases of 15 percent each year.

"As a result, prices swing wildly in response to small changes in demand," the co-authors wrote. "Others have remarked on this step change in the economies of oil around the year 2005, but the point needs to be lodged more firmly in the minds of policy makers."

For those who argue that oil reserves have been increasing, that more crude oil will be available in the future, the co-authors wrote: "The true volume of global proved reserves is clouded by secrecy; forecasts by state oil companies are not audited and appear to be exaggerated. More importantly, reserves often take 6 - 10 years to drill and develop before they become part of the supply, by which time older fields have become depleted." Production at oil fields around the world is declining between 4.5 percent and 6.7 percent per year, they wrote.

"For the economy, it's production that matters, not how much oil might be in the ground," Murray says. In the U.S., for example, production as a percentage of total reserves went from 9 percent to 6 percent in the last 30 years.

"We've already gotten the easy oil, the oil that can be produced cheaply," he says. "It used to be we'd drill a well and the oil would flow out, now we have to go through all these complicated and expensive procedures to produce the oil."

The same is true of alternative sources such as tar sands or "fracking" for shale gas, Murray says, where supplies may be exaggerated and production is expensive. Take the promise of shale gas and oil: A New York Times investigative piece last June reported that "the gas may not be as easy and cheap to extract from shale formations deep underground as the companies are saying, according to hundreds of industry e-mails and internal documents and an analysis of data from thousands of wells."

Production at shale gas wells can drop 60 to 90 percent in the first year of operation, according to a world expert on shale gas who was one of the sources for the commentary piece. Murray and King built their commentary using data and information from more than 15 international and U.S. government reports, peer-reviewed journal articles, reports from groups such as the National Research Council and Brookings Institution and association findings.

Stagnant oil supplies and volatile prices take a toll on the world economy. Of the 11 recessions in the U.S. since World War II, ten were preceded by a spike in oil prices, the commentary noted.

"Historically, there has been a tight link between oil production and global economic growth," the co-authors wrote. "If oil production can't grow, the implication is that the economy can't grow either."

Calculations from the International Monetary Fund, for example, say that to achieve a 4 percent growth in the global economy in the next five years, oil production must increase about 3 percent a year.

"Yet to achieve that will require either an heroic increase in oil production, ... increased efficiency of oil use, more energy-efficient growth or rapid substitution of other fuel sources," according to the commentary. "Economists and politicians continually debate policies that will lead to a return to economic growth. But because they have failed to recognize that the high price of energy is a central problem, they haven't identified the necessary solutions: weaning society off fossil fuel."

The commentary concludes: "This will be a decades-long transformation and we need to start immediately. Emphasizing the short-term economic imperative from oil prices must be enough to push governments into action now."

Cyclone Funso

Here's the beast that caused all the trouble in Hoedspruit and the Lowveld of South Africa. NASA published a stunning satellite image here: http://www.eurekalert.org/multimedia/pub/40179.php?from=203461.