Tag Archives: Proceedings of the National Academy of Sciences

Fossil Fuel Emissions Messing Up Radiocarbon Dating, Making The World Appear Older

Repost from Think Progress

Fossil Fuel Emissions Are About To Throw Carbon Dating All Out Of Whack

 By Ari Phillips Jul 22, 2015 11:15am
CREDIT: flickr/Jeffrey

Those concerned with climate change spend a lot of time arguing that it’s not just an environmental problem, but also an economic, human rights, national security, and even mental health issue. Now a new study has found that greenhouse gas emissions could impact a range of unlikely fields due to their effect on radiocarbon dating, a much-heralded scientific method used to determine the age of objects containing organic material.

The study, published Monday in the Proceedings of the National Academy of Sciences, found that emissions from fossil fuels are artificially raising the carbon age of the atmosphere, which makes objects today seem much older than they are when scrutinized by a radiocarbon dater. This change in the ability to date objects could impact measurements commonly taken in a broad range of endeavors, including archaeology, forgery detection, forensics, earth science, and physiology.

For instance, the study suggests that by 2050 — just 35 years from now — new clothes could have the same radiocarbon date as something worn during the Battle of Hastings in 1066.

We already knew fossil fuel emissions were messing with our future, but now they might be messing with our future’s history. This is happening because carbon dating measures the percentage of carbon-14 versus non-radioactive carbon (C) found in an object to determine how long it has been around. Fossil fuels like coal and oil have been around for so long — millions of years — that all of their carbon-14, which has a half life of 5,730 years, is already decayed and gone. A half life is the period of time that it takes half a sample to decay.

As fossil fuel emissions mix into the atmosphere, they mix up the atmosphere’s carbon-14 balance by flooding it with non-radioactive carbon.

The carbon-14 in the atmosphere is absorbed by plants through photosynthesis, and when animals consume the plants they ingest it. So carbon-14 is found in all organic matter and has been used to figure out the age of thousands of artifacts since it first came into popular use in the 1940s and ’50s. Things that can be carbon dated include wood, bone, leather, hair, pottery, iron, ice cores and a host of other objects. The Dead Sea Scrolls, Stonehenge, and Ötzi the Iceman, a famous 5,500 year old mummy, were all carbon dated.

This is not the first time in modern history that carbon-14 levels have shifted. After a decrease in concentration that coincided with the Industrial Revolution, nuclear weapons testing caused a sharp rise in the middle of the 20th Century. Since then, observations show carbon-14 levels have been dropping, and they are now approaching a pre-industrial ratio, according to the press release for the study.

Carbon dating has suffered from artificial manipulation due to human impacts since it was discovered; not only from fossil fuel burning and nuclear detonations, but also agricultural chemicals that contaminate dating. It is known to be a form of science with a large margin of error. The issue now is just how large that error could become over a short amount of time.

As Gizmag reports, this variability has made it so that anything within 300 years of 1950 is considered modern according to radiocarbon dating protocol. However, if this study is correct, that 300-year margin of error could exceed 2,000 years by the end of the century.

“If we are adding non-radioactive carbon and that’s what’s happening with fossil fuels, we get this dilution effect,” Heather D. Graven, a physicist at the Imperial College London and author of the study, told the BBC.

Graven said that at current rates of fossil fuel emissions, increases in non-radioactive carbon could start to impact carbon dating by 2020. She also said there is still time to curtail this effect.

“If we reduce emissions rapidly we might stay around a carbon age of 100 years in the atmosphere, but if we strongly increase emissions we could get to an age of 1,000 years by 2050 and around 2,000 years by 2100,” she said. “If we reduced fossil fuel emissions, it would be good news for radiocarbon dating.”

So, add carbon dating to the list of reasons to mitigate greenhouse gas emissions.

NY Times: Study Shows Fracking Chemicals in Pennsylvania Drinking Water

Repost from the New York Times
[Editor:  The reporter admirably gives industry spokespersons plenty of space to refute the claims of this study.  But don’t quit reading there.  Farther down in the article is scientific rebuttal and further explanation: “Dr. Brantley described the geology in northern Pennsylvania as being similar to a layer cake with numerous layers that extend down thousands of feet to the Marcellus Shale. The vertical fractures are like knife cuts through the layers. They can extend deep underground, and can act like superhighways for escaped gas and liquids from drill wells to travel along, for distances greater than a mile away, she said.”  – RS]

Fracking Chemicals Detected in Pennsylvania Drinking Water

By Nicholas St. Fleur, May 4, 2015
A natural gas well in Bradford County, Pa., where a study found that three households had traces of 2-Butoxyethanol or 2BE, a compound found in Marcellus Shale drilling fluids. Credit Reuters

An analysis of drinking water sampled from three homes in Bradford County, Pa., revealed traces of a compound commonly found in Marcellus Shale drilling fluids, according to a study published on Monday.

The paper, published in the Proceedings of the National Academy of Sciences, addresses a longstanding question about potential risks to underground drinking water from the drilling technique known as hydraulic fracturing, or fracking. The authors suggested a chain of events by which the drilling chemical ended up in a homeowner’s water supply.

“This is the first case published with a complete story showing organic compounds attributed to shale gas development found in a homeowner’s well,” said Susan Brantley, one of the study’s authors and a geoscientist from Pennsylvania State University.

The industry has long maintained that because fracking occurs thousands of feet below drinking-water aquifers, the drilling chemicals that are injected to break up rocks and release the gas trapped there pose no risk. In this study, the researchers note that the contamination may have stemmed from a lack of integrity in the drill wells and not from the actual fracking process far below. The industry criticized the new study, saying that it provided no proof that the chemical came from a nearby well.

In 2012, a team of environmental scientists collected drinking water samples from the households’ outdoor spigots. An analysis showed that the water in one household contained 2-Butoxyethanol or 2BE, a common drilling chemical. The chemical, which is also commonly used in paint and cosmetics, is known to have caused tumors in rodents, though scientists have not determined if those carcinogenic properties translate to humans. The authors said the amount found, which was measured in parts per trillion, was within safety regulations and did not pose a health risk.

Dr. Brantley said her team believed that the well contaminants came from either a documented surface tank leak in 2009 or, more likely, as a result of poor drilling well integrity.

The nearby gas wells, which were established in 2009, were constructed with a protective intermediate casing of steel and cement from the surface down to almost 1,000 feet. But the wells below that depth lacked the protective casing, and were potentially at greater risk of leaking their contents into the surrounding rock layers, according to Dr. Brantley.

In April 2011 the three homeowners in Bradford County sued the drilling company, Chesapeake Energy Corporation, over reports of finding natural gas and sediment in their drinking well water. In May of that year, the Pennsylvania Department of Environmental Protection cited the oil and gas company for violating the Pennsylvania Oil and Gas Act and Clean Streams Law by letting natural gas enter the drinking wells, though the company admitted no fault. In 2012, the homeowners settled the lawsuit and the company bought the three households.

As a result of that suit, the state environmental protection agency recommended that the drilling company require that their wells extend what are known as intermediate casings beyond 1,000 feet.

Dr. Brantley described the geology in northern Pennsylvania as being similar to a layer cake with numerous layers that extend down thousands of feet to the Marcellus Shale. The vertical fractures are like knife cuts through the layers. They can extend deep underground, and can act like superhighways for escaped gas and liquids from drill wells to travel along, for distances greater than a mile away, she said.

Katie Brown, an energy consultant with Energy in Depth, an advocacy group for the Independent Petroleum Association of America, said the authors had no evidence that the small traces they found of 2BE, which is also used in many household items, came from a drilling site.

“The entire case is based around the detection of an exceedingly small amount of a compound that’s commonly used in hundreds of household products,” Ms. Brown wrote in an email. “The researchers suggest the compound is also found in a specific drilling fluid, but then tell us they have no evidence that this fluid was used at the well site.”

Garth T. Llewellyn, a hydrogeologist with Appalachia Hydrogeologic and Environmental Consulting and the lead author of the report, said that when his team sampled water wells that were farther away from the drilling sites, they did not find any of the compounds found in the three households. “When you include all of the lines of evidence, it concludes that that’s the most probable source,” he said.

Victor Heilweil, a hydrogeologist from the University of Utah who was not involved with the study but reviewed its details, said it was noteworthy for showing “the detailed geologic fabric explaining how these contaminants can move relatively long distances from the depth to the drinking well.”

An environmental scientist from Stanford University, Rob Jackson, who also reviewed the paper, said it “clearly shows an impact of oil and gas drilling on water quality.” But he emphasized that this instance was an exception.

The dates of the incident were not surprising to Scott Anderson, a senior policy analyst with the environmental advocacy group Environmental Defense Fund, who said that well integrity was generally poor around 2008 and 2009. He said that using casings of steel and cement at depths below 1,000 feet was a good idea in this region. But he also noted that the industry has strengthened its practices since then, including increased use of intermediate casings.

“Industry knows how to construct wells properly, but the fact is that they don’t always do so,” Mr. Anderson said. “My hope would be that papers like this will encourage industry and its regulators to do a better job of doing what they already know they are supposed to do.”