Archive for the 'General Science' Category

Oct 28 2019

The Golden Rice Saga

Published by under General Science

Science Writer Ed Regis has recently published a book, Golden Rice: The Imperiled Birth of a GMO Superfood, in which he tells the tragic story of golden rice. In his telling he does not come off as an ideologue, or someone who kept with an initial dramatic narrative regardless of the facts. Rather, he wished to find the truth, which is often messy and nuanced.

Golden rice is a genetically modified form of rice that is enriched with beta carotene, the precursor to vitamin A. It was developed by a non-profit humanitarian collaborative, is free of patents, and was produced with the intention of making it freely available to farmers in developing worlds. The first version of golden rice was produced in 2002, but this version had very low beta carotene levels. The latest versions, however, have sufficient levels that if current diets containing rice as the staple source of calories were switched to golden rice, it would be enough to avoid vitamin A deficiency.

Vitamin A deficiency is a global pandemic. According to the WHO:

An estimated 250 000 to 500 000 vitamin A-deficient children become blind every year, half of them dying within 12 months of losing their sight.

Golden rice has the potential to significantly reduce this disease burden by fortifying a daily staple with beta carotene. This sounds like a solid win for science, so what turns this into a tragic tale? Of course you know the answer, irrational resistance based on misplaced fears.

Greenpeace has lead the charge against the development and adoption of golden rice, mainly out of their generic resistance to all things GMO. Regis writes:

Over the years since the prototype version was announced, Greenpeace had issued a practically endless stream of press releases, position papers, and miscellaneous other statements about Golden Rice that were filled with factual inaccuracies, distortions, and wild exaggerations of the truth.

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Oct 24 2019

Another Damning Organic Study

Published by under General Science

A recent study looks at the carbon emission impact if England and Wales switched entirely over to organic farming. They found:

We predict major shortfalls in production of most agricultural products against a conventional baseline. Direct GHG emissions are reduced with organic farming, but when increased overseas land use to compensate for shortfalls in domestic supply are factored in, net emissions are greater. Enhanced soil carbon sequestration could offset only a small part of the higher overseas emissions.

In their model organic farming did not use fossil-fuel based fertilizer. The nitrogen comes from natural sources, like manure, and also rotation crops that fix nitrogen, such as legumes. This does result in a direct reduction in green-house gas (GHG) emissions, but also results in about a 40% decrease in crop production. That shortfall would have to be made up with increased imports, mostly from Europe. So then we have to calculate what it would take to replace the shortfall in production. This is where there is some variability in the model, because it depends exactly what land is converted to crop production. In the most likely scenarios there would be a net increase in GHG emissions of about 20%.

This is a great example of the law of unintended consequences. When dealing with any complex network, like agriculture, you have to consider the effects of any one change on the overall system. This is not the first study to show that organic farming is a net negative for the environment, and so it is in line with previous research. Further, the disadvantages of organic farming get worse as you try to scale it up.

For example, consider the nitrogen cycle – agriculture is largely a system of recycling nitrogen into food. So for any system you have to consider where all the nitrogen is coming from. Organic farming uses manure, but when the world’s agriculture was limited to manure as a source of nitrogen, that severely limited food production. The green revolution was largely created by the ability to make artificial fertilizer and therefore a non-manure based source of nitrogen. Bottom line – we cannot support the world’s population on manure.

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Oct 15 2019

Impossible Bug Burger

Published by under General Science

The market is innovating some burger alternatives in order to reduce demand for beef.  There are potentially three reasons to reduce beef consumption – health, environmental, and ethical. How successful are these replacements?

First let me quickly review the reasons for reducing beef. The health effects of eating red and processed meat are, at present, controversial. I reviewed this question recently at SBM. There is evidence for increased cancer and heart disease from eating large amounts of red and especially processed meat, but the absolute risk is low and the quality of the evidence is low. You can make of this what you will, and that’s the controversy. My take is that if you keep your total calories where they should be for weight maintenance, and eat plenty of fruits and vegetables, the rest takes care of itself.

The ethical concerns are complex and reflect personal values. Again, personally, I don’t have a problem with eating animals after they are dead, as long as they were treated humanely while they were alive and they were slaughtered in a humane way. However, I understand the points on the other side and respect the views of those who wish to avoid meat for ethical reasons. I currently file that away as a personal choice. I don’t think there is ethical justification for outlawing meat, however.

The environmental concerns are also complex, but it is clear that producing a lot of meat is very inefficient. Potatoes, for example, produce 17 times the amount of calories per acre than beef. But some land is better suited for grazing than farming. Cows also produce a lot of methane. Water usage from animals is also high. This does not mean the best thing to do is eliminate meat completely. Rather, as one study indicates, we should use land optimally. Some land is best for growing a certain kind of crop, while another might be best for grazing, while still other land is best left untouched for natural ecosystems.

Whether or not you think we should reduce meat consumption to zero or not, the evidence does suggest that industrialized nations are eating too much meat. So it is reasonable to moderate our meat consumption at the very least.

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Oct 10 2019

Ancient Food Storage

Published by under General Science

There are many things we take for granted in modern life, skills that humanity developed over literally hundreds of thousands of years, but also many modern conveniences that are fairly recent. One is food storage – saving food for later consumption.

We began as hunter-gatherers, a lifestyle that involves mostly consuming food right as it is acquired. This creates times of feast and famine, but little consistency or predictability. Without refrigeration and other techniques of food preservation, most foods would not last long. Cooked meat, gathered fruits might last a few days, while nuts and roots might last a bit longer. But that was about it.

Agriculture led to a significant increase in our control over our food supply. We could now store food as dried grains for months. As we cultivated crops, some were selected for storing well. Some hard-skinned squash, for example, can keep for several months. Cheese was a huge discovery, preserving milk calories also for months. Domesticated animals could be “preserved” indefinitely, and then slaughtered when needed. Salting, pickling, smoking, and curing were discovered over time as methods of preserving various foods. Industrialization eventually allowed for things like canning and, of course, refrigeration.

But what was the oldest and first example of humans preserving food for later consumption? Archaeologists think they have discovered it – researchers from Tel Aviv report the finding from Qesem Cave, a paleolithic human settlement from 400,000 years ago. They found evidence that the people living there would preserve deer and other bones for potentially up to 9 weeks, and then break them open to eat the marrow.

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Sep 24 2019

Climate Change Is Accelerating

Published by under General Science

Have you ever traveled with a large group of friends? When a group gets beyond a certain “critical mass” it becomes geometrically more difficult to make decisions. Even going to a restaurant or a movie become laborious. Decision making seems to break down in large groups, especially if there isn’t an established hierarchy or process in place. That’s why the “by committee” cliche exists – group decision making can be a highly flawed and problematic process.

I can’t escape the nagging sensation that the world is having this problem. We seem to be politically frozen and unable to take decisive timely action. We are metaphorically driving toward a cliff, and we can’t even take our foot off the accelerator, let alone apply the brakes.

I am talking, of course, about climate change. The World Meteorological Organization (WMO) compiled data in preparation for a UN summit on climate change in New York (which the US will not, ironically, be attending). They found:

  • 2014-2019 are the hottest 5 years on record
  • Global temperature have risen by 1.1 C since 1850, but  0.2 C between 2011-2015.
  • CO2 release between 2014-2019 was 20% higher than the previous 5 years
  • Sea level rise has been 3.2 mm per year on average since 1993, but is 5mm per year averaged over the last five years.
  • Ice loss is accelerating. For example – “The amount of ice lost annually from the Antarctic ice sheet increased at least six-fold, from 40 Gt per year in 1979-1990 to 252 Gt per year in 2009-2017.”
  • Heatwaves, wild fires, and extreme weather events are increasing and causing increasing damage and costs.

There is a decisive scientific consensus that these facts are basically accurate, that human activity is causing warming, and that the results are not going to be good. There is a growing consensus among economists that the costs of global warming will be huge, in the billions for the US alone. Even if there is still a little uncertainty, there is enough data and enough consensus to act. So what’s holding us back?

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Aug 09 2019

Some Climate Change Cherry Picking

Published by under General Science

There is an industry of misinformation fueling climate change denial. It is often fairly sophisticated, and because it is dealing with a highly complex technical area, it’s easy to create an argument that sounds compelling. This results (as if often evidenced right here in the comments) in people who are confident that they are good skeptics and climate fearmongering is all nonsense. Of course they have to simultaneously believe in a rather absurd conspiracy theory regarding the scientific community, but they make that work somehow too.

Here are a couple of recent examples, both of which involve some subtle cherry picking. The first has to do with electric cars, which are frequently opposed by the denialists, in that they oppose subsidies to help bootstrap the market. This involves the “solution aversion” aspect of climate change denial – deniers are really motivated by the proposed solutions to climate change, which goes against either their politics or other interests. The claim that is often made is that producing electric cars has a higher carbon footprint than gasoline cars, and that if you are charging your car off the grid you are probably getting that electricity from fossil fuels. Therefore – electric cars are worse for the environment.

At the very least, I see climate change deniers delight in how stupid this makes the climate change believers appear.  This is a great example of cherry picking, because the two basic facts are correct but they are not the whole picture. Here, for example, is an article posted by Breitbart claiming that batteries are not green, concluding:

One of the authors, Mats-Ola Larsson at IVL, has made a calculation of how long you have to drive a petrol or diesel before it has released as much carbon dioxide as battery manufacturing has caused.

“The result was 2.7 years for a battery of the same size as the Nissan Leaf and 8.2 years for a battery of the Tesla-size.”

Truly the enduring mystery of why Tesla is now more highly valued than such non-Potemkin U.S. car manufacturers as Ford and General Motors grows more mysterious by the hour.

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Aug 01 2019

GMOs and the Knowledge Deficit Model

A 2015 Pew survey found that 88% of AAAS scientists believe that GMOs (genetically modified organisms) are generally safe to eat, while only 37% of the general public did. This was the biggest gap, 51%, of any science attitude they surveyed – greater than evolution or climate change. This hasn’t changed much since. A 2018 Pew survey found that 49% of US adults think that GMOs are worse for your health. These numbers are also similar in other countries.

An important underlying question for science communicators is – what is the source and therefore potential solution to this disconnect between experts and the public? In other words – what drives anti-scientific or pseudoscientific attitudes in the public? The classic answer is the knowledge deficit model, that people reject science because they don’t understand it. If true, then the answer is science education and fostering greater scientific literacy.

However, psychological research over the last two decades has called into question the knowledge deficit model. Studies have found that giving facts often has not result, or may even create a backfire effect (although to scope of this is still controversial). Some research suggests you have to confront a person’s explanatory narrative and replace it with another. Others indicate that ideological beliefs are remarkably resistant to alteration with facts alone.

But the knowledge deficit model is not dead yet. It seems that we have to take a more nuanced approach to unscientific beliefs in the public. This is a heterogeneous phenomenon, with multiple causes and therefore multiple potential solutions. For each topic we need to understand what is driving that particular belief, and then tailor an approach to it.

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Jul 25 2019

The Global Warming Consensus

Published by under General Science

The degree to which there is a scientific consensus in anthropogenic global warming (AGW) remains politically controversial, even though it is not scientifically controversial. Denial of the consensus remains a cornerstone of AGW denial, so let’s examine the science and the arguments used to deny it.

Much of the public discussion focusses on the 2013 Cook article which claimed that there is a 97% consensus among experts in AGW. This has become the poster child of the consensus argument, much in the way Mann’s original article has become the icon of the “hockey stick” of global temperatures. The denialist strategy here is the same – falsely present the situation as if all the scientific eggs are in one basket, and then attack that basket with everything you have.

So Cook has been vilified by the deniers as if that demolishes the evidence for a consensus. That strategy ignores, however, the many other studies that also look at the question of consensus. In fact, there is a consensus of studies on consensus. A 2016 review of 6 independent studies found the range of estimates of the consensus is from 90-100%, with the consensus clustering around 97%. The “everything depends on that one Cook study” strategy is just factually incorrect.

The other strategy used to deny the consensus is to misrepresent individual studies, again with the focus being on Cook. There is admittedly a lot of complexity here, and no one number will capture that. No individual study is perfect, because you always have to make some trade-offs. These papers are all estimates of the consensus, and had to make certain assumptions. But that is why multiple independent estimates are useful.

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Jul 15 2019

Clouds and Climate Change

A paper is making the rounds on climate denial sites that claims to debunk human-caused climate change in a single stroke. Predictably, the paper does nothing of the sort, but it does raise a complex issue regarding climate change that is worth reviewing. But first let’s get to the paper itself.

The paper, by J. Kauppinen and P. Malmi, is a pre-publication paper on the Arxiv. This means it is not peer-reviewed. Their central claim, from the abstract:

In this paper we will prove that GCM-models used in IPCC report AR5 fail to calculate the influences of the low cloud cover changes on the global temperature.

Right in the first sentence is a huge red flag – claiming to be able to “prove” that the IPCC report is false. That’s a bold claim, and suggests a less than rigorous intellectual approach. They also claim to rebuke a rather robust conclusion built on many lines of evidence with a single line of evidence – the single stroke approach. This is also a huge red flag.

The claim is built around one major line of reasoning, that if you compare low cloud cover with changes in global temperatures, you see a strong correlation. In fact, the authors argue, you can explain most of global warming as resulting from a decrease in low cloud cover, leaving almost nothing left for anthropogenic forcing. There is a great deal wrong with this claim. The site ClimateFeedback has helpfully curated much of the response from climate scientists, who eviscerate the Kauppinen paper, and I will give you a summary of their summary.

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Jun 28 2019

Mold In Space

Published by under General Science

There are bacteria and mold aboard the International Space Station (ISS). This should come as no surprise, as these organisms follow humans everywhere we go. In fact it’s claimed that the ISS astronauts spend several hours per week cleaning mold off the ISS and wiping everything down. However, this first hand report by ISS astronaut Clayton C. Anderson says he did his cleaning duty every Saturday, but not as thoroughly as requested.

Still, as we spread into space, we need to carefully consider the microscopic ecosystem we will bring with us. A space ship or station is a self-contained environment, and as we plan trips back to the Moon and on to Mars, there will be longer and longer missions. Something as simple as a fungus may threaten those missions. A recent study of the resilience of mold spores highlights how challenging this may be.

The study looked at the effects of ionizing radiation on mold. They looked at the two most common species of mold aboard the ISS,  Aspergillus and Pennicillium. They found:

The spores survived exposure to X-rays up to 1000 gray, exposure to heavy ions at 500 gray and exposure to ultraviolet light up to 3000 joules per meter squared. Gray is a measure of absorbed dose of ionizing radiation, or joules of radiation energy per kilogram of tissue. Five gray is enough to kill a person. Half a gray is the threshold for radiation sickness.

Those are some hardy fungi. For context a one-way trip to Mars is expected to expose travelers to 0.7 gray. That will be a problem for the humans aboard, not so much the molds.

As an aside, the exposure to radiation is a major limiting factor for space travel. The ISS is still within the Earth’s magnetic field, and so is somewhat protected. But anything beyond low earth orbit will be slowly fried by radiation. We need to figure out how to shield our ships and colonies if we are going to have a prolonged presence outside of low earth orbit. This, by the way, is why lava tubes may be the best location for stations on the Moon or Mars.

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