Archive for the 'General Science' Category

Sep 22 2020

GMO Crops and Yield

The issue of genetically modified organisms is interesting from a science communication perspective because it is the one controversy that apparently most follows the old knowledge deficit paradigm. The question is – why do people reject science and accept pseudoscience. The knowledge deficit paradigm states that they reject science in proportion to their lack of knowledge about science, which should therefore be fixable through straight science education. Unfortunately, most pseudoscience and science denial does not follow this paradigm, and are due to other factors such as lack of critical thinking, ideology, tribalism, and conspiracy thinking. But opposition to GMOs does appear to largely result from a knowledge deficit.

A 2019 study, in fact, found that as opposition to GM technology  increased, scientific knowledge about genetics and GMOs decreased, but self-assessment increased. GMO opponents think they know the most, but in fact they know the least.  Other studies show that consumers have generally low scientific knowledge about GMOs. There is also evidence that fixing the knowledge deficit, for some people, can reduce their opposition to GMOs (at least temporarily). We clearly need more research, and also different people oppose GMOs for different reasons, but at least there is a huge knowledge deficit here and reducing it may help.

So in that spirit, let me reduce the general knowledge deficit about GMOs. I have been tackling anti-GMO myths for years, but the same myths keep cropping up (pun intended) in any discussion about GMOs, so there is still a lot of work to do. To briefly review – no farmer has been sued for accidental contamination, farmers don’t generally save seeds anyway, there are patents on non-GMO hybrid seeds, GMOs have been shown to be perfectly safe, GMOs did not increase farmer suicide in India, and use of GMOs generally decreases land use and pesticide use.

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Sep 17 2020

Ice Age Bear Found in Melting Permafrost

Published by under General Science

On the surface this is a story of a fantastic paleontological find. Reindeer herders discovered a well-preserved brown bear in the Russian Arctic, released from melting permafrost. The bear is intact, with lots of preserved soft-tissue, and is therefore of extreme scientific value.

But behind the story there is a deeper and concerning one – wait, isn’t “melting permafrost” an oxymoron? Isn’t permafrost supposed to be permanent? Not exactly. The technical definition of permafrost is any ground that is frozen for at least two years straight. Less than that and it is considered seasonally frozen. But much of the permafrost in the world has been frozen for hundreds of thousands of years. The oldest ice is in Antarctica, believed to be 1.5 million years old.

The bear is estimated to be between 22,000 to 39,500 years old. That is also the age of the ice in which it was frozen, and that ice is melting. The bear is also not the first ice-age remains to be discovered in the Arctic permafrost. In recent years scientists have also found dogs and woolly mammoths melting out of the ice. Of course fluctuations in the extent of the permafrost is nothing new, when we consider the a long time frame. But the Arctic permafrost particularly appears to be melting at an alarming rate. And of course, this is thought to be due to global warming.

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Jul 24 2020

Climate Sensitivity

Published by under General Science

There are various (non-mutually exclusive) ways to deny science. You can cherry pick the data and sources you like – there is always someone on the fringe with an opinion counter to the mainstream. You can use the all-purpose method of invoking a grand conspiracy theory. You can replace scientific opinion with pseudoscience. Or, if you have sufficient background scientific knowledge, you can magnify the uncertainty and disagreements that exist in all theories to make it seem like the core claims are in doubt, when they aren’t.

One of the primary targets for those who deny climate change and rely on the latter method is to focus on the notion of climate sensitivity. It is clear that CO2 is a greenhouse gas, only the most hard-core conspiracy theorist climate deniers deny that basic fact. Therefore, increasing the amount of CO2 in the atmosphere should increase this warming effect, and warm the planet. There are obviously many more technical layers to the process, including positive and negative feedback loops, other greenhouse gases, reactive gases that amplify the effect, and other factors that influence the climate. But the simple fact that increasing CO2 increases warming is essentially correct and non-controversial among experts.

So if you want to claim that CO2 release from human activity is no problem, you need to argue that the magnitude of the effect is too small to worry about. This is what climate sensitivity is – specifically defined as the amount of warming from pre-industrial levels that would ultimately result from a doubling of CO2 in the atmosphere. If we look at the last million years CO2 level fluctuated from around 200-280 ppm (parts per million). Over the last 100 years this amount has increased steadily, and is now over 410 ppm. How long it will take to double the CO2 depends on what we do, but unless there is a major change to our energy and industry infrastructure, we will get there by the end of the century.

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Jul 06 2020

Feeding Animals Insects

Published by under General Science

The current world population is 7.8 billion people. We are expected to reach 10 billion by 2057, which, let’s face it, is right around the corner. That is a lot of people to feed. We don’t produce enough food now to feed that many people, and we are already using almost all the available arable land (this is a complex topic, but I go over it in detail here). What are the possible solutions?

Some argue for population control, and there is a reasonable argument to be made for leveling off and stabilizing human populations, even allowing them to drift down a bit. I don’t want to go into detail on this issue here, just to quickly say I reject arguments for radical population control, or things like allowing mass starvation to occur. But I support efforts such as lifting people out of poverty and affording more rights to women, both measures being shown to reduce population increase.

Another offered solution is to reduce food waste, and this is a noble effort. However, there is no magic wand we can wave to make this happen. Food waste is built into the system, and a major cause is the limited shelf life of food. It spoils. But there is unnecessary waste in the system, and we can do a better job of making sure as many calories end up consumed (by people or animals) as possible, and the rest is recycled as fertilizer. But this isn’t going to solve the problem.

This leaves us with food production – we need to produce more calories of food in order to meet growing demand. This is going to require a global effort, and the introduction of new technology. I have argued for the necessity of GMOs in order to meet growing demand for food while minimizing land use. But we have to produce not only more food, we need to produce food smarter – making sure that our resources (especially land) are being used optimally.

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Jun 22 2020

A Green Recovery

Published by under General Science

I don’t like the headline of this article: World has six months to avert climate crisis, says energy expert. It’s accurate – a climate scientist does indeed say that, but it is focusing on an extreme end of expert opinion, and is misleading without context. I know, headlines are attention grabbers and often not written by the author of the article, I just find it all annoying.

In any case – what is this guy, Fatih Birol, executive director of the International Energy Agency, talking about? His point, which is an interesting one, is that the pandemic provides an opportunity to accelerate reduction in carbon emissions. This is because the world is set to spend “$9tn (£7.2tn) globally” on the economic recovery, much of it focused on job preservation and creation. What if we spend some of that money on job creation in the green energy sector? That is where the “six months” comes from. It is not based on science, on when we spend our carbon budget or when getting to a climate tipping point becomes inevitable. Rather, it is the time frame of determining how those trillions of economic recovery dollars will be spent. Birol argues this is our last realistic chance, from this political perspective, to make the dramatic changes to our economic and energy infrastructure that averting the worst of climate change requires.

He does have a point, although I would argue that it is never theoretically too late. At any point the world could muster the political will to deal properly with climate change. Sometimes we do reach inflection points in public opinion. But the pessimistic view is that this is unlikely to happen with climate change. The political will probably will not manifest until after it is too late.

There are several reasons for my pessimism. One is that the effects of climate change will not generally be felt until years after the carbon release that causes it. We are already, arguably, feeling the effects of climate change, but not in a way that is overwhelmingly undeniable, at least to enough people to make a difference. Further, there are vested interests in the status who that spend a lot of money on disinformation and political lobbying. They don’t have to “win” the argument in the end, only cause enough fear and doubt to delay action.

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Apr 07 2020

Who Speaks for the Insects

Published by under General Science

Dr. Matt Hill is filling the role of the Lorax for insects. They are a critical part of our ecosystem, and they are experiencing a long term decline. I know there is a lot to worry about in our complex world, and insects may not immediately jump to near the top of the list, but they are important, and also an index of ecological change.

We are used to thinking of insects as pests, just as we are used to thinking of bacteria as germs that cause infections. But most species of bacteria or completely neutral when it comes to humans, and some are actually beneficial (even critical). The same is true for insects. Only a relatively small percentage are pests (which itself is a relative term), while most go about their lives indifferent to humanity. Some species are directly beneficial, like pollinators. Regardless of their relationship to humanity, insects are a critical part of the ecosystem. Insects have the largest biomass of all animals (although animals as a group are dwarfed by plants and to a lesser extent bacteria).

A 2019 study concluded that 40% of insect species were at risk of extinction over the next few decades. Other studies show a significant decrease in insect biomass over the last 50 years. This is a loss of a critical source of food for the entire ecosystem.  Hill and his colleagues (Pedro Cardoso is first author) now have published a review of this research, warning the world of this critical decline, summarizing possible causes, and recommendations some steps individuals can take as partial solutions. They summarize the causes:

We are causing insect extinctions by driving habitat loss, degradation, and fragmentation, use of polluting and harmful substances, the spread of invasive species, global climate change, direct overexploitation, and co-extinction of species dependent on other species.

Like most stresses on the ecosystem, the biggest factor is land use. Recent estimates are that humans actively use almost half of all land on Earth, mostly for agriculture and ranges for domestic animals. Some of what is left is also “semi-natural”, meaning that it is not directly occupied or used, but is not “pristine” wilderness either. And of course the entire planet is now affected by things like pollution, climate change, and the introduction by human activity of invasive species. We are putting tremendous stress on ecosystems.

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Mar 10 2020

Day Was Shorter 70 Million Years Ago

What does an extinct mollusk have to do with the Moon? This is one of those amazing science stories that ties together multiple disciplines and lines of evidence into one elegant narrative. In this case a detailed analysis of a 70 million year old mollusk shell has given scientists a critical piece of information that will help them model the Earth-Moon system.

Let’s start with the Moon – astronomers know that the Moon is moving farther away from the Earth at a constant rate, 3.82 centimeters per year. We can precisely measure this because the Apollo missions left corner reflectors on the surface of the Moon, and we can shoot lasers off those reflectors and measure the round-trip travel time. Because scientists have also precisely measured the speed of light, we can use this round-trip time to calculate the exact distance between the laser on Earth and the reflector on the Moon.

Why is the Moon moving away from the Earth? In a word – tides. Tidal forces from nearby large objects causes a bulge to form. We are most familiar with this phenomenon because of the bulge in the ocean caused mostly by the Moon (and to a lesser degree the Sun) which we experience locally as a rising and falling of the sea. The tidal bulge on the Earth is slightly ahead of the Moon in its orbit, because the Earth is spinning faster than the Moon. This leading bulge tugs slightly on the Moon, accelerating it into a higher orbit farther from the Earth. This represents a transfer of momentum from the Earth to the Moon via gravity, which not only moves the Moon farther away, but slows down the rotation of the Earth (and the conservation of angular momentum is obeyed).

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Mar 02 2020

A Claim for Dinosaur Proteins and DNA

Another paper has been published in the simmering controversy over whether or not proteins, and even DNA, can survive millions of years in well-preserved dinosaur (non-avian dinosaurs, that is) fossils. The paper looks at cartilage from a duck-billed dinosaur, a young Hypacrosaurus stebingeri. The authors claim:

“…microstructures morphologically consistent with nuclei and chromosomes in cells within calcified cartilage. We hypothesized that this exceptional cellular preservation extended to the molecular level and had molecular features in common with extant avian cartilage. Histochemical and immunological evidence supports in situ preservation of extracellular matrix components found in extant cartilage, including glycosaminoglycans and collagen type II. Furthermore, isolated Hypacrosaurus chondrocytes react positively with two DNA intercalating stains.”

Let me say right away that these claims are controversial, but what would they mean if true? If we could examine the structure of proteins and DNA from >65 million years ago, in well-preserved dinosaur fossils, then the world of molecular biology would extend back to that era. Molecular examination has had a significant impact on paleontology – but it has limits. So far the oldest DNA sequenced from a fossil is from a 700,000 year old horse frozen in ice. The oldest protein so far confirmed is from a rhino 1.7 million years old. This means that if the current claims are true, DNA can survive in fossils 100 times longer than the current record would indicate.

This is also not the only source of information from which to estimate the lifespan of DNA. Researchers have examined DNA from Moa specimens in New Zealand, over a span of about 8,000 years. This allowed them to estimate the half-life of DNA, the time over which about half the bonds would be broken. Their estimate – 521 years. This means that all the chemical bonds in a DNA molecule would be gone after 6.8 million years, but having any fragments along enough to sequence would be gone after about one million years. This aligns nicely with the evidence from actual fossils. So claiming DNA from >65 million years would be extraordinary, to say the least. This is why most scientists remain skeptical of these claims.

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Jan 23 2020

Asteroid Not Volcanism Killed the Dinosaurs

Published by under General Science

The popular belief is that an asteroid impact caused the mass extinction at the K-Pg (formerly K-T) boundary 66 million years ago. This is the mass extinction that killed off the non-avian dinosaurs along with 75% of species on Earth. However, in reality there is a raging scientific debate about the exact causes of the extinction event. The two contenders are the asteroid impact, which we know happened right at that time, and extreme volcanism at the Deccan traps in what is now India.

Scientists fall along a spectrum in this debate. At one end there are those who believe the asteroid was the main event, and the volcanic eruptions played little to no role. At the other end are those who believe that climate change caused by the volcanoes, with both global warming from the CO2 and acidification of the oceans, was the main driver of extinction. The asteroid impact, at most, was the coup de grace. In between are those who feel that both events were important to extinction to varying degrees, and we’re just trying to sort out their relative contributions.

The evidence has gone back and forth on this debate, although I think it has been strongly favoring the asteroid impact as the dominant factor. A new study contributes to this debate, and heavily favors the asteroid impact. In fact, the authors argue that their evidence suggests the volcanism at the Deccan traps played no role at all in the extinction. The modeled the outgassing from the Deccan traps and compared the models with the evidence to see which one fit the best. This is what they found:

We found support for major outgassing beginning and ending distinctly before the impact, with only the impact coinciding with mass extinction and biologically amplified carbon cycle change. Our models show that these extinction-related carbon cycle changes would have allowed the ocean to absorb massive amounts of carbon dioxide, thus limiting the global warming otherwise expected from postextinction volcanism.

Essentially the outgassing from the Deccan traps started, according to their model that best fits the evidence, 350,000-200,000 years prior to the impact and extinction. This caused a global warming event of about 2 C, which further lead to a migration of many species toward the poles. However, the outgassing and warming stopped prior to the extinction, the Earth cooled back to its prior baseline, and the various species returned to their previous locations. So the ecosystem has returned to its prior baseline, without any mass extinction, and then the asteroid hit and caused the mass extinction all by itself.

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Jan 14 2020

Communicating The Consensus

Published by under General Science

Science communication is an evolving art, backed by some interesting research. However, my overall take on the state of the research is that it is mostly telling us the various ways in which we fail, rather than how to succeed. The latest target if scicomm handwringing is “consensus messaging.” How do we, and should we, communicate the scientific consensus to the public?

This issue is probably most salient to communication about global warming. Those who deny the scientific consensus on AGW frequently deny that there is a consensus and/or deny that a scientific consensus is even meaningful. How should we address this situation. In 2018 Russil argued that consensus messaging is generally ineffective. Instead we should focus on the victims of climate change:

“If we recognize that climate change danger will be mediated by questions of migration, dislocation and refuge, and if climate change communication abandons the legacy of consensus messaging to involve those affected by danger, how might our work unfold differently?”

It’s fine to try new approaches, but my problem with this argument is that essentially nothing works when it comes to changing minds on AGW, and so the fact that any one strategy does not work doesn’t really tell us anything about that strategy, or favor any other.

The concept of consensus does, in fact, exist in science. I wrote about it previously here and here. If the vast majority of scientists agree on some scientific conclusion, that is a consensus. That much is historically undeniable, so the strategy is often to switch to the position that a consensus is meaningless. That’s not how science works. To bolster this position often an example of when a scientific consensus was wrong is brought up. These examples, however, never work to establish the anti-consensus position.

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