Archive for the 'General Science' Category

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

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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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Dec 30 2019

A Climate Change Lost Decade

Published by under General Science

It’s fun and interesting to look back over the last decade and think about what has happened and how far we have come. Round years are arbitrary, but it’s a sufficient trigger to take stock and hopefully gain some perspective on the medium course of history. There is a lot to say about the 2010s, and I may take the opportunity to say more, but I want to discuss in this essay what is perhaps our greatest challenge and disappointment over the last decade. In many ways this has been a lost decade for climate change mitigation.

Over the last decade the scientific evidence (and resulting consensus) that the planet is warming, that humans are the primary driver of this trend, and that the consequences are not likely to be good, has only become greater. The last five years have been the hottest five years on record, and this has been the case for most of the last decade. The year 2016 was the hottest, because it was an El Niño year (short term fluctuations will still be overlaid on top of the longer term trend) but the trend is unmistakable. The story of the world’s ice is more complex, with greater regional and year-to-year variations, but total global ice has been decreasing, and if anything accelerated over the last decade. The Greenland ice sheet in particular experienced accelerated melting. As a result there is a real and growing scientific consensus, north of 97% among relevant scientists, that anthropogenic climate change is happening.

We are also experiencing more extreme weather events. We are seeing more droughts, fires, heat waves, and more powerful storms. In the last decade it become clear that, while the worst consequences of climate change are decades and even centuries in the future, we are starting to see real consequences now.

Economists have started to weigh in as well. Numerous studies were published over the last decade, concluding that – climate change will cost the world many billions of dollars and will reduce economic growth, costing even more. Further, the option of allowing climate change to happen and adapting to the results will likely be the costliest option. In addition to the monetary cost, there is a quality of life cost. Extreme weather causes displacement, psychological trauma, and social upheaval. If you think we are having a refugee crisis now, just wait as flooding increasing and more locations become essentially uninhabitable.

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Dec 19 2019

Sequestered Life

Published by under General Science

Researchers may (and I emphasize “may”) have found life in isolated underground pockets of water in South African mines.  What makes this potential find interesting is that this water has been isolated for about 2 billion years. Scanning electron microscopes have found what researchers believe may be a dividing bacterium. If this is confirmed it will be an exciting discovery for a few reasons.

But first – what do we know now? The water was collected from isolated pockets underground. The water is about 7 times as salty as sea water and can get up to about 54 degrees C. This is right at the limit for known extremophiles, but it is possible for bacteria or archaea to exist in these conditions. The evidence for possible life comes mainly from the microscopic images, which are suggestive but not definitive. One of the researchers, Devan Nisson, a graduate student, noted that “It’s possible the shapes were minerals.”

This would not be the first time that geological structures were confused for life. In 1996 researchers famously announced possible signs of life in a meteorite from Mars. Over 20 years later that claim is still not generally accepted. While there remains some controversy, the consensus is that the tiny structures are minerals, not microbes.

Making the claims for life in the South African mines at least plausible is the fact that there are nitrates and sulfates in the water, which could potentially be used by microbes as an energy source. There are abundant small organic acids, which could serve as building blocks and nutrients. So while extreme, it is possible that this water could support life.

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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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