Archive for the 'General Science' Category

Nov 12 2020

Biden’s Climate Plan

Despite Trump’s attempt to break US democracy in order to alter reality to his liking, Joe Biden will be sworn in as the next president. This has obvious implications for US’s plans for tackling climate change. The first is that we will now have an executive branch that recognizes science, that climate change is real, and will actually try to do something about it. Immediately this means rejoining the Paris accord, and appointing people to the energy and environmental agencies that are not climate change-denying coal executives.

Biden’s plan (which is not the green dew deal) is to have our energy infractructure be net zero carbon emitting by 2035 and the entire country to be net zero by 2050. That is ambitious, and if I had to bet I would say we will fall short of this goal (although I hope I’m wrong), but it is a reasonable goal. How, theoretically, will we get there?

First, although it is politically risky to say so bluntly, we have to wean ourselves entirely off of fossil fuel. Biden acknowledged this during the second debate – end fossil fuel subsidies, and phase out fossil fuels over time. Given his stated goal, that would mean phasing out coal, oil, and gas by 2035. Is that even feasible? Currently, if we look only at power production, the mix of sources in the US is: fossil fuels 62.6%, Nuclear 19.6%, and renewables (wind, solar, biomass, geothermal, hydroelectric) 17.6%. The question is, in 2035, what do we want our energy mix to look like and how can we get there?

The path to getting there is not insignificant, because we will be emitting carbon along the way. One controversy is fracking and natural gas, which is cleaner than coal, but still a fossil fuel. Should we phase out coal quickly by replacing it with natural gas plants, or skip over natural gas and go straight to renewables and nuclear? If we could skip natural gas that would be optimal, but realistically the perfect may be the enemy of the good. Natural gas may be an effective temporary measure to quickly eliminate coal while we are transitioning to net zero energy production. But I am open on this question.

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Nov 05 2020

Crop Yield with Higher CO2

Published by under General Science

One of the arguments often put forward by global warming deniers is that CO2 is not a pollutant, and in fact higher CO2 is good for crop yield. This point is invoked during their shifting defense – the planet is not warming; well, OK, it’s warming but it’s not due to humans; alright, humans are to blame but this won’t necessarily be a bad thing. See – CO2 is good for plants.

While this core claim is somewhat true, it needs to be put into perspective. First, as a risk vs benefit, raising global CO2, with all the downstream negative effects, is a terrible way to increase crop yield. But a new study looks at 30 years of data to address the underlying premise – what is the net effect of rising CO2 levels on crop production? The short answer is, while some crops increase yield, the overall effect is complicated.

The first distinction we need to make is between C3 and C4 crops, which refers to the type of photosynthesis used. In the C4 pathway some of the energy is used to concentrate CO2 in the chloroplasts, resulting in a higher efficiency of turning light into energy. C4 plants include corn and sugarcane. For these crops there is no benefit in yield from higher CO2 levels. C3 plants do not have this adaptation and they are more dependent on ambient CO2 levels, and they do benefit from higher CO2. But there are some important caveats to this.

What the study showed is that the overall average increase in yield among C3 crops to rising CO2 in the last 30 years is 18% “under non-stress conditions”. That last bit is important because that increase is significantly reduced if there is not enough nitrogen available to take advantage of the higher CO2, which is the case in most of the non-industrialized world. Further, the rising temperature that accompanies the higher CO2 decreases the yield, and also increases loss to pests. Wet conditions, which are also important for yield, reduce the benefit from CO2, however, which is greatest under drought conditions. So overall there has been a modest increase in yield in some crops in industrialized farming where increased nitrogen if available.

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Oct 26 2020

Murder Hornets Found and Destroyed

Published by under General Science

Invasive species can be a serious problem. They may lack predators to keep their populations in check, and some may be predators themselves, preying on species that cannot defend against them. Eventually a new equilibrium will be reached, but in the meantime this can be destabilizing and in the long term will reduce diversity. The “invasive species of the year” for 2020 has to be so-called “murder hornets”.

The proper name for this insect is the Asian giant hornet (Vespa mandarinia), and as the name implies it is native to temperate and tropical regions of Asia. It is the largest hornet species on Earth. As insects go, they are huge – “The hornet has a body length of 45 millimetres (1 3⁄4 inches), a wingspan around 75 mm (3 in), and a stinger 6 mm (1⁄4 in) long, which injects a large amount of potent venom.” Their nickname, “murder hornet”, derives from their behavior. They prey upon other insects, mainly honey bees, but also mantises and even other hornets. If they enter a honey bee nest, even a few hornets can wipe out the entire nest in several hours. They typically kill by decapitating the bees with their large mandibles. The bees defenses are all but useless – their stingers too small to penetrate the hornet’s armor.

They are not much of a direct threat to humans. Only about 40 people per year are killed in Asia from giant hornet stings. They are not generally aggressive, but will attack if they are threatened. They can sting multiple times, and their stinger is long enough to penetrate typical beekeeping suits. Their venom is known for producing incredible pain, and can cause some local tissue damage. So even if you don’t die, being stung will not be a pleasant experience. Their real threat to humans is indirect – from the threat they represent to our pollinators.

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Oct 19 2020

Biodiversity Matters

I consider myself a skeptical environmentalist, which is why I was really annoyed by the book by the same name by Bjørn Lomborg. The problem with Lomborg’s book was not the notion of reviewing the science behind the big environmental issues, but rather that he did such a poor job his treatment amounted to denialism, not skepticism. It as so bad, in fact, that Scientific American was motivated to dedicate an entire issue to systematically debunking his claims. This, of course, is part of a larger trend of tainting the word “skeptic” by using it to refer to science deniers and contrarions (and yes, there is a difference and denialism is a thing).

I am an environmentalist in the way that we should all be environmentalists – we should care about the biosphere in which we live. It is literally the only one we have. It is probable that human civilization will never have another, ever. Think about that. Interstellar travel will likely never be practical, and even if we can figure out a way to get to nearby systems, we will not find another Earth. Finding a world that is “earth-like” would require science-fiction level faster-than-light travel which may never be possible, and if it is will not happen anytime soon. Even then, there is a huge difference between “earth-like” and Earth. Terrforming other worlds in our solar system is also very difficult, and will take thousands of years if it is practical at all. So except for far future unpredictable scenarios – this is it. Our efforts are best spent preserving the world that is literally perfect for us, because we evolved here.

Beyond just surviving, I also love nature, perhaps more than the average person. Although people in general have an affinity for nature, and studies show that people are generally happier and healthier when they have exposure to nature. But as human civilization has grown, especially in the las century, we have displaced many natural ecosystems and impacted the environment in such a way as to stress many natural ecosystems. This is a serious issue because of, in a word, biodiversity.

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Oct 06 2020

Undocumented Immigrants and Crime

Published by under General Science

We live in a democracy, and people have different perspectives, interests, and values. This means we can honestly disagree on questions about how to run our society, and the political process is supposed to work out those differences through compromise and democratic processes. However, the political process should be based on objective facts as much as possible. Senator Daniel Moynihan is quoted as saying, “Everyone is entitled to their own opinions, but they are not entitled to their own facts,” or some variation of that basic idea. If we lose the objectivity of facts, if everything is opinion, then the democratic process breaks down. There is no longer any common ground for discussion. In fact, what seems to be happening is that not only has fact devolved into opinion, opinion has become an alternate reality constructed and maintained through conspiracy theories.

Assuming we can get back to a world in which facts exist, let alone matter to some degree, they can very usefully inform public debate on political topics. Facts alone don’t determine political outcomes, because values can still differ, but they help. Let’s take the association between undocumented immigrants and crime as an example.

One of the prominent arguments put forward for aggressive policing of our borders is to stop undocumented immigrants, because they bring “large-scale crime and disease” across the border. But do they? Citing dramatic anecdotes will never give us a meaningful picture of reality. We are a nation of over 300 million people – everything happens somewhere. You can find anecdotes to support any narrative you wish. What we really need is data.

One problem is that undocumented immigrants are – undocumented. This makes it hard to track them and to get data on them. But we do have several lines of evidence that give us at least a partial picture. For example, some studies do surveys of individuals, asking their immigrant status and their involvement with crime. One such study, published in 2017, found that immigrants were 2-3 times less likely to report criminal behavior than demographically matched US born individuals. The two main weaknesses of this approach is that, first, it mixes documented and undocumented immigrants into one category. Second, this tells us only that immigrants report less crime, which may not be the same as engaging in crime.

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Sep 25 2020

Climate Change and Wild fires

Published by under General Science

Psychological research confirms what I have observed anecdotally – that people prefer simple answers to complex ones, and will often settle on a single cause of even complex events. This is why I often jokingly answer questions of, “Is the cause A, B, or C,” with “yes.” That is usually the correct (if unsatisfactory) answer, all of the options are correct to some degree. Assuming there is “one true cause” can also be considered a false choice fallacy, or a false dichotomy.

I most recently did this when asked if the increase in wildfires were are currently experiencing on the West Coast of the US are caused by global warming or bad forest management. The experts agree that both contribute, and a new review of the literature sheds some additional light on this question. The authors reviewed over 100 studies published since 2013. This same group published an earlier review on the causes of the Australian wild fires last year. The conclusion of the new review is that global warming has had an “unequivocal and pervasive” role in increasing the conditions that contribute to wild fires.

As they say, this is not rocket surgery. As the weather gets warmer we are experiencing a greater portion of the year with high temperatures, lower humidity, decreased rain, and increased winds. These are all conditions that contribute to starting and spreading wildfires, making them more likely and more intense when they occur. The result has been the worst fire season on record, with three of the four worst individual fires occurring this year.

Stepping back a bit to the bigger question – is there global warming – this fire season adds to the growing evidence that there clearly is. Average temperatures are increasing with the top 10 warmest years on record all being since 1998, with 2016 being the warmest. It is too early to tell for sure, but 2020 is on track to being one of the warmest years on record as well, and may even break the record as the warmest. Further, global ice is decreasing steadily. Hurricanes are getting stronger. Flooding is increasing. And of course, wild fires are increasing. You could claim that any one of these is a coincidence, or has a separate explanation. But given the totality of evidence, that amounts to little more than special pleading. Climate models predicted all of these things, and they are all happening. Trying to write off each individual item (and others I didn’t mention) may work rhetorically with some, but only when looked at in isolation. The probability that so many events predicted by climate scientists as a result of global warming are actually happening is not some grand coincidence or conspiracy. The Earth is warming.

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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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