Archive for the 'General Science' Category

Oct 03 2023

Nobel Prize for Attosecond Physics

Published by under General Science

One attosecond (as) is 1×10−18 seconds. An attosecond is to one second what one second is to the age of the universe. It is an extremely tiny slice of time. This year’s Nobel Prize in physics goes to three scientists, Pierre Agostini, Ferenc Krausz, and Anne L’Huillier, whose work contributed to developing pulses of light that are measured in attoseconds.

Why are such short pulses of light useful? Because they allow for experiments that capture the physical state of processes that happen extremely fast. In particular, they are the first light pulses fast enough to capture information about the state of electrons in atoms, molecules, and condensed matter.

Anne L’Huillier, only the fifth woman to win the Nobel Prize in Physics, discovered in 1987 that when she shined infrared light through a noble gas it would give off overtones, which are other frequencies of light. The light would give extra energy to atoms in the gas, some of which would then radiate that energy away as additional photons of light. This was foundational work that made possible the later discoveries by Agostini and Krausz. Essentially these overtones were harmonic frequencies of light, multiples of the original light frequency.

L’Huillier and her colleagues later published in 1991 follow up work explaining a plateau observed in the harmonic pulses of light. They found that the high-harmonic generation (HHG) plateau was a single electron phenomenon. At the time they proposed that, in theory, it might be possible to exploit this phenomenon to generate very short pulses of light.

In 2001 both Krausz and Ferenc, in separate experiments, were able to build on this work to produce attosecond scale pulses of light. Krausz was able to generate pulses of 650 attoseconds, and Ferenc of 250 attoseconds. Here are some technical details:

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Sep 28 2023

Coal vs Natural Gas

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In the last 18 years, since 2005, the US has decreased our CO2 emissions due to electricity generation by 32%, 819 million metric tons of CO2 per year. Thirty percent of this decline can be attributed to renewable energy generation. But 65% is attributed to essentially replacing coal-fired plants with natural gas (NG) fired plants. The share of coal decreased from 50% to 23% while the share of NG increased from 19% to 38%. Burning coal for energy released about twice as much CO2 as burning NG. Plus, NG power plants are more efficient than coal. The net result is that NG releases about 30% of the CO2 per unit of energy created as does coal.

But – the picture is more complicated than just calculating CO2 release. The implications of a true comparison between these two sources of energy has huge implications for our attempts at reducing climate change. It’s clear that we should phase out all fossil fuels as quickly as possible. But this transition is going to take decades and cost trillions. Meanwhile, we are already skirting close to the line in terms of peak warming and the consequences of that warming. We no longer have the luxury of just developing low carbon technology with the knowledge that it will ultimately replace fossil fuels. The path we take to get to net zero matters. We need to take the path that lowers greenhouse gas (GHG) emissions as quickly as possible. So when we build more wind, solar, nuclear, hydroelectric, and geothermal plants, do we shut down coal, natural gas, or perhaps it doesn’t matter?

If we look just at CO2, it’s a no-brainer – coal is much worse and we should prioritize shutting down coal-fired plants. This may still be the ultimate answer, but there is another factor to consider. NG contains methane, and methane is also a GHG. Per molecule, methane causes 80 times the warming of CO2 over a 20 year period. So any true comparison between coal and NG must also consider methane. (A little methane is also released in coal mining.) But considering methane is extremely complicated, and involves choices when looking at the data that don’t have any clear right or wrong answers.

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Jul 07 2023

GMOs and Butterflies

Published by under General Science

Are attitudes towards genetically modified organisms (GMOs) in our agriculture softening? Back in 2015 a Pew survey found that the gap between public opinion and that of scientists was greatest on acceptance of GMOs (more than any other topic surveyed), with a 51% gap. But more recent data shows declining opposition. Regulators are also softening their stance, with Mexico walking back a ban on GMO corn from the US, and the EU considering softer rules on GMOs. Some countries, like the US, have also adopted new terminology, such as bioengineered, and carved out separate rules for crops made with altered genes but not with transgene insertions.

We still have a way to go, and there is still enough opposition to slow adoption of useful agricultural technology. I like to think this is because the science is slowly winning the day. I do think many environmentalists have their heart in the right place, but sometimes get distracted by ideological positions, such as an aversion to anything “unnatural” or high tech. But if the stakes get high enough, the more moderate environmentalists can change their position. I think we are seeing this with nuclear power and the need to combat global warming. And I think we are seeing this with GMOs and the need to feed the world without destroying the environment. The benefits of GMOs are ultimately just too great to ignore.

But there is a lot of inertia in the anti-GMO propaganda that Greenpeace, the organic lobby, and others have been spreading for two decades. I was just recently asked about one specific claim that reflects the nature of this propaganda and how sticky it can be – aren’t GMOs killing the butterflies? The short answer is no, but as always the full story has lots of details. Here is a typical headline from the Environmental Working Group (who I personally find to be more ideological than science-based) – GMO-Linked Herbicide May Doom Monarch Butterflies. This framing was lazily reproduced by most mainstream reporting, but it is nothing but anti-GMO propaganda.

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Mar 31 2023

T-rex Had Lips

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One of the challenges of paleontology is that we are trying to infer and entire animal just from the hard parts that fossilize, mostly bones and teeth (and sometimes just teeth). But if we look at animals today there are a lot of details we could not guess from their bones alone – the mane of a lion, the humps on camels, or the amazing display of peacocks. Soft tissue is rarely preserved, so in many cases we simply have to guess. If we look at the classic depictions of dinosaurs, we see creatures that are all drab in color and don’t have any significant soft-tissue adaptations. We are getting better and inferring color from fossilized melanosomes. We are also discovering that many dinosaurs had feathers, and those feathers were probably colorful. In fact, that clade (just think of birds) have lots of integumentary adaptations, not just feathers. Turkeys are a good example. It’s just as likely, therefore, that dinosaurs had lots of interesting integumentary structures hanging off of them.

A recent study highlights one method that scientists can use to gain more information about the soft tissue of dinosaurs. They looked at the teeth of T. rex, crocodilians, and lizards. Their question was – did T. rex have a toothy smile like an alligator, or fleshy lips covering their teeth like lizards? They have been imagined both ways, but Jurassic Park probably solidified the image for many people of a toothy T. rex. There is definitely something more menacing about a grill of visible deadly carnivore teeth.

What they did was look at the teeth, which is the hardest part of vertebrates and fossilize very well. Specifically they looked at the wear on the teeth. If fleshy lips covered the teeth, they would have been protected from wear along the covered surface. When looking at the teeth of crocodilians vs lizards we see this difference. So all we have to do is examine T-rex teeth to see if they have wear patterns that look like a crocodiles or a lizards. They also did an analysis of skull size and tooth length to see if there was also a relationship there. They found:

Contrary to depictions that have dominated for more than a century, they found that theropods, including T. rex, had lips that covered their teeth, leaving them looking more like modern Komodo dragons than crocodiles.

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Mar 07 2023

A Climate Debate Regarding Health Effects – Part IV

Published by under General Science

Part 4

This will be the final installment of this mini-debate about climate change and health effects, following a typical format of each person getting to make a statement and a response. Scott makes a lot of complaints about tone, format and fairness while simultaneously trying to shield himself from any similar criticism. I am going to ignore this aspect of his response, and also anything dealing with the media. Rather I am going to focus on logic and evidence.

First I have to point out that Scott did not refute in any way my primary criticism of his logic – the notion that if climate change is having any negative effects it should be seen in the raw data. Rather, when one factor is part of a complex set of factors we can use statistical analysis to tease out its effect, even if the net effect of all factors are not in the same direction. This is the fatal flaw in his premise and methods, and he just dismissed my criticism and doubled down on this strategy. Saying he is quoting the IPCC is not a defense, when he is simply misinterpreting what they said. They are talking about “contributions” from climate change. He doesn’t want to talk about logic, and wants to force us to accept this incorrect framing. Nope – the framing is wrong, and therefore all of his arguments are not valid.

But let’s also delve into the specific claims. The first meaty claim is that climate models are running hot (a now long-debunked climate denying trope). Climate models are used for various things, including estimating climate sensitivity (the amount of warming that would result from a doubling of pre-industrial atmospheric CO2 levels). There are other ways to estimate climate sensitivity, including using historical data. Estimates have become increasingly precise, and now the consensus of evidence is that sensitivity is between 1.5 and 4.5C. The “hot model problem” that Scott is referring to is that the latest evaluation of climate models from CMIP6 shows that 10 of the 55 models looked at estimated sensitivity at >4.5 C (up to 5.6 C), i.e. “running hot”. The other 45 models are fine, and agree with historical data.

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Mar 06 2023

A Climate Debate Regarding Health Effects – Part III

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Part 3

Hi Steve, and thank you for your timely response, and for even considering hosting this debate. There has been, and continues to be a “blackout” on almost all discussion regarding the science behind climate change. If “The science” is truly “settled”, it is a pretty shaky settlement! Why the blackout then?

I appreciate that you have pointed out some of my quirks that I use in constructing and argument. After all, this is a debate, and of course we come at it with different viewpoints and narratives, which makes debates all the more profoundly important to have. I think we would all agree that listening to other viewpoints other than our own, although may be uncomfortable, nonetheless helps us become more intelligent, enlightened, and wise.

While I do appreciate the pointing out of my biases (which we all have), there was very little substantive rebutting of the information I provided. I did use exact verbiage from the latest IPCC report, so nobody could accuse me of making a strawman argument. If you think I’m setting up a bunch of strawman arguments, I invite you to reach out to the authors of IPCC chapter 11: Human Health: Impacts, Adaptation, and Co-benefits and ask them why they are setting up these supposed confounded strawman arguments for me. If I can’t quote IPCC, the most trusted source of climate change information, then who can anyone trust regarding climate change information? The words I used to base my argument upon are their words, not mine. 

You state: “So Scott’s method is fatally flawed – you cannot just look at raw incidence numbers and declare there is no effect from climate change…But Scott dismisses all of this as “modeling”, which he rejects out of hand, explicitly favoring raw data, which is profoundly naive. He also dismissed data on the risks increased by climate change, again favoring raw data that mixes in many confounding variables.”

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Feb 28 2023

A Climate Debate Regarding Health Effects – Part II

Yesterday’s post was the first in an exchange about the effects of climate change on public health. Today’s post is my response.

Part II

Climate change is a critically important topic for society today, and it’s important that the public have a working knowledge of the facts, causes, effects, and potential interventions regarding climate change, so I am always happy to discuss the topic. Unfortunately, it’s a very complex topic that has been highly politicized and polarized. The science often becomes wrapped up in ideology – the best indication of this is that one’s political affiliation is the strongest predictor of the public’s opinions regarding climate change. The media, as they do in general, is happy to sensationalize the topic and often does not provide good context or background. Scientists have gotten better communicating about climate change, but not enough to override political affiliation.

My sense is the core issue is that the complexity of climate change allows everyone to cherry pick those details that fit their narrative. You can find examples to support whatever narrative you want to believe. You don’t even have to be factually incorrect (although many people certainly are), you just have to be selective in your details and interpretation. Climate change is a Rorschach test of subjective validation and confirmation bias.

I say this all because I think Scott’s narrative comes through very clearly. He contacted me asking fervently for a debate on this specific topic, the health effects of climate change. I thought this was a little odd since I have never written or expressed an opinion about this topic before. It seems he assumed what my position was based on other things I have written about climate change – that I think it’s real, it is primarily being caused by humans, and the effects are likely to be bad for the environment and human civilization. This brings up another aspect of the climate change debate, that people generally take sides and think that everyone fits relatively cleanly into the “for or against” side. Once someone thinks they have detected what side you are on, they then ascribe the entire package of views to you.

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Feb 27 2023

A Climate Debate Regarding Health Effects – Part I

This is the first entry in an exchange between me and Scott Hastings, who requested the exchange. This is his opening arguments. My response will be tomorrow’s post.

 

Part I:

Hi Steven, first of all, I am tremendously grateful to you for taking time to engage with me on this very important topic. Thank you.

I’d like to start by sharing just a few media articles I found that are now over 3 years old:

New York Times: November 13, 2019 “Climate Change Poses Threats to Children’s Health Worldwide

ABC News Australia: November 5, 2019 “11,000 scientists declare climate emergency warning world faces catastrophic threat

CNN: November 12, 2019 “The climate crisis will profoundly affect the health of every child alive today,

Wired: November 13, 2019 “How the Climate Crisis Is Killing Us, in 9 Alarming Charts, A new report from over 100 experts paints a devastating picture of how climate change is already imperiling human health.”

We are both physicians, so I don’t want to leave out the American Medical Association statement on climate change.

I think you get the point…We are daily inundated with a “climate emergency” just around the corner.  It also seems that all the experts (at least 97% anyway) are in some general agreement about the “devastating catastrophe” lurking somewhere out there. However, the official IPCC-5 report seems to be a whole lot less confident than the headlines mentioned above.

My aim is to take exact verbiage from IPCC-5, then apply the most up to date scientific literature available to cross-check their stated claims. Since I’m a physician, I am specifically interested in health outcomes as a result of climate change. I am looking at global health trends (since this is a global phenomena), as well as trends in global natural events like floods, fires, and hurricanes as these obviously contribute to health outcomes.  It’s simple really, in our world of experts, nobody needs to be an expert at opening the newspaper the morning after the superbowl to see who won the game. In this case, the “newspaper” is going to be scientific research literature based on global observational trends from generally that was published in the past 6 years. What I will not include is modeling studies. That’s like trying to predict who is going to win the superbowl. I’m not interested in that.  Just real-world objective observations found on google scholar or pubmed. I’m only interested in who won the superbowl, not in some supposed “superbowl prediction expert”.

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Jan 24 2023

Bacteria That Eat Plastic

Published by under General Science

The world produces about 380 million tons of plastic every year, and half of that is single use plastic. This figure is projected to increase by 70% by 2050. A 2017 study found that of all the plastic produced, “9% of which had been recycled, 12% was incinerated, and 79% was accumulated in landfills or the natural environment.” Current practices are unsustainable, as a lot of this plastic ends up in the oceans and elsewhere in the environment. Researchers are increasing looking to bacteria as one potential solution to this problem.

Recycling alone is not a viable solution. Currently, the main effect of recycling plastic is to create a false sense that the problem is being addressed. Plastic is not really recycled in a full circular process. A relatively small portion of plastic is broken down and then remanufactured into lower quality plastics that cannot be recycled. The ultimate fate of all plastics is still the incinerator (not good for the environment), landfills, or the oceans and other environmental locations. What are the potential solutions to this situation?

One solution is to use less plastic. But this is a complex suggestion. Single use plastic is the most common target, and there is a lot of wasteful use that certainly can be reduced. But half of plastic produced is not single use, and a lot of plastic is necessary for certain applications (such as sterile medical use). As always, you also have to consider the alternatives – what will replace this plastic? Sometimes there is an obvious and good solution. In many beverage applications, aluminum can replace plastic and is more recyclable.  Glass is another alternative material. But this approach will only get us so far.

Part of the problem is that plastic is cheap to mass produce, and it works very well for the intended applications. It’s cheaper to make virgin plastic than to recycle old plastic. This reality feeds the problem.

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Jan 03 2023

2015 to 2022 Eight Warmest Years on Record

Happy New Year to all my readers.

Early in each new year I like to see what the preliminary reports are for the climate over the past year. Final number crunching won’t be available for months, and it may take more than a year for the final tweaks to be reported and reviewed. But we do have a preliminary estimate of the temperature over the last year. The World Meteorological Organization reports:

The global average temperature in 2022 is estimated to be about 1.15 [1.02 to 1.28] °C above the 1850-1900 average. 2015 to 2022 are likely to be the eight warmest years on record. La Niña conditions have dominated since late 2020 and are expected to continue until the end of 2022. Continuing La Niña has kept global temperatures relatively «low» for the past two years – albeit higher than the last significant La Niña in 2011.

It looks like 2022 will be the fourth hottest year on record globally. Some specific locations had their warmest year, such as the UK and Spain (and perhaps most of Europe). As the WMO points out, we are in the middle of a La Niña cycle, which brings cooler temperatures globally. That is a short term fluctuation on the longer term trend. This also means that as we shift into an El Niño cycle we are likely to break new records.

I feel compelled to point all this out (as I am sure many scientists and science communicator will) because it is a critically important piece of information. But I also want to put it into a broader long term context. I have been engaged in skeptical activism now for 27 years, and followed many skeptical topics for longer than that. There is one extremely important pattern that emerges when you cover a topic for a long time – scientifically valid concepts tend to not only accumulate evidence but the evidence gets better and builds on itself. Meanwhile, pseudosciences do not display this pattern. They tend to go around in circles with low quality evidence. You can see this pattern across multiple disciplines.

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