Category Archives: Peer Reviewed Article Review

weather control

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Here is some new research on chaos theory and the so-called “butterfly attractor“. The idea is that by making small-scale interactions with the atmosphere, for example by speeding up or slowing down wind turbines, it might be possible to influence the development of extreme events. This is all theoretical and simulation-based at this point, but if it is true it would certainly be easier, more reversible and less risky than schemes such as releasing massive amounts of aerosols into the atmosphere.

climate migration modeling

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Here is one new article on U.S. climate migration modeling, but I wasn’t able to access the conclusions. Going back to this 2020 article, which at least lets you stare at the pictures, major coastal cities like greater Boston, greater New York/New Jersey, Philadelphia, D.C., Jacksonville, Miami, and of course New Orleans are going to be in serious trouble by 2100. Population simulations show a lot of people just migrating inland a county or two, so maybe that is the form the evolution of our cities will take if sea level rise is relatively slow and gradual – protection of a few iconic/historical coastal areas perhaps, coupled with intensifying suburban sprawl in surrounding counties within the metro area? This sounds relatively undramatic, although bland and uninteresting and wasteful of both land and energy. Land use policies, such as zoning and green belts, could be overhauled now in anticipation, or we can just let this happen willy nilly.

It is not clear to me if these articles consider immigration, but I imagine there will be immigration pressure and we could also think about how to handle that in a smart way – which luckily our political system is just awesome at!

back to drugs and crime

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Recently I said my thoughts on the relationship between violence and the drug economy were evolving. Well, here is a paper from Temple University showing evidence that a lot of violence is linked to the drug economy. They look at neighborhoods in Philadelphia that are similar across most variables other than drug activity, and show that the neighborhoods with more drug activity have more violence.

the Simon-Ehrlich bet

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Paul Ehrlich has probably won his 1980 bet with Julian Simon in a number of parallel universes, according to this analysis:

Better lucky than good: The Simon-Ehrlich bet through the lens of financial economics

In 1980, Julian Simon and Paul Ehrlich bet on the future of natural resource prices as a vehicle for their public debate about mankind’s future. Simon ultimately won, and his victory has been used as evidence that innovation can offset material scarcity induced by human economic activity. But does the outcome of the bet truly suggest this? We recast the bet as a short-sale by Simon of Ehrlich’s portfolio of assets, allowing us to carefully analyze the choices made in the bet, including the resources chosen and their amounts and the period of the bet, conditioned on the information available to each man in 1980. We also investigate the role of randomness in the outcome of the bet. We find that, with careful portfolio construction, Ehrlich should win this bet more often than not, validating the age-old adage that it’s better to be lucky than good.

Ecological Economics

Does this mean that humanity as a whole is better off than we maybe “should be” on average? Hard to say.

How much ecological function can urban green space provide?

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This is an important research question, I think, as the world becomes even more urbanized. Here’s a new study:

Vegetation Type and Age Matter: How to Optimize the Provision of Ecosystem Services in Urban Parks

As cities grow, urban greenspace assumes a more central role in the provision of ecosystem services (ESS). Many ecosystem services depend on the interactions of soil-plant systems, with the quantity and quality of services affected by plant type and age. The question, however, remains whether urban greenspace can be included in the same ecological framework as non-urban greenspace. Our previous studies have contributed towards filling this knowledge gap by investigating the effects of plant functional type (evergreen trees, deciduous trees and lawn) and plant age on soil characteristics and functionality in urban greenspace, offering also a comparison with non-urban greenspace. A total of 41 urban parks and five non-urban forest sites within and adjacent to the cities of Helsinki and Lahti (Finland) were included in this project. Path analyses presented in this contribution, combined with a synthesis of previous findings, offer strong evidence that urban greenspace functions similarly to non-urban greenspace. In particular, plant functional types lead to soil environmental modifications similar to those in non-urban ecosystems. Therefore, vegetation choice upon park construction/implementation can improve the quality and quantity of ESS provided by urban greenspace. However, although vegetation modifies urban greenspace soils with time in a fashion similar to non-urban greenspace, the vegetation type effect is greater in non-urban greenspaces. To conclude, our synthesis of previous studies provides science-based guidance for urban planners who aim to optimize ESS in urban greenspaces.

Urban Forestry and Urban Greening

Ecosystem services and ecological function are not exactly the same thing. Ecological function just is. Ecosystem services are what ecological functions do for people, and fit into the mainstream economic analysis framework. Part of the issue in studying this, I think, is scale. If you look only at one site, block, or park in a city, you might conclude that ecosystems services are negligible or un-measurable. If you look at the entire network and how it is connected, you might conclude that the effects are measurable and that there are policy and design choices that could make them better.

Biodiversity is something else again. More biodiversity is not always better, if it consists of more species of rats or coronaviruses, for example. But biodiversity may be a reasonable proxy measure for how the structure of a designed urban ecosystem translates to ecological function. This is useful if ecological function itself turns out to be difficult to measure. And I think the most useful measures might be biodiversity of animals such as insects (bees, butterflies) and birds. Because the plants in urban areas are mostly the ones that people put there. Biodiversity of plants can be improved through design choices, which is a good thing but in measuring that you are largely measuring inputs to the system rather than the resulting state of the system. Measure the animals, and you are measuring the resulting state of the system.

Measuring things that flit and flutter around might seem daunting. Well, you could try to do it with cameras and image processing of some sort. Or if you are interested in insects you can focus on larva, aka caterpillars. Tracking down bee and wasp nests seems a bit more risky, and you might also have a public relations problem trying to explain why more bee and wasp nests would be a good thing. But caterpillars don’t move fast, so trained people should be able to cordon off an area and find and identify them periodically. Let’s say you did this once a week for a year at several defined points in an urban area, especially if land use changes are occurring (or maybe some places they are occurring and some places they are not occurring.) Doing the same thing in nearby forests and/or farm fields might also add worthwhile data. Now you can do some data analysis and modeling, and maybe figure out design or policy choices that would help the little critters while also benefiting or at least not pissing off people or costing them any money. If you want to fund my half-baked research proposal, let me know.

more Peter Turchin

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Here’s a new journal article from Peter Turchin and his Seshat database to empirically test hypotheses about history.

Rise of the war machines: Charting the evolution of military technologies from the Neolithic to the Industrial Revolution What have been the causes and consequences of technological evolution in world history?

In particular, what propels innovation and diffusion of military technologies, details of which are comparatively well preserved and which are often seen as drivers of broad socio-cultural processes? Here we analyze the evolution of key military technologies in a sample of pre-industrial societies world-wide covering almost 10,000 years of history using Seshat: Global History Databank. We empirically test previously speculative theories that proposed world population size, connectivity between geographical areas of innovation and adoption, and critical enabling technological advances, such as iron metallurgy and horse riding, as central drivers of military technological evolution. We find that all of these factors are strong predictors of change in military technology, whereas state-level factors such as polity population, territorial size, or governance sophistication play no major role. We discuss how our approach can be extended to explore technological change more generally, and how our results carry important ramifications for understanding major drivers of evolution of social complexity.

PLOS One

Glancing through the methods confirms my suspicion that big data or machine learning analyses pretty much start from old-school correlation and regression, then branch out (sometimes literally in things called “trees”) from there.

water, energy, and food in macroeconomic models

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Here’s an article on how water, energy, and food fit into macroeconomic models. My basic understanding is that traditionally, they don’t. Production functions focus on labor and capital because these are assumed to explain most of the output, and including water, energy, raw material, and even land prices does not make enough difference to bother with. So the methods exist, but economists generally don’t bother because historical data shows these things don’t make a difference. We have certainly seen short-term and regional price shocks in food and energy that have affected economies. We haven’t really seen a sustained, long-term rise in prices of water, energy, or food, in fact the long term trend has been clearly the opposite. Will climate change begin to reverse this at some point? Or is it already happening but our technology is keeping up? Or is it happening slowly, we are adjusting, but the system is becoming more fragile and we are headed for a sudden panic at some point? Like dead wood building up in a forest – the forest may look okay for a long time, and then one day there is a spark, followed by an intense crisis, and then you are left with ashes…

Critical Reflections on Water-Energy-Food Nexus in Computable General Equilibrium Models: A Systematic Literature Review

The paper analyses how the Water-Energy-Food Nexus is treated in Computable General Equilibrium (CGE) models, discussing their design, importance and possible ways of improvement. The analysis of their structure is critical for evaluating their potential efficiency in understanding the Nexus, which will be particularly effective for gauging the importance of the topic, the reciprocal dependency of its elements and the expected macroeconomic, demographic and climatic pressures that will act on its components. General equilibrium models can be useful devices to this end, as they are specifically built to track interdependencies and transmission effects across sectors and countries. Nevertheless, the review showed that most CGEs in the literature struggle to represent the competing water uses across sectors and, in particular, those concerning the energy sector. Therefore, it highlights the need to resolve this issue as a necessary step toward improving future research.

Environmental Modeling and Software

astrobiologists on what aliens might actually look like

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Well, astrobiologists don’t know what aliens might look like, because they haven’t observed any. But they do have an idea what conditions on other planets (“at least 100 billion in our galaxy alone”) might be like, and by assuming the principles of evolution and natural selection will apply, they can theorize what kinds of organisms might inhabit them.

Darwin’s aliens
Making predictions about aliens is not an easy task. Most previous work has focused on extrapolating from empirical observations and mechanistic understanding of physics, chemistry and biology. Another approach is to utilize theory to make predictions that are not tied to details of Earth. Here we show how evolutionary theory can be used to make predictions about aliens. We argue that aliens will undergo natural selection – something that should not be taken for granted but that rests on firm theoretical grounds. Given aliens undergo natural selection we can say something about their evolution. In particular, we can say something about how complexity will arise in space. Complexity has increased on the Earth as a result of a handful of events, known as the major transitions in individuality. Major transitions occur when groups of individuals come together to form a new higher level of the individual, such as when single-celled organisms evolved into multicellular organisms. Both theory and empirical data suggest that extreme conditions are required for major transitions to occur. We suggest that major transitions are likely to be the route to complexity on other planets, and that we should expect them to have been favoured by similarly restrictive conditions. Thus, we can make specific predictions about the biological makeup of complex aliens.

Cambridge University Press

Shouldn’t the abstract give us some idea of what those “specific predictions” are? Luckily, this is an open access article. There are some fun passages about why my hands are willing to help my testicals reproduce, rather than trying to reproduce themselves. This is because “their interests are aligned”, and my testicles have (or once had, at the risk of providing way too much information to the reader…) the potential to produce more hands at some point. Like a termite colony, I have gone through a transition to a complex organism, and my various parts are not out for themselves but are working together in a harmonious whole. (That’s the theory, although I’m not sure those testicles were aligned with my brain during my teenage years…)

So there might be simple alien life out there, in the form of single-celled viruses, fungi, bacteria, algae, or whatever. What we are really interested in is complex alien life, which would consist of “a nested hierarchy of entities, with the conditions required to eliminate conflict at each of those levels”. They could have complex individual bodies along the lines of ours, or some kind of creepy colonies made up of simpler organisms, more like ants or termites but with more tentacles. There are some pictures in the paper, have a look.

Universities have astrobiology departments, and it seems like a fun thing to study. You get to learn about biology and astronomy, combine theory and observation.

tipping points

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A new article from Proceedings of the National Academy of Sciences goes through eight climate change tipping points that have studied, and tries to assign an economic impact to each. I’ll list them here in order of highest to lowest impact according to this study (see Table 2). They use the change in social cost of carbon as their key metric.

Two tipping points have major potential impacts and represent over 80% of the total risk from the eight, according to this study:

  • ocean methane hydrates
  • permafrost carbon feedback

Four tipping points have relatively modest expected impacts, at least modest compared to the truly existential threats represented by the top two:

  • West Antarctic Ice Sheet
  • Greenland Ice Sheet disintegration
  • Indian Summer Monsoon
  • Amazon dieback

Finally, two actually have small positive impacts on the (human) economy according to these authors:

  • Atlantic Meridional Overturning Circulation slowdown (AMOC)
  • Arctic sea ice / Surface Albedo Feedback

They don’t include “nonmarket effects”, so if you just feel that the death of the Amazon forest is profoundly sad, that is not reflected here. The authors are explicit about this so I guess it is okay.

These results are mismatched with my impressions, which are most likely driven by the amount of media coverage given to tipping points. I have probably read the most about ice sheets, the AMOC, and the Amazon, and these somewhat surprisingly do not make the top of the list. I feel like I have some basic grasp of the scientific concepts on each of these other than the methane hydrates. I understand why releasing massive amounts of methane would raise temperatures. I just don’t yet understand the feedback loop that would cause it to happen, whereas with the permafrost thawing it is pretty clear. Are the methane hydrates just frozen and expected to melt? I suppose in that case they are very similar to methane under the permafrost, with the difference being land and water. So the release of vast amounts of trapped methane is by far the biggest impact identified by this paper. For the most part though, the solutions to address any of these tipping points are going to be the same – drastic greenhouse gas emissions reductions and/or drastic geoengineering. Nothing else is going to reduce the amount of heat and solar energy melting ice, thawing permafrost and undersea frozen methane hydrates, and affecting ocean currents across vast chunks of the planet.

early warning of Gulf Stream collapse?

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There has been plenty of hypothesizing that global warming could cause destabilization of key ocean currents that have determined the character of the world’s regional climates over the last few millennia or so, i.e. human history. This new paper is the first I am aware of (but I am not even close to an expert on this subject or oceanography more generally) to find empirical evidence that the the AMOC current (which I believe includes the Gulf Stream) could be nearing a tipping point.

Observation-based early-warning signals for a collapse of the Atlantic Meridional Overturning Circulation

The Atlantic Meridional Overturning Circulation (AMOC), a major ocean current system transporting warm surface waters toward the northern Atlantic, has been suggested to exhibit two distinct modes of operation. A collapse from the currently attained strong to the weak mode would have severe impacts on the global climate system and further multi-stable Earth system components. Observations and recently suggested fingerprints of AMOC variability indicate a gradual weakening during the last decades, but estimates of the critical transition point remain uncertain. Here, a robust and general early-warning indicator for forthcoming critical transitions is introduced. Significant early-warning signals are found in eight independent AMOC indices, based on observational sea-surface temperature and salinity data from across the Atlantic Ocean basin. These results reveal spatially consistent empirical evidence that, in the course of the last century, the AMOC may have evolved from relatively stable conditions to a point close to a critical transition.

Nature Climate Change

This would seem to have major consequences to (1) where and how much food we can grow in the world, and (2) the location of our actual physical coastlines and the coastal cities that house much of the world’s human population. Adjusting to gradual long-term changes in these things will be a challenge. A sudden, major shift might be something our civilization can’t adjust to. The consequences are unimaginably dire. The risk is unknown but this study suggests it is real. Logic and risk management principles suggest that we need to be cautious here and actually do what we can to avoid this. Let’s hope “a point close to a critical transition” is not really all that close in human terms, and we have time for our civilization, with its flawed geopolitical and economic systems, to come to its senses.