Review of Limits to Growth and discussion of climate, ecological and geopolitical risk by Michael Angelo Caci 12/22/23

Limits to Growth An update of the World3 model (see attached links for references), was published in 2023 and revisits the famous 1972 research published as a book titled "Limits to Growth" by a group of scientists and physicists organized by The Club of Rome with lead scientists Dennis and Donatella Meadows. (Link to the publication- https://www.library.dartmouth.edu/digital/digital-collections/limits-growth)

This review begins by quoting the papers introduction followed by short summary paragraphs by Caci synthesizing key research modules from leading scientists.

“1. Introduction

The Limits to Growth (LtG) is the name of a study conducted in the late 1960s for the Club of Rome. A group of researchers at the Massachusetts Institute of Technology developed a computer model that simulated some of the world’s most important material variables, such as population, food production, resource use, and environmental impact. A total of 12 scenarios were presented in 1972 in the first book of the same name (Meadows et al., 1972). The scenarios cover the period from 1900 to 2100. The authors emphasize that the scenarios are not predictions. Rather, they are intended to illustrate the complex interrelationships within a dynamic system based on exponential growth.

The first and probably best known scenario is called the “standard run” or “business as usual” (BAU), which shows an exponential growth dynamic of the system and leads to the overshoot and collapse mode triggered by the depletion of non-renewable resources. The other scenarios describe changes in the parameterization of the model and assumptions about technological and societal developments. In the scenario called business as usual 2 (BAU2), twice as many initial non-renewable resources (NRI) were assumed and recycling technologies were implemented. These changes result in a different trajectory for each variable, but do not change the overshoot and collapse mode. The collapse in this case is caused by excessive pollution (Meadows et al., 1972). The scenario comprehensive technology (CT) assumes a very broad application of technological solutions. Thus, the pollution rate is greatly reduced, crop yields on agricultural land are greatly increased, and resource efficiency is set above all historical values (Herrington, 2021). The basic dynamics in this scenario are different from those mentioned above. The industrial variables as well as the food production still show exponential growth, but the population growth slows down and reaches a plateau from the middle of the analyzed time period. In this scenario, the collapse is postponed to the end of the time period under consideration, but there are some steep downward slopes at the end.

The problems……the arms race, environmental deterioration, the population explosion, and economic stagnation - are often cited as the central, long-term problems of modern man. Many people believe that the future course of human society, perhaps even the survival of human society, depends on the speed and effectiveness with which the world responds to these issues. And yet only a small fraction of the world's population is actively concerned with understanding these problems or seeking their solutions.” (P17)

A graph from the paper showing food production peaking (BAU, or business as usual curve) in mid-2023. Production declines rapidly in 2024 leveling off to levels prior to the advent of ammonia fixing technology in 1913 developed by Fritz Haber and Carl Bosch referred to as the Haber-Bosch process: natural gas is combined with atmospheric nitrogen to create ammonia.

Research support for the Recalibration paper:

Planetary Boundaries and Cascading Tipping Points

The Planetary Boundary model was developed by Johan Rockström’s team at the Potsdam Institute.

These boundaries refer to ranges in areas where any particular system, whether it be planetary Ice, forests, ocean currents, etc. remains within a safe range of stability. When 6 or more of these systems have crossed a safe boundary Earth’s climate systems becomes unstable, rigid and lacking resilience, all signs of a coming tip toward a different climate state: in this case an ice free planet. According to their research, 6 of 9 planetary boundaries have tipped. Rockström’s model emerged from an understanding of cascading tipping points in climate systems.

The main ones:

- Thermohaline circulation (ocean currents)

- Boreal forests and permafrost

- Coral reefs

- Rainforests

- Cryosphere (planetary ice)

Tipping points become likely with average Global Temperatures equal to or in excess of 1.5 °C. In 2023 the average global temperature pierced 1.74°C. More recent climate models suggest risk of cascading tipping points occurs above 1.1°C

Methane:

Methane is a major risk factor in climate stability and of great concern due to its potency as a greenhouse gas.

(https://climate.mit.edu/ask-mit/why-do-we-compare-methane-carbon-dioxide-over-100-year-timeframe-are-we-underrating)

Methane has been shown through paleological and geological research to have released exponentially (explained below) at various times in the Earth’s history during climate termination events- glacial to ice free.

(Exponential functions=doubling pattern. 2x2=4, 4x4=16, 16x16=256, 256x256=65,536, 65536x65536=4,294,967,000,000,000.)

Euan Nisbet is a leading scientist studying global methane emissions and Earth’s climate history of the link between methane release and climatic change. He describes 4 different "Climate Termination Events" in the Earth’s history related to methane emissions. Termination events in climate science refers to abrupt changes in a glacial cycle referring planetary. The Earth is experiencing accelerated ice loss from Arctic, Greenland and Antarctic ice sheets.

https://www.youtube.com/watch?v=kDwxFS0KeQY

Global Temperature Acceleration:

Dr. James Hansen published a letter on 07Dec2023 summarizing global climate change science. He describes two main "forcings"- literally forces driving global temperature increase: GHGs are growing (warming force) while aerosols (air pollution) are declining (cooling force). Aerosol reductions are primarily due to IMO (International Marine Organization) regulations requiring cleaner diesel fuels to bring down the pollution caused by large ocean going marine vessels. The first set of rules were passed in 2015 during a super El Niño and, as Hansen et al show in a recent study “Global warming in the pipeline (https://academic.oup.com/oocc/article/3/1/kgad008/7335889) aerosol reductions are a significant factor increasing the EEI. Dr. Michael Mann, an important climate scientist, disagrees with Hansen’s assessment that warming is accelerating, not that it’s increasing. He claims that if we stop burning fossil fuels, warming will stop. I mention Mann in case you encounter disagreements with Hansen. Both men, and their teams, agree that warming is increasing. They disagree on whether it’s accelerating. Dr. Mann’s position on acceleration is likely incorrect according to a large and growing body research (https://www.youtube.com/watch?v=o5lo6G26d9M).

Hansen points out that the Earth's energy imbalance (EEI- the amount of solar radiation collected by the Earth or reflected back into space) caused by these 2 forcings- aerosols and GHGs- have 2°C global warming baked in unless purposeful actions are taken to reduce the current extraordinary planetary energy imbalance. Measures of the EEI are based on satellites and datasets, and from ocean and land sensors. They show large increasing planetary absorption of solar radiation. 2°C represents a catastrophic boundary. Hansen et al point out this temperature will be reached before the end of this decade without drastic action to reduce the EEI to zero: a balance of incoming and outgoing.

Hansen goes on to write, "in other words, if we wish young people to inherit a planet comparable to the one that existed for the past 10,000 years, it will be necessary to reduce the enormous geoengineering of the planet that our human-made emissions have engendered." (Hansen el al. "A Miracle Will Occur" Is Not Sensible Climate Policy 07 Dec '23, p8")

If the EEI remains positive (above zero) the Earth will continue to warm rapidly. Reducing the EEI would require we stop burning fossil fuels and, just as important, developing impactful GHG extraction methods to bring down their current levels. Thus far no progress has been made while new record levels of GHGs occur in spite of the “Green Revolution”.

Studies of Earth’s climate systems by a number of scientists across a large body of evidentiary datasets on land, ocean and atmosphere indicate key boundaries are being crossed. For example, ice, as it measures albedo (reflectivity), is one. Most of us know that wearing dark colors in cold weather will be much warmer than lighter colors. The Arctic has been warming 4-6X faster than lower latitudes for quite some time. A massive amount of ice has disappeared from this region exposing dark ocean water. Glaciologists, such as Peter Wadhams and Jason Box, have documented unexpected and deeply concerning melt rates and ice loss in the Arctic and Greenland over the past 4 decades. And while the Antarctic lagged the Arctic previously it’s begun catching up. Scientists studying the Antarctic are publishing studies with titles which regularly include phases related to the potential for accelerating change. (link to publication- https://www.nature.com/articles/s41586-023-05876-1)

Limits to Growth, 2024

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