World4 is a predictive model for world population. Population has grown hyper-exponentially in the last millenium, with the doubling time decreasing from 900 years  in 1000 CE to a minimum of ~35 years in 1963 CE. Technology is defined as that which decreases the death rate and/or increases the effective birth rate (i.e. by decreasing infant mortality). Technology grows exponentially, therefore population fits a hyper-exponential (exponent within an exponent). Models for the end of growth are explored using equations that express the ways humans are depleting Earth's biocapacity, the nature of resource depletion, and the relationship between natural resources and human carrying capacity. This simple model, containing just two closed systems, captures the subtle shifts in the population trajectory of the last 50 years. Specifically, hyperexponential growth has given way to subexponential growth. A peak is predicted for the time around 2028.  [Bystroff, C. (2021). Footprints to singularity: A global population model explains late 20th century slow-down and predicts peak within ten years. PloS one, 16(5), e0247214.]

As initially proposed by Pr. William M White of Cornell University:

𝗙𝗿𝗼𝗺 𝗘𝘅𝗰𝗲𝗹 𝘁𝗼 𝗜𝗻𝘀𝗶𝗴𝗵𝘁 𝗠𝗮𝗸𝗲𝗿: 𝗩𝗶𝘀𝘂𝗮𝗹𝗶𝘇𝗶𝗻𝗴 𝗦𝘆𝘀𝘁𝗲𝗺 𝗗𝘆𝗻𝗮𝗺𝗶𝗰𝘀 𝘄𝗶𝘁𝗵 𝗔𝗜

Spreadsheets revolutionized how we work with data - they made computation accessible and practical for everyone. But tables full of numbers often hide the bigger picture: the systemic relationships between variables.

What if you could see your spreadsheet not just as numbers, but as an interactive diagram that reveals 𝗵𝗼𝘄 𝗲𝘃𝗲𝗿𝘆𝘁𝗵𝗶𝗻𝗴 𝗰𝗼𝗻𝗻𝗲𝗰𝘁𝘀?

That’s exactly what this project demonstrates. Using 𝗖𝗵𝗮𝘁𝗚𝗣𝗧 𝟱.𝟮, I transformed a traditional Excel model into a 𝘀𝘁𝗼𝗰𝗸 𝗮𝗻𝗱 𝗳𝗹𝗼𝘄 𝗱𝗶𝗮𝗴𝗿𝗮𝗺 ready for simulation in 𝗜𝗻𝘀𝗶𝗴𝗵𝘁 𝗠𝗮𝗸𝗲𝗿.

Here’s how it worked. I prompted ChatGPT to: 
• 𝘊𝘰𝘯𝘷𝘦𝘳𝘵 𝘵𝘩𝘦 𝘢𝘵𝘵𝘢𝘤𝘩𝘦𝘥 𝘴𝘱𝘳𝘦𝘢𝘥𝘴𝘩𝘦𝘦𝘵 𝘪𝘯𝘵𝘰 𝘢 𝘴𝘵𝘰𝘤𝘬 𝘢𝘯𝘥 𝘧𝘭𝘰𝘸 𝘥𝘪𝘢𝘨𝘳𝘢𝘮 𝘵𝘰 𝘣𝘦 𝘪𝘮𝘱𝘰𝘳𝘵𝘦𝘥 𝘢𝘴 𝘢 𝘑𝘚𝘖𝘕 𝘧𝘪𝘭𝘦 𝘪𝘯𝘵𝘰 𝘐𝘯𝘴𝘪𝘨𝘩𝘵 𝘔𝘢𝘬𝘦𝘳. 𝘗𝘢𝘳𝘢𝘮𝘦𝘵𝘦𝘳𝘴 (𝘔11, 𝘔12, 𝘦𝘵𝘤.) 𝘴𝘩𝘰𝘶𝘭𝘥 𝘣𝘦 𝘢𝘥𝘫𝘶𝘴𝘵𝘢𝘣𝘭𝘦 𝘷𝘪𝘢 𝘴𝘭𝘪𝘥𝘦𝘳𝘴, 𝘵𝘪𝘮𝘦 𝘶𝘯𝘪𝘵 𝘪𝘴 𝘔𝘖𝘕𝘛𝘏𝘚, 𝘢𝘯𝘥 𝘶𝘴𝘦 𝘌𝘶𝘭𝘦𝘳 𝘪𝘯𝘵𝘦𝘨𝘳𝘢𝘵𝘪𝘰𝘯.

After a few refinements in the chat, I imported the generated JSON directly - 𝗻𝗼 𝗺𝗮𝗻𝘂𝗮𝗹 𝘁𝘄𝗲𝗮𝗸𝘀. The resulting diagram is shown here exactly as created by AI. It’s admittedly a bit rough, but intentionally so: it shows the raw potential of AI-assisted modeling.

The best part? The simulation output matched the original spreadsheet values exactly - validated in the "𝘛𝘢𝘣𝘭𝘦 𝘧𝘳𝘰𝘮 𝘐𝘯𝘴𝘪𝘨𝘩𝘵 𝘔𝘢𝘬𝘦𝘳" and "𝘝𝘢𝘭𝘪𝘥𝘢𝘵𝘪𝘰𝘯" tabs.

This isn’t just a technical experiment. It’s a step toward making 𝗦𝘆𝘀𝘁𝗲𝗺 𝗗𝘆𝗻𝗮𝗺𝗶𝗰𝘀 𝗺𝗼𝗿𝗲 𝗶𝗻𝘁𝘂𝗶𝘁𝗶𝘃𝗲 and 𝘀𝗽𝗿𝗲𝗮𝗱𝘀𝗵𝗲𝗲𝘁𝘀 𝗺𝗼𝗿𝗲 𝗶𝗻𝘀𝗶𝗴𝗵𝘁𝗳𝘂𝗹. By visualizing data flows and feedback loops, we can communicate complex models more clearly and make better decisions.

I hope this inspires you to explore similar integrations between spreadsheets, AI, and simulation tools. Have you tried something like this? I’d love to hear about your experiments!

Let’s push how we model, visualize, and communicate systems. If you find this useful, feel free to share and connect.

📝 Full ChatGPT Conversation – See the prompt and AI workflow
https://lnkd.in/14y08o75

📊 Original Google Spreadsheet – View the source data and validation
https://lnkd.in/u5levi1w

📈 Interactive Stock-Flow Model – Explore the diagram in Insight Maker
https://lnkd.in/238swvx0

A Growth and Underinvestment structure is simply an elaborated Limits to Growth structure where the growth inhibitor is part of another Balancing Loop with an external standard and some delay. The real nasty thing about this structure is that the two Balancing Loops form a single Reinforcing Loop which inhibits growth. See also Archetypes.

Video

This model is part of

And? Understanding Relationships & Their Implications.

La situación modelada expresa el crecimiento de las ventas impulsadas por la motivación y productividad, pero es frenada por el tamaño del nicho de mercado.