The First Climate Model Turns 50, And Predicted Global Warming Almost Perfectly

[JHan]

We use computer models to analyze financial data, traffic patterns, weather systems etc to come to reliable predictions about the future. They're not perfect - they can't be because we don't live in a deterministic universe - but improvements have made these models more reliable over time. In the 60's, Manabe and Wetherald created an atmospheric model, using data gathered roughly a hundred years before, that continues to be accurate - an incredible achievement considering the computing power available to them at the time.

Modeling the Earth's climate is one of the most daunting, complicated tasks out there. If only we were more like the Moon, things would be easy. The Moon has no atmosphere, no oceans, no icecaps, no seasons, and no complicated flora and fauna to get in the way of simple radiative physics. No wonder it's so challenging to model! In fact, if you google "climate models wrong", eight of the first ten results showcase failure. But headlines are never as reliable as going to the scientific source itself, and the ultimate source, in this case, is the first accurate climate model ever: by Syukuro Manabe and Richard T. Wetherald. 50 years after their groundbreaking 1967 paper, the science can be robustly evaluated, and they got almost everything exactly right.

*snip*

The big advance of Manabe and Wetherald's work was to model not just the feedbacks but the interrelationships between the different components that contribute to the Earth's temperature. As the atmospheric contents change, so do both the absolute and relative humidity, which impacts cloud cover, water vapor content and cycling/convection of the atmosphere. What they found is that if you start with a stable initial state -- roughly what Earth experienced for thousands of years prior to the start of the industrial revolution -- you can tinker with one component (like CO2) and model how everything else evolves.

https://www.forbes.com/sites/startswithabang/2017/03/15/the-first-climate-model-turns-50-and-predicted-global-warming-almost-perfectly/#1dd774f96614

[Loki Liesmith]

1. Even if we lived in a deterministic universe the models couldn't be perfect