The Earth has humans, so why don’t our climate models?

November 23, 2020 by Caroline Reed

Over the past few decades, climate researchers have improved our understanding of global warming scenarios by increasing the complexity and precision of climate. These large models, using lots of physics and chemistry, inform projections on related to anthropogenic emissions and the carbon cycle. Often these models also have some integration with economic models that help researchers understand how policy solutions might change rational investment decisions.

However, many of the most referenced “integrated assessment models” have failed to look at a key driver: human behavior.

In a recent paper from the journal Climatic Change, Climate Interactive’s Dr. Travis Franck and co-authors unpack this omission, and how necessary it is for us to include human behavior in climate models going forward. This paper, ‘The Earth has humans, so why don’t our climate models?’ contends that both social and behavioral models should be coupled in parallel with our physical climate models. Franck et al argue that this component is absolutely necessary for us reduce uncertainty and improve our understanding of our future climate system.

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With current models, we are able to see only half of the picture – analyzing how we emit GHG’s, alter our environment and carbon cycle, and the effect of other interventions which potentially mitigate and/or exacerbate the current climate crisis. While many models stop there, this paper illustrates how many of these actions have significant feedbacks which affect our climate system and ultimately result in regional climate impacts. These climate impacts – such as agricultural yield, weather patterns, and climate-borne disease – can have robust implications for the future decisions people make relevant to emissions behavior and mitigation techniques, at both the societal and individual scale. When climate models omit such feedbacks, it obscures half of the picture. The uncertainty of human behavior and societal decisions can be the same order of magnitude as science-based uncertainty, when considering future climate projections.

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Beyond this, Franck et al emphasize that when developing social-climate models, we need to consider a wide variety of social/behavioral models and underlying anomalies. Human behavior, unlike some geochemical processes, is extremely unpredictable in nature. Due to this, it’s important to also consider the diversity of social systems across the world – and how things like government, culture, wealth distribution, and other elements can play into decisions to mitigate global warming. Similarly, it’s important to look at how regional differences in climate vulnerability may influence how certain societal groups might choose to act on climate change.

Click here to read the full paper