A New Model of Climate Change for the Anthropocene Epoch

Promo image. National Science Review

Climate change models should do more than just predict dire results from rising carbon dioxide levels. They must help guide political choices that could alter disastrous outcomes, or they do little more than help us calculate insurance rate hikes and make emergency plans.

A paper by an international group of University of Maryland-led scientists, counting no less than 5 members of the National Academy of Sciences to their ranks, argues that current climate models will fail precisely because they focus too much on the science and not enough on sociology.

"The Human System has become strongly dominant within the Earth System"
  1. The paper makes two key observations:
    Current models may address the influence of projected population growth, GDP growth, or other social factors -- but they do not integrate these factors in a coupled, bi-directional feedback loop.
  2. By treating social factors as externalities, climate models reinforce the human tendency to perceive measures taken to control climate change as "costs" rather than as cost effective or good investments.

The solution? Toss the current models, such as the Integrated Assessment Models (IAMs), and create new Earth System Models (ESMs) that can better predict wider factors that can influence climate change.
The concept underlying this recommendation is known as "coupling" - when change in one parameter causes change in other parameters. The IAMs earned the "integrated" in their acronym by including energy and agricultural influences. But they still input factors like population from external reports that may not account for the impact of climate change on population growth.

To see how broader integration is essential, take this example: if we educate women birth rates fall and population growth slows. Education would not be selected as a priority influence in current climate models which do not "couple" social factors with climate outcomes, but could be analyzed more fully in Earth System Models. Perhaps money currently spent subsidizing electric cars would be better spent in educational outreach?

Or the other way around: because education contributes to greater growth in per capita income, the effects of lowering the number of people might be overwhelmed by the vastly higher environmental footprints typical of wealthier populations (the richest 10% of humanity produce over half of greenhouse gas emissions).

In a more critical example, current climate models point to massive reductions in fossil fuel use as a solution. This obvious path forward has consistently failed to gain political traction, though, because it is perceived as "too high a cost" to the global economy. Earth System Models (ESMs) need to show how the use of our air and our rivers as sinks for human outputs also poses "too high a cost" as growth becomes hemmed in by limitations in the earth's ability to process our outputs or supply our needs.

The scientists behind the paper wisely point out that good policy involves more than just perfecting the models, which is hard enough. When it comes to discussing issues such as family planning or displacement of pollution versus growth of developing economies, human rights issues must be considered as well.

It has been officially proposed that we have been living in the Anthropocene epoch since approximately the Industrial Revolution. Whether advocates gain approval for this concept of a new epoch or not, the term is intended convey that we humans are now the most significant influencing factor on the evolution of our planet. It also proves how little we understand that in the end, it will be the earth that influences our evolution.

What remains to be seen: can Earth System Models (ESMs) pierce the denialism and outright apathy about climate change before the Anthropocene turns out to be the shortest epoch?

Read the entire article, Modeling sustainability: population, inequality, consumption, and bidirectional coupling of the Earth and Human Systems, published unlocked in the National Science Review,