Articles | Volume 7, issue 4
Research article
02 Nov 2016
Research article |  | 02 Nov 2016

A user-friendly earth system model of low complexity: the ESCIMO system dynamics model of global warming towards 2100

Jorgen Randers, Ulrich Golüke, Fred Wenstøp, and Søren Wenstøp

Abstract. We have made a simple system dynamics model, ESCIMO (Earth System Climate Interpretable Model), which runs on a desktop computer in seconds and is able to reproduce the main output from more complex climate models. ESCIMO represents the main causal mechanisms at work in the Earth system and is able to reproduce the broad outline of climate history from 1850 to 2015.

We have run many simulations with ESCIMO to 2100 and beyond. In this paper we present the effects of introducing in 2015 six possible global policy interventions that cost around USD 1000 billion per year – around 1 % of world GDP. We tentatively conclude (a) that these policy interventions can at most reduce the global mean surface temperature – GMST – by up to 0.5 °C in 2050 and up to 1.0 °C in 2100 relative to no intervention. The exception is injection of aerosols into the stratosphere, which can reduce the GMST by more than 1.0 °C in a decade but creates other serious problems. We also conclude (b) that relatively cheap human intervention can keep global warming in this century below +2 °C relative to preindustrial times. Finally, we conclude (c) that run-away warming is unlikely to occur in this century but is likely to occur in the longer run. The ensuing warming is slow, however. In ESCIMO, it takes several hundred years to lift the GMST to +3 °C above preindustrial times through gradual self-reinforcing melting of the permafrost.

We call for research to test whether more complex climate models support our tentative conclusions from ESCIMO.

Editorial note: Please note that the acronym for the software model described in the ESD paper is now recognized to be culturally insensitive and inappropriate. The editors of the journal ESD, the journal owner European Geosciences Union, and the publisher Copernicus Publications foster equality, diversity, and inclusiveness in scientific exchange, and do not condone in any way racism, discrimination, or cultural appropriation. The authors did not intend to insult any ethnic groups by using the acronym for this software model.

Short summary
We describe ESCIMO, a system dynamics simulation model which is designed to make it simple to estimate the effects of possible human interventions to influence the global surface temperature. ESCIMO consists of sectors that track global carbon flows, global energy flows and global albedo change. One conclusion is that human interventions that cost less than 1 % of world GDP are at most able to lower the temperature rise in 2050 by up to 0.5 °C and in 2100 by up to 1.0 °C.
Final-revised paper