The elephant, the blind, and the intersectoral intercomparison of climate impacts
- Hans Joachim Schellnhubera,b,
- Katja Frielera,1, and
- Pavel Kabatc
- aPotsdam Institute for Climate Impact Research, 14412 Potsdam, Germany;
- bSanta Fe Institute, Santa Fe, NM 87501; and
- cInternational Institute for Applied Systems Analysis, 2361 Laxenburg, Austria
It was six men of Indostan
To learning much inclined,
Who went to see the Elephant
(Though all of them were blind).
John Godfrey Saxe, “The Blind Men and the Elephant”
When decision makers discuss anthropogenic climate change, they often ignore the mighty elephant in the room, namely the question of what global warming really means on the ground. By all accounts, the impacts on our physical environment and society would be starkly different if our planet warmed by “just” 2 °C (1, 2), by a “dangerous” 4 °C (3), or by a “mind-boggling” 6–8 °C (4). However, the pictures of those sweltering worlds that are emerging from scientific research are still regrettably vague, blurred, and fragmentary (see, for example, refs. 5⇓–7). The main reason for this vagueness is as obvious as it is tantalizing: the sheer diversity and complexity of potential climate-change effects on the existing multitude of regions, sectors, and cultures make the swift advancement of robust knowledge in this field extremely challenging.
What do we know of the whole problem, when we only have access to information about its parts? (Drawing from www.getwords.com, with kind permission of John Robertson.)
Paradoxically, but entirely rational from the individual researcher’s point of view, the scientific community tends to skip over the messy and multifaceted issue of impacts to focus on better-defined lines of investigation, such as the relationship between greenhouse gas emissions and global mean surface-temperature rise, or the economic costs of limiting warming to specific levels. This focus has enabled the respective communities of scholars to make impressive quantitative progress in the last two decades and to attain a high degree of coordination, as evidenced by important model intercomparison initiatives. More precisely, we are now seeing the results of the fifth phase of the Coupled Model Intercomparison Project (8), representing the backbone of …
↵1To whom correspondence should be addressed. E-mail: katja.frieler{at}pik-potsdam.de.
