Tuesday, October 30, 2012

Global Warming Systemically Caused Hurricane Sandy

Yes, global warming systemically caused Hurricane Sandy -- and the Midwest droughts and the fires in Colorado and Texas, as well as other extreme weather disasters around the world. Let's say it out loud, it was causation, systemic causation.

Systemic causation is familiar. Smoking is a systemic cause of lung cancer. HIV is a systemic cause of AIDS. Working in coal mines is a systemic cause of black lung disease. Driving while drunk is a systemic cause of auto accidents. Sex without contraception is a systemic cause of unwanted pregnancies.

There is a difference between systemic and direct causation. Punching someone in the nose is direct causation. Throwing a rock through a window is direct causation. Picking up a glass of water and taking a drink is direct causation. Slicing bread is direct causation. Stealing your wallet is direct causation. Any application of force to something or someone that always produces an immediate change to that thing or person is direct causation. When causation is direct, the word cause is unproblematic.

Systemic causation, because it is less obvious, is more important to understand. A systemic cause may be one of a number of multiple causes. It may require some special conditions. It may be indirect, working through a network of more direct causes. It may be probabilistic, occurring with a significantly high probability. It may require a feedback mechanism. In general, causation in ecosystems, biological systems, economic systems, and social systems tends not to be direct, but is no less causal. And because it is not direct causation, it requires all the greater attention if it is to be understood and its negative effects controlled.

Above all, it requires a name: systemic causation.

Global warming systemically caused the huge and ferocious Hurricane Sandy. And consequently, it systemically caused all the loss of life, material damage, and economic loss of Hurricane Sandy. Global warming heated the water of the Gulf and Mexico and the Atlantic Ocean, resulting in greatly increased energy and water vapor in the air above the water. When that happens, extremely energetic and wet storms occur more frequently and ferociously. These systemic effects of global warming came together to produce the ferocity and magnitude of Hurricane Sandy.

The precise details of Hurricane Sandy cannot be predicted in advance, any more than when, or whether, a smoker develops lung cancer, or sex without contraception yields an unwanted pregnancy, or a drunk driver has an accident. But systemic causation is nonetheless causal.

Semantics matters. Because the word cause is commonly taken to mean direct cause, climate scientists, trying to be precise, have too often shied away from attributing causation of a particular hurricane, drought, or fire to global warming. Lacking a concept and language for systemic causation, climate scientists have made the dreadful communicative mistake of retreating to weasel words. Consider this quote from "Perception of climate change," by James Hansen, Makiko Sato, and Reto Ruedy, Published in the Proceedings of the National Academy of Sciences:

...we can state, with a high degree of confidence, that extreme anomalies such as those in Texas and Oklahoma in 2011 and Moscow in 2010 were a consequence of global warming because their likelihood in the absence of global warming was exceedingly small.

The crucial words here are high degree of confidence, anomalies, consequence, likelihood, absence, and exceedingly small. Scientific weasel words! The power of the bald truth, namely causation, is lost.

This no small matter because the fate of the earth is at stake. The science is excellent. The scientists' ability to communicate is lacking. Without the words, the idea cannot even be expressed. And without an understanding of systemic causation, we cannot understand what is hitting us. More