Did climate change cause that?

In 2013 Typhoon Haiyan, one of the strongest tropical cyclones ever recorded, swept through Southeast Asia killing over 6,000 people, leaving tens of thousands more homeless, and causing billions of dollars' worth of damage. Four days later at the UN Climate Change Conference in Warsaw, the chief Filipino delegate, Yeb Sano, made an impassioned plea for action on climate change:

Mr President, I speak for my delegation, but I speak for the countless people who will no longer be able to speak for themselves after perishing from the storm... We can take drastic action now to ensure that we prevent a future where super typhoons become a way of life. (ABC News 2013)

If Haiyan and other extreme weather events such as heat waves, droughts, or wildfires are caused by climate change, then this would provide us with compelling and immediate motivation to mitigate our effects on the climate. However, the message from climate scientists regarding the causal link between climate change and individual extreme weather events is somewhat confusing (see Chapter 10, Experts in the Climate Change Debate). On the one hand, they tell us that many types of extreme weather event are likely to occur more often as a result of climate change, but on the other, they are reluctant to draw direct links between climate change and particular events. Indeed (until recently, at least) it has been the orthodoxy among climate scientists that despite having good reason to believe that climate change increases the probability of certain extreme events, it is impossible to attribute any single weather event, no matter how extreme, to human-induced climate change (see for example, Karoly 2009: 35; Rahmstorf et al. 2005; Sobel in Campbell 2013: Stott, Stone, and Allen 2004: 610). This attitude is nicely summarized in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), which states that "While individual extreme events cannot be attributed to external influences, a change in the probability of such events might be attributable to external influences" (Hegerl et al. 2007: sec. 9.4.3.3).

This reluctance to draw causal conclusions has political consequences. The UK's former environment secretary, Owen Paterson, for example, has refused to endorse claims by his prime minister, David Cameron, that severe storms which afflicted the UK in January 2014 were linked to climate change. Critics have charged that Paterson's refusal to acknowledge such links has led to under-preparation for severe floods (Johnston 2014; Swinford 2014). In Australia, after devastating and unseasonable wildfires in October 2013, the prime minister, Tony Abbott, dismissed any suggestion of a link between these fires and climate change as ''complete hogwash'' (Bolt 2013). Although many criticized Abbott for this claim, these criticisms focused on the link between climate change and wildfires in general. No prominent climate scientist seemed willing to contradict Abbott by drawing a direct link between climate change and those particular fires. This lack of direct contradiction made it easier for Abbott to push ahead with plans to water down legislation for action on climate change.

I believe that there is some confusion in this debate as a result of insufficient attention being paid to the concepts of "causation" at play. In this chapter I will be turning a philosophical eye on the issue, asking what concept (or concepts) of causation are being employed by scientists and asking which concept or causation is most appropriate. I will show that scientists, politicians, and journalists have made a number of mistakes in their thinking about the causal links between individual events and climate change and will also argue that the confusion about how to think about causation here has led scientists to be more hesitant than they should be when it comes to attributing individual extreme events to climate change.