Weatherdem's Weblog

Bridging climate science, citizens, and policy

Extreme Weather, Climate Change, and Public Reporting

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If you have had any exposure to this subject, you probably already have your mind made up about my title. As I’ve gained exposure, via multiple disciplines, I’ve changed my mind. And that allows me to look at climate reporting in new ways.  Take this article and interview for instance. It’s meta-related, masked by the climate’s relationship to extreme weather. There are thousands of examples of conservatives ignoring science when it suits them. Doing so actually has more to do with conservatives operating from their value system. Are there similar examples of others ignoring science when it similarly suits them? I think it would be foolhardy to assume otherwise. Here is what I think about this article.

First, the mask: climate-extreme weather. There is no documented causal relationship between the two. In fact, the number of identified causal relationships between climate change and anything is still relatively small. There is a strong temperature signal. There is a growing ocean acidification signal. The sea level change signal is small but present and growing. How about precipitation? Nothing definitive. How about snowstorms? Nothing definitive.

But those signals are small against much stronger climate signals. Would something like drought or hurricanes or floods or tornadoes exhibit a stronger signal. In a word, no. There simply is not a detectable climate and extreme weather link today. That is not to say a future signal will not exist – there very well might be. But as of today, there is not. What science backs up that claim? The 2008 U.S. Climate Change Science Program’s Synthesis Report for starters (p.42;

When averaged across the entire United States (Figure 2.6), there is no clear tendency for a trend based on the PDSI. Similarly, long-term trends (1925-2003) of hydrologic droughts based on model derived soil moisture and runoff show that droughts have, for the most part, become shorter, less frequent, and cover a smaller portion of the U. S. over the last century (Andreadis and Lettenmaier, 2006).

So as of the early 21st century, U.S. droughts have become less severe, not more. The IPCC’s global analysis on extreme events concurred (p.171):

There is not enough evidence at present to suggest high confidence in observed trends in dryness due to lack of direct observations, some geographical inconsistencies in the trends, and some dependencies of inferred trends on the index choice. There is medium confidence that since the 1950s some regions of the world have experienced more intense and longer droughts (e.g., southern Europe, west Africa) but also opposite trends exist in other regions (e.g., central North America, northwestern Australia).

One big impediment to our extreme event trend ascertainment is our basic inability to monitor events in the first place. But based on the observations made, there is, in the IPCC’s own language, only medium confidence that droughts in some areas of the world are increasing in severity while decreasing in other places. Is climate change increasing extreme events? Not droughts – not yet.

What about storms like Sandy or Katrina (note: the former was a tropical system that changed to an extratropical system at landfall while the latter was a full-fledged hurricane at landfall)? There is at this time no global trend in hurricane frequency or intensity that demonstrates a clear causal relationship to climate change. There are indexes that a few scientists have developed to examine the data in different ways with differing results, but they require fairly complex methodologies to calculate. If I created my own index that demonstrated a relationship between the type of food I ate and climate change, does one cause the other? Certainly not directly. The hurricane-climate change relationship should exhibit a detectable signal in 50 more years or so. Until then, scientists cannot confidently say the data supports such a relationship. Extratropical storms increased in strength a little over the past century, although the locations of increase are limited. Their frequency has not increased.

Quickly, the same thing holds for floods and tornadoes. Datasets are simply too limited in space and time to currently identify a robust relationship.

As I wrote above, there are clear signals that we have already detected. The effects of those signals are mostly well-known, although some surprises are certainly in store for the planet. Extreme weather is not one of those signals. At least, not yet. If people are concerned about the level of inaction taken on climate change to date, it is folly to chase down or exaggerate signals that do not yet exist. If arguments based on signals detected are not enough to propel action, then we need to address their sets of values and how we communicate them. Fear-mongering and purposeful ignorance of science are not adequate substitutes.

Finally, I question the following from the article:

“I quote the climate skeptics or deniers — whatever term you prefer — when they’re relevant. So when I’m doing a piece about the science itself and what the latest scientific findings are, especially if that’s a short piece, I don’t necessarily feel obliged to quote the climate skeptics the same way that if you were doing a story about evolution, a New York Times reporter wouldn’t feel obliged to call up a creationist and ask them what they think. On the other hand, the climate skeptics are politically relevant at this point in American history [in a way that] the creationists are not, for example. So we have a fair chunk of the Congress … that sees political traction right now in questioning climate science or purporting not to believe it, so in a political story or in a longer story, I usually do give some amount of space to the climate skeptics.”

This quote comes from Justin Gillis, who writes about climate change for The New York Times. Does any of the above evidence make it into his interview with NPR? Here is my question: is Mr. Gillis a climate change writer or a politics writer? Scientific climate change writers should focus on the science. If Mr. Gillis wants to be a political climate change writer, he and the NYT owe it to their readers to make that distinction clear. Especially when double standards are applied to a different type of science writing. I would argue that creationists have a considerable amount of political traction right now also. I do not agree with their viewpoint, but if Mr. Gillis and the NYT want to write comparison pieces and not news pieces, I do not see why that effort should stop at climate change.


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