Friday, September 15, 2017

Harvey, Irma And Global Warming: The Facts From Experts Whose Opinions Matter More Than Mine Or Yours

After hurricanes Harvey and Irma, it was hard to miss the multitude of headlines demanding that we pay attention to global warming now. Those who refuse to see this connection are science deniers at best and possibly criminals at worst (some are suggesting politicians who deny or minimize global warming should be arrested). 

But there were other voices as well, voices cautioning that the correlation was not so clear. The more I read, the more I realized how many 'weasel words' permeated the coverage (might, could, likely, probably, many speculate, etc). Even worse, headlines and even conclusions within articles often did not align accurately with the actual facts in the article. 

I figured it was time for some research. I looked for national and international agencies, think tanks, meteorologists and climatologists. I did not try to avoid anything or confirm a particular bias. As far as I know, what I have to offer represents the mainstream or consensus scientific view. I know "consensus" is a dirty word in some circles, but if it's good enough to give force to the global warming argument, it should be good enough to give weight to this topic as well.

These quotes will address the number of hurricanes, their strength and duration as compared with existing data over the history of hurricane activity, and whether or not we should be drawing a connection between the power of the recent hurricanes and global warming. 

I think you will see that while there is minor disagreement, the general consensus is solid: global warming does not get credit for Harvey and Irma (except for perhaps a couple extra inches of rain). These are not climate change deniers saying this. Everyone I read affirms that the globe is warming, and that if trends continue we should eventually see significant impact, even if it might be a while. 

(It's worth noting I have only a few links to comments after 2015, since the study of the storms go on for quite some time after the hurricane seasons are over.) 

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  • Atmos, the University Corporation for Atmospheric Research, is "a nonprofit consortium of more than 100 North American member colleges and universities focused on research and training in the atmospheric and related Earth system sciences. UCAR manages the National Center for Atmospheric Research with sponsorship by the National Science Foundation." In an article entitled “Hurricanes, Typhoons, Cyclones," they state: “On average there are about 70 to 110 named tropical cyclones per year across the world, including about 40 to 60 that reach hurricane strength. This range has held remarkably steady within the last 40 years. Within each basin, the numbers often vary more dramatically than the global average…After dipping to 30-year lows in the early 2010s, global ACE values have begun rising again.  Of all the hurricanes that build over the North Atlantic and Gulf of Mexico each year, only a small fraction make it to the U.S. coastline at hurricane strength. As of early 2013, the nation had not seen a major landfall (Category 3 or stronger) since 1995. However, the total number of hurricanes swirling across the North Atlantic remains unusually high. “ 
  • According to“Historical Global Tropical Cyclone Landfalls”: "While there is continued uncertainty surrounding future changes in climate… current projections of TC frequency or intensity change may not yield an anthropogenic signal in economic loss data for many decades or even centuries… Thus, our quantitative analysis of global hurricane landfalls is consistent with previous research focused on normalized losses associated with hurricanes that have found no trends once data are properly adjusted for societal factors.”
  • In an article about Hurricane Harvey, The Atlantic reports: “Thomas Knutson, a research meteorologist at the NOAA fluid-dynamics laboratory in Princeton, New Jersey, told me that a “trade-off” signal still isn’t strong enough to see in the hurricane data. “We haven’t really detected clear changes in the data in the same way we can detect changes in global mean temperature,” he says. “I just think [30 years] is a rather short record to be inferring [human-caused climate] effects, because you can also have natural modes of variability over a period of several decades.”  
  • It's no secret that increased cyclone activity correlates with increased sea temperatures. The NOAA notes: “Natural variability apparently plays a significant role in hurricane frequency and intensity, and currently appears to play a bigger role than greenhouse warming…. the Atlantic Multidecadal Oscillation, or AMO… is a pattern of sea surface temperature changes between warm and cold phases in the North Atlantic Ocean. The pattern tends to vary on multidecadal time scales, but the limited length of the Atlantic sea surface temperature record prevents scientists from making more definitive statements about the precise nature of the AMO.”
  • Some have  emphasized the role of a natural 20-40 year cycle in ocean temperature (the AMO, for example). Others think the effect is minimal. Christopher Landsea, quoted in an NOAA article, says: "The late nineteenth century was a very busy period… Then from the 1900s until about 1925, it was very quiet. The late 20s to the 60s were very busy. The 1970s to the mid-90s were quiet again, and then from the late 90s onward, it's been generally very busy."
  • "What I think we can say is that the fact that we do have climate change, our atmosphere is warmer, it contains more moisture, it means that when we do have a hurricane, a tropical cyclone like this, then when an event does occur, then you know climate change does very likely increase the associated rainfall. But climate change per se does not cause tropical cyclones," said Clare Nullis Kapp of the World Meteorological Organization. 
  • In an article about a research team's paper published in Nature Geoscience in 2010: "Landsea and Kossin worked with Thomas Knutson, a research meteorologist at NOAA's Geophysical Fluid Dynamics Laboratory, and seven other researchers. Citing roughly 50 sources, most of them published in the previous five years, the authors concluded that it was uncertain whether the recent increase in tropical cyclone activity exceeds what could be expected from natural variability. That's not to say, however, that tropical cyclones have not changed due to human influences, nor that any changes in future tropical cyclones will not be attributable to our warming climate." 

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I'm not that interested in debating climate change. I'm interested in truth, and I am frustrated and a little angry about what happened during and after the recent hurricanes: the click bait headlines, the fear-mongering, the shrill decrying of anyone who dares question the hurricane/global warming correlation, the ridiculous assertion that people who question anything about the global warming narrative are either stupid, evil, criminal, or a combination of all three. 


Have you heard the story about the boy who cried wolf/global warming? Eventually, nobody believed him when the danger was clear and present. This distortion of reality for the sake of an argument will end up simply raising the level of skepticism when there is a real argument to be made. 

Let truth carry its own weight. If you need to lie so people take your claim seriously, maybe you should be building your argument with another claim.

1 comment:

  1. I found it poignant that one commenter on an article basically said that he knew the poster believed in agw, and was therefore dismayed that he would post an article saying that these hurricanes were not a result of them even though they weren't. He believes it, but it dismayed him because it could harm the narrative if the truth is spoken, apparently.

    The Truth matters more than your politics, it's especially hard to see that though if the truth disagrees with your politics