Whither Wi-Fi in Warm Weather?

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Caroline Spelman. PHOTO: Reuters/Ueslei Marcelino One would think from reports today that the UK's secretary of state for the environment and rural affairs, MP Caroline Spelman, had lost her bleeding mind. Spelman has been widely quoted about a new report from her agency, Defra, about the threat to infrastructure from global climate change. It covers the extremes of temperature and the routine occurrence of heat above a normal range for the UK, and more storms and severe weather that could ravage Great Britain. The report is an analysis on what changes need be made to keep bridges from buckling in heat or cracking in cold, and nuclear and fossil-fuel plants from suffering damage from previously unthinkable conditions, as well as quotidian issues like floods polluting water supplies and spreading sewage. It's a ripping read, and, please recall, originates from the Tories, the majority conservative part of a coalition government that completely acknowledges the reality of a range of risk potential from climate change. The Conservatives are no Republicans, no matter what else you may say about them. Nonetheless the report's broader issues were overlooked because of a focus on an exceedingly tiny statement buried in it that Spelman highlighted in a speech unveiling the work. Her prepared remarks have her saying:

Our economy is built on effective transport and communications networks and reliable energy and water supplies. But the economy cannot grow if there are repeated power failures, or goods cannot be transported because roads are flooded and railways have buckled, or if intense rainfall or high temperatures disrupt Wi-Fi signals.

The Daily Telegraph paraphrased her as saying in her speech, "The signal from wi-fi cannot travel as far when temperatures increase. Heavy downfalls of rain also affect the ability of the device to capture a signal." The Guardian is more sensible, summarizing her statement as "higher temperatures can reduce the range of wireless communications, rainstorms can impact the reliability of the signal, and drier summers and wetter winters may cause greater subsidence, damaging masts and underground cables." I was puzzled about this, and consulting the report helped a little. First off, the agency isn't talking about Wi-Fi in particular. As is typical, Wi-Fi is used incorrectly as a catchall phrase when "wireless communications" is meant. The report itself says "wireless," and the focus is on large-scale cellular infrastructure using towers (or "masts" as they're called in the UK). Second, the issue of weather affecting signals seems to be tremendously overemphasized in the cabinet secretary's remarks and, naturally, in the coverage. Remember the terrible study and subsequent reporting that alleged Wi-Fi was killing trees all over Europe? So Wi-Fi plus climate change equals headlines. Extreme heat and heavy precipitation may have some affect on signal propagation, but it's likely to be rather small according to a number of geeks I consulted on the topic. The report asserts, "Location/density of wireless masts may become sub-optimal as wireless transmission is dependent on temperature," but I can't find any citations to support that. Rather, the greater risk appears to be from continuously high temperatures causing tower equipment to function more poorly, reducing signal strength, or to be damaged by the heat. Extreme weather could knock out communications by cutting power and backhaul to poles and towers, or toppling them. That's all quite reasonable, and could result in revised standards for how this sort of equipment is deployed, and potentially regulators could change certification standards for telecom gear based on the anticipation of prolonged extreme temperatures. So MP Spelman hasn't gone crazy. But she might get additional consultation before sounding like part of the tin-hat brigade.