5G networks could set weather forecasting back decades

Many people are looking forward to the faster and more reliable mobile phone service that 5G networks are promising. But meteorologists are warning that those features could come at a cost: accurate weather forecasting.

That's because the U.S. government is auctioning network frequencies at 24GHz for the service, which is very close to the radio frequency emitted by water vapour.

"The value of that water vapour data we take from satellites is that we can really see storms in the genesis stage—and then forecast them into the future to not only see their track, but also their intensity," Jordan Gerth, a research meteorologist at the University of Wisconsin, told Spark host Nora Young.

Gerth and others are warning that the advent of 5G cellular networks could wreak havoc on forecasting.

"There's certain radio frequencies where molecules in the atmosphere actually emit a very faint signal, and that faint signal—in certain radio frequencies—is detectable with weather satellites, and we use that faint signal as an input into complex mathematical models that forecast the weather," he said.

If that frequency is used by cellular phones, it would drown out the water vapour signals, he said.

"It's a bit like a downtown area of a city, getting quite crowded with new buildings and new apartments. We're trying to cram as much capability into a very small part of the radio frequency spectrum... trying to put a very loud signal from the 5G right up against the very soft signal that we need for sensing water vapour—and that's just not a compatibility that's going to work very well," Gerth said, noting that, as things stand now, the 5G signals will be around 1000 times stronger than the signal emitted by water vapour.

Losing that data would set forecasting accuracy back decades, Gerth said. In particular, it would hamper meteorologists' ability to predict accurately when large storms are going to hit urban areas, which is critical in organizing evacuations and other precautions.

Gerth said the issue would affect worldwide forecasting, because weather satellites share information globally.

The U.S. National Ocean and Atmospheric Administration, or NOAA, has asked the U.S. government to reconsider the strength of the allowable signal, he said. "That's really the best way to resolve this, other than asking the 5G community to find a different piece of that radio frequency spectrum to use."