Rising Global Temperatures Could Affect Military Sensors, Comms Systems.

• Author: Eckert, Cambrie

ARLINGTON, Virginia--Climate change isn't just contributing to unprecedented flooding in New England and record temperatures experienced around the world this summer, it could also degrade critical defense technologies, according to the findings of a research team.

Scientists at John Hopkins Applied Physics Laboratory in Laurel, Maryland, studied the effects of climate change on radio wave propagation, including how rising temperatures can degrade other defense technologies across various marine climates.

The changes could be significant enough to affect next-generation communication systems, navigation and surveillance radars, Jonathan Gehman, lead researcher and applied physicist at the lab, said in an interview.

The team discovered that higher temperatures and increased humidity would likely affect the way radio waves travel, degrading certain infrared bands, like X-band, by 10 to 20 percent. This means engineers might need to consider the environment as an "evolving design factor" when outlining future defense technologies and systems, he said.

"Today, when you're designing these systems, one of the choices you often have to make is between S- and X-band, which are around three and 10 gigahertz, respectively. The tradeoff is that with S-band, you can see farther through the atmosphere, but with X-band and other high-frequency bands, you get better resolution, more bandwidth and a less crowded spectrum," he said in a release.

Global temperatures will likely rise 2 to 4 degrees Celsius higher than current levels in the next 50 to 100 years if carbon emissions continue to rise, the APL study stated.

"What we found was that, over the next 50 years, in the severe scenario, differentiation is likely to become more pronounced. The longer-range advantage of S-band will improve, and X-band and higher frequencies will degrade as a result of increasing moisture in the atmosphere,"...