January Thaw or Global Warming?

The late spring-like weather Raleigh has been experiencing lately – with daytime temperatures in the 70s, nights in the 50s, and forsythia and redbud in bloom – will soon come to a chilly end. Friday night’s temperature is expected to plummet to around 30 degrees, with daytime highs over the next several days reaching only the 40s and 50s, according to the National Weather Service (NWS).

But this month could still break the record for the warmest January on record, previously set in 1950. And this unusually warm January follows a December in which average temperatures in the Raleigh-Durham area averaged .5 degrees above normal, begging the question: Is the recent spate of warm weather just an ordinary January thaw or local evidence of global warming?

Climatologist Ryan Boyles with the State Climate Office (SCO) at N.C. State University cautiously comes down on the side of the former.

“We’ve seen patterns like this in the past,” he says, citing the first month of 1950 and also 1931. “It isn’t extreme – just unusual.”

Not that Boyles disputes the reality of global warming, mind you: He acknowledges there’s a consensus among scientists that climate change is taking place, and that humans are a driving force. “But to what degree and by what actions is still up in the air,” he says. “What percentage is due to pollution? To deforestation? To increased urbanization?”

It’s also unclear exactly how planet-wide changes are manifesting locally. However, Boyles has found evidence indicating that North Carolina’s climate may be heating up. In a study titled “Analysis of Climate Trends in North Carolina (1948-1998)” conducted with N.C. State Professor Sethu Raman that appeared in the journal Environmental International in 2003, he found that the state’s warm season has become longer, while the difference between maximum and minimum temperatures is decreasing.

But new evidence suggests that analysis may have been flawed, Boyles says. That’s because it relied on data from a nationwide network of volunteer temperature takers known as “cooperative observers.” The problem with their data is that sometimes their sensors get moved, or the area where they’re placed changes due to development. That results in a less-than-accurate picture of temperatures over time.

“We still don’t have the kind of data we need to detect long-term patterns,” Boyles laments.

That could soon change, though, thanks to initiatives by the federal government as well as Boyles’ office. The National Oceanic and Atmospheric Administration is currently developing the U.S. Climate Reference Network (CRN), which would consist of about 110 monitoring stations nationwide, with headquarters at the National Climatic Data Center in Asheville, N.C. The CRN is now operating in 28 states.

“The CRN will give America a first-class observing network for the next 50 to 100 years that will serve as a benchmark for climate monitoring,” says Gregory Withee, assistant administrator for NOAA’s Satellite and Information Service.

In addition, the SCO is asking North Carolina lawmakers to allocate $500,000 in the next budget to establish weather stations in all 100 counties across the state. Currently the SCO has gauges in only 27 counties, with NWS monitors bringing that total up to 50. The proposal will be considered as part of the broader University of North Carolina appropriations package.

“We’re in a race to get the best science we can to take appropriate action,” Boyles says.