‘Like Background Noise’: Greenhouse-gas Warming Boosts Shorter-term Weather Cycles

Jan 13, 2017

A record-warm year in the Arctic, partly due to climate change …


The persistently warm temperatures recorded throughout Alaska and the Arctic last year raises a question climate scientists are hearing more and more these days: that is, does that extraordinary warmth prove climate change is happening?

“If one year is a record and the other year is not, it doesn’t mean that global warming is happening one year and it’s not happening the next year,” says Anchorage climatologist Brian Brettschneider. If that were the case, he says it’s unlikely climate change as it’s presently understood would be happening.

An analysis by NOAA's National Centers for Environmental Information concludes 2016 was by far Alaska's warmest year, based on records kept since 1925. Every climate region in the state recorded its warmest year, except an Southeastern Panhandle area around Haines and Skagway.
Credit NOAA NCEI

But he says 2016 was the third consecutive year of above-average temperatures in Alaska, and that numerous high-temperature records were set around the state last year. All in the context of a decades-long trend of steadily rising temperatures.

“It’s like background noise – it’s always there,” he said. “And so the weather, day-to-day, kind of happens on top of that background. But that background is certainly getting warmer.”

Rick Thoman is the climate science and services manager at the Fairbanks National Weather Service office. And like all scientists, he’s careful to respond to the question in a probabilistic way that reflects what’s been learned through analysis of trends or what appear to be trends that are revealed through ever-improving data collection.

“These extremely warm events, these rare events – they become much more likely in a warming world,” Thoman said.

Anchorage climatologist Brian Brettschneider, left, and Rick Thoman, climate science and services manager at the Fairbanks National Weather Service office.
Credit KUAC file photos

The steady uptick in temperatures in Alaska and Arcticwide year over year and other such indicators as rising sea-surface temperatures and decreasing sea-ice cover all are consistent with what would occur as carbon dioxide and other greenhouse gases accumulate in the atmosphere. And unlike other warming-related phenomena, atmospheric greenhouse-gas buildup can and has been measured and confirmed.

“The kinds of temperatures that we’ve seen are extremely unlikely in a cooler world, but become more likely as greenhouse-gas concentrations increase,” Thoman said.

Climate change is of course a theory, but as Brettschneider says the physics of what happens when greenhouse gases accumulate is well-established and consistent with the warming that’s under way.