Earlier and earlier high-Arctic spring replaced by ‘extreme year-to-year variation’, say researchers

July 30, 2023 by oldbrew

This observation doesn’t correlate with monotonic CO2 rise data. Apparently we’re left looking at ‘tremendous natural climate variability’, which doesn’t sound much like the claims and expectations of prevalent IPCC-type theories. The researchers say ‘temperature increases have stalled’, and ‘the previously observed trend has disappeared completely’. Little wonder then that some Arctic alarmists have been less shrill in recent years — their trend melted away.

– – –
About 15 years ago, researchers reported that the timing of spring in high-Arctic Greenland had advanced at some of the fastest rates of change ever seen anywhere in the world.

But, according to new evidence, that earlier pattern has since been completely erased.

Instead of coming earlier and earlier, it seems the timing of Arctic spring is now driven by tremendous climate variability with drastic differences from one year to the next.

“As scientists we are obliged to revisit previous work to see whether the knowledge obtained at that time still holds,” says Niels Martin Schmidt of Aarhus University in Denmark.

“We looked at previously reported extreme rates of phenological advancements in the Arctic and found that directional advancement is no longer the prevailing pattern. Actually, the previously observed trend has disappeared completely and has been replaced by extreme year-to-year variation in the onset of spring.”

Global changes in climate are expected to take place faster in the Arctic than in places at lower latitudes. To follow those trends, researchers at Zackenberg in Northeast Greenland launched an ecosystem-wide monitoring program in 1996.

Among a suite of ecosystem variables, the program also tracks the timing of spring based on flowering plants, arthropod emergence, and bird nesting.

When the first 10 years of data were analyzed for 1996-2005, the findings showed a clear pattern of advancement across plants and animals included in the study. For instance, they saw some arthropods emerging up to 4 weeks earlier.

In the new study, Schmidt and his colleagues wanted to see how these trends look now that they have 15 additional years of data available.

After analyzing the phenological data from 1996-2020, they report little evidence of directional change in the timing of events even as climate change continues. The researchers attribute this shift to a high degree of climate variability from year to year.

“That the extreme rates of phenological advancement we reported back in 2007 would not have continued unabated was not surprising to us,” Schmidt said. “However, that we see such a consistent shift from directional to extreme variability across so many different organisms and that the entire ecosystem now seems driven by variation in climatic conditions, was surprising.”

Schmidt says that the previous pattern showed steadily rising temperatures and declining snow cover. Now, what they see is a lot messier. Temperature increases have stalled while snow cover fluctuates dramatically from year to year.

“Some years have almost no snow in spring, whereas others have snow on the ground way into the summer season,” he says.

“This leaves us with a generally warmer but much more unpredictable spring climate — and this is where the second contributor to the observed phenological shift kicks in. Some species appear unable to take advantage of the warmer conditions in spring and appear to have reached the limits of their phenological plasticity.”