Things are shaping up differently in tundra areas of Alaska, Russia and Canada.
That is, because ice and Arctic permafrost are rapidly melting there, the shape of land and tundra is altering in very specific ways in the far north of those areas.
Something called ice-wedge degradation is behind it all, says a new study by 19 researchers analyzing data provided by the Southwest Research Institute (SwRI). The researchers also found that rapid melting is present not just in certain areas of the northern reaches, but is widespread in the Arctic.
The study looked at a time series and analyses of change detection in high-resolution imagery from a number of Arctic sites. The point was to better understand what happens on the surface when ice deep underground becomes degraded. It looked at changes in hydrology (water systems) and topography.
"The analysis clearly shows dramatic changes to this landscape, especially during relatively short periods in unusually warm summers in recent years," noted Marius Necsoiu at SwRI's Geosciences and Engineering Division.
If things continue in the current way, draining and subsidence will occur in a widespread fashion. This will have long-term effects on wildlife and plants throughout the Arctic.
"It's really the tipping point for the hydrology," said Anna Liljedahl at the Water and Environmental Research Center at the University of Alaska Fairbanks (UAF).
Believe it or not, at this point, Arctic tundra's landscape is uniquely made up of polygon shapes connected to one another. They are each 15 to 30 meters across. Their shape is formed by sizable frozen ice wedges down in the permafrost, meters deep. These wedges formed as water seeped into cracks in permafrost, and this process took place over hundreds or thousands of years.
The shape of all this affects how drainage, the distribution of snow and general dryness or wetness occur.
In the study, Necsoiu looked at a range of historical aerial photos and satellite pictures from the years 1948 to 1990, comparing those with images from 2005 and 2012. Field observations also went into the mix.
All in all, analyses demonstrated that the landscape now has deep troughs formed as the ice-wedge tops melted. There has also been a decline in lichen, moss and other native plants.
"We were not expecting to see these dramatic changes," said Vladimir Romanovsky, a UAF geophysics professor who participated in the study at a site in Canada. "We could see some other places where ice wedges were melting, but they were all related to surface disturbances, or it happened a long time ago. Whatever is happening, it's something new for at least the last 60 years in the Arctic."
The findings were recently published in the journal Nature Geoscience.
Follow Catherine Arnold on Twitter at @TreesWhales.
