Freezer failure damages Arctic ice cores

CANADA: A malfunction in a refrigeration system at the University of Alberta has led to partial melting of ice core samples used in investigations into climate change.

The breakdown occurred at the University’s Canadian Ice Core Archive (CICA), which holds more than 80,000 years of evidence of changes to climate. It is said to have affected 12.8%, or 180m, of the 1,409m collection

The collection contains 12 ice cores, drilled from five different locations, and represents the world’s largest collection of ice core samples from the Canadian Arctic. Some were collected as far back as the late 1970s and as recently as the mid-2000s and have been analysed in some detail by scientists.

The ice cores were held in two walk-in freezers in the University’s South Academic Building – a storage unit chilled to -37ºC and an adjacent working unit cooled to -25ºC. The ice cores had only been transferred to the facility on March 24 from the Geological Survey of Canada’s Ice Core Research Laboratory in Ottawa.

Both freezers were commissioned in October and operated for over five months while holding 40  five-gallon buckets of ice to simulate the cores. Both CICA freezer units were said to be functioning properly at noon on Friday, March 31.

Late in the afternoon of Sunday, April 2, the University’s Protective Services and Edmonton Fire Service responded to a high-heat alarm in the facility. Investigators found the temperature in the storage freezer had reached 40ºC, resulting in the damage to the ice core samples.

All affected ice core samples were immediately moved into the working freezer, which was functioning properly and where the majority of the collection was being stored.

An investigation into the breakdown found that the refrigeration chillers had shut down due to high head pressure conditions. Compounding matters, the system monitoring the freezer temperatures failed due to a database corruption. The freezer’s computer system was said to have been sending out alarm signals that the temperature was rising, but those signals never made it to the university’s service provider or the on-campus control centre.

Refrigeration technicians are now said to be monitoring the freezers through twice-daily checks and a second monitoring controller is now issuing real-time messaging updates every eight hours.

Over the next few weeks, a second, independent path of alarming will be installed. The refrigeration system will also be modified to improve performance during failures, such as shutting down the evaporators in the event of a condenser failure. The refrigerated container the university purchased to transport the core collection from Ottawa to Edmonton is also available as a backup.

“Careful thought and attention went into planning every design detail, from the cross-country transport to the facility itself, and we all thought there were no weaknesses,” said university glaciologist Martin Sharp. “An incident of this magnitude is a major disappointment given the investment in the facility and the cost and challenge of replacing the lost samples. When you lose part of an ice core, you lose part of the record of past climates, past environments—an archive of the history of our atmosphere. You just don’t have easy access to information about those past time periods.”