Since 1970, glaciers around the world have been melting, weakening, collapsing and disappearing at a rate never seen before, mainly due to global warming that has unbalanced the ratio of fresh snow to melting ice.
The consequences of these phenomena are floods, droughts, threatened water supplies, and weakened economies that also contribute to the catastrophic effects of climate change.
So many lives depend on these large ice shelves for drinking water, agriculture, hydropower, and tourism that it is essential to foresee and plan accurately for what will happen to them in the future.
Traditionally, glaciologists track the movement of glaciers using markers such as rods, photographs, and historical paintings to compare changes in ice over time. Indirect markers, such as crashed aircraft, can also identify glacier movement.
There is now another, more accurate method that can help glaciologists model glacier behaviour more accurately and, in turn, predict the future of glaciers. This can help decision-makers make planning decisions in the face of glacier retreat or total disappearance.
Some 40 kilometres south of Bern in Switzerland, the Spiez Laboratory has developed a nuclear technique based on the ice footprint of the nuclear weapons tests carried out between 1950 and 1960 that generated and emitted into the atmosphere artificial radionuclides that were deposited in the surface layers of glaciers around the world.
Since the dates of these tests are known, by identifying the maximum concentrations of these radionuclides and their dispersion patterns due to ice flow, it is possible to define the chronology of the ice sheets.
This technique was already used for the measurement of radionuclides in soils and other solid materials, and for the first time, it has been applied to water, ice, and snow.
It involves taking surface ice samples from each glacier, each up to one kilogram, which is sufficient to detect low levels of radionuclides. These are then melted and radiochemical methods are applied to extract and purify uranium and plutonium isotopes, which are analysed with a highly sensitive instrument called a multi-collector induction coupled plasma mass spectrometer (MC-ICP-MS).
Other nuclear techniques such as high-resolution gamma spectrometry, which detects the presence of caesium, or liquid scintillation counting, which detects the presence of tritium, are also applied.
The data obtained can be used to refine and refine glacier flow models, to get a better idea of the rate at which glaciers melt, to predict their future and to calibrate ice flow models for greater accuracy.
The Spiez Laboratory is a centre of excellence with a track record of outstanding analytical competence, with extensive experience in sampling and field measurements of all types of pollutants, in particular radionuclides, and is part of the International Atomic Energy Agency (IAEA) Analytical Laboratories Network for the Measurement of Environmental Radioactivity (ALMERA).
