It’s the dawn of a new era for Swiss climate science

Arosa, in the Swiss Alps is where ozone measurements began, almost 100 years ago. Now Arosa's Light Climatic Observatory is preparing to move to Davos.

The dominant climate story of the 1980s was the ozone layer. Concerns about the depletion of the ozone layer, a part of the stratosphere between 15 and 35km above the Earth's surface, date back to the 1970s but they took a decade to reach mainstream awareness.

The ozone layer is vital for absorbing the sun's harmful shortwave UV radiation, which causes skin cancer and affects marine ecosystems and agricultural productivity. In the mid-1980s the world became aware of 'holes' in the ozone layer, particularly over the poles - though in reality these are just very thin parts of the layer.

Tuberculosis is the reason that Arosa began to measure ozone levels, 60 years before most people in the world had any idea that they might be important. The bacterial infection is today tackled with immunisation and antibiotics but in the early 20th Century, before the availability of antibiotics, mountain air was thought to have healing properties. Many wealthy people travelled to the Alps to convalesce.

The Arosa spa and tourist office began to fund the LKO in the 1920s, aiming to attract more people by proving the healing power of the local air. By the 1940s, antibiotics were an available and accepted treatment for tuberculosis, so the measurements were no longer necessary - at least not for their original purpose.

However, Friedrich Gotz, the German scientist who founded LKO, managed to keep it funded beyond the 1940s and made a number of significant scientific contributions to atmospheric ozone research before his death in 1954.

After Gotz's death, the continuation of ozone measurements was secured by the efforts of several scientists, notably Hans Ulrich Dutsch, a professor at ETH Zurich, who was interested in ozone's effects on weather forecasting.

By the 1970s scientists were beginning to suspect that CFCs were among the chemicals that were destroying ozone. The Montreal Protocol helped reduce emissions of substances that were depleting ozone, though the stratospheric ozone layer is not expected to recover until the middle of this century.

Meanwhile, carbon monoxide, nitrogen oxide and hydrocarbon emissions are leading to a rise in ozone in the troposphere - the lowest layer of the Earth's atmosphere - where it is harmful. The Swiss measurements were useful in tracking ozone levels in both layers - and are still necessary today as scientists work to determine how ozone levels and wider climate change effects influence one another.

Some time after ozone measurements began in Arosa, the Physikalisch-Meteorologisches Observatorium in Davos (PMOD) began measurements of its own. These continued in parallel for a very long time but in recent years plans have been developed to move all of the equipment to Davos. This will be the end of an era for Arosa and its pioneering work. However, the legacy will continue as Switzerland continues to play a vital role in climatology.