Zurich, Switzerland:
The glaciers in the Swiss Alps, a divine treat for tourists, are now endangered. Global warming and climate change is melting them faster than ever before. But what was the place's climate like long ago, before the world woke up to these threats?
One useful way is to dig deep into the glaciers which hold the clues. But it's not easy since drilling in cold high altitudes is very demanding.
Teams drill out ice cores bit by bit and then analyse the frozen water for the gasses trapped within, unravelling the climate hundreds of years ago.
These dark and light layers of ice reveal details of past climate like never before.
"We take samples from the glaciers' ice cores and look at its chemical composition. We study the chemical elements and try to understand how their climate and their past was," said Margit Schwikowski, a glacier chemist at the Paul Scherrer Institute, Switzerland.
Effectively, the glaciers are a history book which when read by trained scientists yield clues about the climate in the past.
The ice cores are carefully brought back to laboratories and maintained at -20 degrees Celsius. The cores are then cut to size in highly sterile conditions and then sophisticated instruments are used to analyse them.
There is no doubt that the climate is changing, but why is the climate changing? Scientists in Switzerland are using ice cores to understand what exactly is happening with the climate around us.