Drilling into the frozen past

Review of a Lee Hotz article

Leave your comfy, warm living room, and venture south to the bottom of the world where you'll hit Antarctica, the highest, windiest, driest and coldest place on the planet. The entire continent has been drowned below sea level by the sheer mass of ice weighing it down. The ice mass represents a unique opportunity, to peer thousands of years into the past and observe incredibly detailed pictures of the earths ever changing climate.

A team of 45 scientists and engineers from the University of Wisconsin are drilling deep into the ice at location named WAIS Divide to extract clues as to the future of climate change. The ice contains a precise record of the rise and fall of greenhouse gases and temperature as far back as the last ice age.

Snow falls in huge quantities at WAIS Divide, with each snow fall forming a layer which is slowly compressed as it becomes buried by later snow storms. But its not just snow thats buried. Storms wash out dust, soot and trace chemicals from the atmosphere and deposits them on the fallen snow, year after year. We can observe calcium deposits from desert formation, soot from distant wild fires and methane levels indicating the strength of pacific monsoons, but most importantly each layer also traps the air itself. Roughly 10% of an ice layer is ancient air, a record of greenhouse gases, carbon dioxide, nitrous oxide, all unchanged since it was locked away thousands of years ago.

Drilling for Arctic ice isn't easy. So much snow falls at WAIS Divide the research team are practically living and operating a $8 million drill underneath the snow. They biopsy 10 feet long ice cores 10 times a day which equates to 360 years into the past per day. The ice cores are very susceptible to damage and contamination, and need to be kept at minus 20 degrees Celsius, so the team must work in a giant fridge located at the coldest place on earth. The samples they extract are shipped out to 27 independent labs across the world where they are analysed for 40 different trace elements at concentrations as low as 1 part in a quadrillion.

Why continue such obviously difficult research? Don't we know greenhouse gases are having adverse effects already? Greenhouse gases are detrimental to climate, but what we don't know is precisely what affect human activity will have on natural climate patterns, such as winds, ocean currents, precipitation rates, and cloud formation. These factors will affect billions of lives.

Snow storms have given antarctic ice an unprecedented knowledge of climate change, we just need to make sure we ask it lots of questions.

For more information on the WAIS Divide project see their web site.