Dome A in Antarctica, site of some of the continent's thickest ice, is one proposed location for drilling a core one million years old or more. Credit: JEAN DE POMEREU, INTERNATIONAL POLAR FOUNDATION

Some of scientists' gravest concerns about future climate change are rooted in the past. Records studied by paleoclimatologists reveal that the more extreme possibilities for this century and beyond — temperatures soaring, ice sheets vanishing, fertile lands withering into deserts — were realized previously on Earth when atmospheric greenhouse gas levels surged. This summer, experts working to understand how and why such changes occur met in Columbus, Ohio, at the Byrd Polar Research Centre, one of the world's top facilities for reconstructing past climates.

The scientists who gathered at the American Geophysical Union's Chapman Conference on Abrupt Climate Change, held 15–19 June, bring a diversity of tools to bear in understanding the past. Among the proxies they use are ice cores, tree rings, corals and marine sediments. Though each has its own merits, ice cores have provided unparalleled insights into the nature of the Earth's climate system. Offering records of climatic history whose detail and completeness are unmatched, ice core data stretch back 800,000 years and are conveniently located in some of the world's most climatically sensitive regions.

Two new features on Nature Reports Climate Change pay homage to the work of scientists who, over the last few decades, have been tireless in their efforts to extract clues about the Earth's past climate from air bubbles, isotopes and dust particles trapped in ice.

First, a timeline of polar cores documents in fine detail the discoveries of scientific pioneers, from the first efforts to read ice records through to today's hunt for ice a million years old or more. Complementing this chronology of scientific discovery is an interactive map layer for Google Earth (download map layer; download Google Earth). Through a simple download, you can visit the sites where polar researchers have holed up year after year, drilling thousands of metres of Greenland or Antarctic ice before hitting bedrock.

Also in this issue is an exclusive interview with world-renowned glaciologist Lonnie Thompson. In his quest to understand how ice is changing atop the world's mountains, Thompson has spent more spent more time above 20,000 feet than any other human being. The glaciers he studies not only provide water for millions worldwide, they act as sentinels that tell us the climate system is changing.

Such endeavours come with scientific challenges as well as personal ones. As understanding abrupt climate change becomes increasingly crucial, ambitious plans for studying these icy environs will be ever more important.