Antarctic and Southern Ocean science is vital to understanding natural variability, the processes
that govern global change and the role of humans in the Earth and climate system. The potential for new
knowledge to be gained from future Antarctic science is substantial. Therefore, the international Antarctic
community came together to ‘scan the horizon’ to identify the highest priority scientific questions that
researchers should aspire to answer in the next two decades and beyond. Wide consultation was a
fundamental principle for the development of a collective, international view of the most important future
directions in Antarctic science. From the many possibilities, the horizon scan identified 80 key scientific
questions through structured debate, discussion, revision and voting. Questions were clustered into seven
topics: i)Antarctic atmosphere and global connections, ii) Southern Ocean and sea ice in a warming world,
iii) ice sheet and sea level, iv) the dynamic Earth, v) life on the precipice, vi) near-Earth space and beyond,
and vii) human presence in Antarctica. Answering the questions identified by the horizon scan will require
innovative experimental designs, novel applications of technology, invention of next-generation field and
laboratory approaches, and expanded observing systems and networks. Unbiased, non-contaminating
procedures will be required to retrieve the requisite air, biota, sediment, rock, ice and water samples.
Sustained year-round access toAntarctica and the Southern Ocean will be essential to increase winter-time
measurements. Improved models are needed that represent Antarctica and the Southern Ocean in the
Earth System, and provide predictions at spatial and temporal resolutions useful for decision making.
A co-ordinated portfolio of cross-disciplinary science, based on new models of international collaboration,
will be essential as no scientist, programme or nation can realize these aspirations alone.