For three decades Professor Budd has played a dominant role in international research on polar ice. Based on extensive practical experience in Antarctica, he has produced theories and experimental confirmation of the large-scale behaviour of ice which he and his colleagues have used to study the interaction of ice-sheets and climate. His models provide explanations for the initiation and passing of ice ages, and simulate the response of Antarctica to future global warming. His experimental analyses of ice flow provide essential background for the study of ice-core proxy records of past climate. In general, his work unlocks many of the polar region keys to global change.