The 2013 John Dalton Medal is awarded to Michael Roderick for seminal contributions to the science of evaporation, including especially the role of vegetation and the interpretation of changes in evaporation in the context of global environmental change.
Like John Dalton, Michael Roderick is a true scientist of his age, a natural philosopher who has turned his mind to address a wide variety of problems in hydrologic science. His work has led to path-breaking contributions in the areas of ecohydrology (the role of vegetation in annual water balance, explanations of the Budyko curve, and new theories based on vegetation optimality) and remote sensing science.
Above all, however, it is his seminal contributions to the science of evaporation, including the interpretation of changes in evaporation in the context of global environmental change, for which Roderick is best recognised within hydrological science. Roderick’s contribution to understanding the origins of the documented decadal changes in pan-evaporation is truly seminal and transformative. Through consistent care in the analyses of historical pan evaporation data, clarity of thought, and brilliant innovation in formulating a method to identify the mechanisms responsible for recorded changes in pan evaporation, he transformed an extremely important subject area within hydrological science that had become confused by speculation, instead providing new and crucial insights. He overturned incorrect assumptions regarding the importance of one of Dalton’s controls on evaporation, i.e., vapour pressure deficit, and replaced this with evidence of the importance of the second of Dalton’s controls, i.e., wind speed. Building on this decisive breakthrough, he went on to use this new understanding to benefit the estimation of water resource availability on a global scale, again providing a direct analogy with the work of John Dalton.
Roderick’s work is outstanding in several respects: unconventionality, originality, creativity, and high quality. He is fearless, creative and prone to making new and important discoveries in hydrologic science. The breadth of his contributions is truly impressive. He has published in journals that range from ecology and plant sciences to water resources, atmospheric sciences and engineering. Even more impressive than the sheer number of papers is their scientific content: they contradict common theory, they criticise common beliefs, they test new theories, and they provide new explanations, sometimes from very different perspectives, which make them thought-provoking and innovative.
Roderick is a brilliant communicator and critical and broad thinker who has opened up alternative new directions to old lines of thinking in several fields. His findings have had a significant impact on the management of water-related systems globally. His energy and enthusiasm is infectious and he has played a leading role worldwide in bringing the international community together to dig deep and get to the bottom of critical questions of global environmental sustainability and change. His contributions to the evaporation paradox have had a tremendous impact, and the debate has been followed by most hydrologists and the wider community.