Dr Nick Pepin is Reader in Climate Science in the School of Environment, Geography and Geosciences in the University of Portsmouth. He is an expert in mountain climate change, leading the global effort to understand why mountain regions are experiencing more rapid environmental changes than elsewhere on the planet as a result of global warming. He has published highly cited research on elevation-dependent warming patterns (different rates of global warming at different elevations) and has field research ranging from the tropics to the Arctic. He has monitored changing weather conditions on Kilimanjaro for nearly 20 years, including the impact of deforestation on the mountain snows and associated temperature patterns, and his research in Finnish Lapland has also contributed to understanding reduction in snow/ice and changes in cold extremes in the Arctic. He has collaborated with scientists across the world including in China, Europe and the USA. He teaches climate science on the Geography and Environmental Science degree programmes, and has instilled a love of weather and climate in many generations of students. He is extremely pleased to provide a commentary on the Blue Marble image from a climate perspective.