Appointed director of the Soil Survey and Land Research Centre, his involvement in national and international scientific and advisory bodies grew: his role as special advisor to the Royal Commission on Environmental Pollution's inquiry into the sustainable use of soil led to an invitation to join the Intergovernmental Panel on Climate Change (IPCC). He contributed to the reports of the IPCC, which was awarded the Nobel Peace Prize in 2007. He demonstrated the role played by soil in the Earth's ecosystem and the impact of climate change on land degradation. Bullock was contributing lead author, along with Henri Le Houérou, to chapter 4 ('Land Degradation and Desertification') of Working Group II's contribution to the Second Assessment Report of the IPCC. As emeritus professor of land resource management of Cranfield University, he was instrumental in the establishment of the World Soil Survey Archive and Collection (WOSSAC) and in the development of the Soil-Net educational resource.