Midgley has focused on research and teaching on climate change risks and solutions in social-ecological systems in southern Africa since 1984. A-rated by the National Research Foundation in Earth Sciences, and previously A-rated in Plant Sciences, he is a Fellow of the Royal Society of South Africa, a Lifetime Humboldt Research awardee, the RSSA Marloth Medal recipient for lifetime scientific contributions, and is rated amongst the most influential scientists in climate change (Thomson Reuters 2022), and highly cited (Thomson-Reuters 2014). As co-ordinating lead author of IPCC he is a co-awardee of the Nobel Peace Prize (2007). 

He served as co-ordinating/lead/contributing author for IPCC 3rd, 4th, 5th, and 6th assessments (1999 to 2022), and CLA for the IPBES Global and Land Reports, the combined IPBES/IPCC risk assessment, and co-chaired the CBD Climate Change and Biodiversity ad hoc Technical Expert Group Report (2009).  He chaired SA’s Global Change Science Committee in the 1990s and 2000s, growing the annual budget to over R100 million, transforming the sector. As SANBI Chief Director, he facilitated SANBI registration as National Implementing Entity for the UNFCCC Climate Change Adaptation Fund (over R100 million annual budget), prior to taking up a Professorship at Stellenbosch University in 2014. He has served as trustee and past President and Vice-President of the US-based JRS Biodiversity Foundation, leveraging a USD50 million endowment supporting African biodiversity informatics. 

He currently works in a wide variety of southern African ecosystems, and leads efforts by Stellenbosch University’s School for Climate Studies and Center for Invasion Biology to build multidisciplinary approaches to teaching, researching and communicating climate change risk. He has graduated many MSc and PhD students, with several of his students now occupying senior positions in SA government and national and international academic institutions and NGOs.