Bjørn Hallvard Samset is a climate scientist working on atmospheric science and global modelling, and an active and experienced science communicator, author and public speaker. 

He studies the role of atmospheric aerosols in a changing climate, and notably the effects of local changes in emissions on regional and global climate. He mainly works with global climate models, and is active in a number of model intercomparison projects such as AeroCom, RAMIP and PDRMIP. In the IPCC 6th Assessment Cycle, Bjørn was a Coordinating Lead Author in Working Group 1.

Bjørn is also a regular newspaper science commentator, columnist, and has written several popular science books. and science commentator. He has previously worked on particle physics, with the ATLAS collaboration at CERN and the BRAHMS collaboration at RHIC. Bjørn has a PhD in Nuclear Physics from the University of Oslo (2006).