Carmeli remained active in research in theoretical physics, as well as becoming involved in science on the world stage. He was a member of many scientific societies, including the American Physical Society, American Association for the Advancement of Science, and The New York Academy of Sciences, and was listed in both Who's Who in the World and Who's Who in Science and Technology. He actively refereed and reviewed hundreds of scientific works by noted scientists seeking publication in over a dozen scientific journals. He held visiting professorships at the C. N. Yang Institute of Theoretical Physics of the State University of New York at Stony Brook, the University of Maryland, the International Center for Theoretical Physics in Trieste, the Max Planck Institute for Astrophysics in Munich, the University of Massachusetts, Colgate University, Queen Mary College of the University of London, and the State University of Campinas in Brazil. He was invited four times by the Swedish Royal Academy of Sciences to nominate candidates for the Nobel Prize in Physics. He was also invited four times by the Wolf Foundation to nominate candidates for the Wolf Prize in Physics.