Canadian astronomers Bruce Campbell, G. A. H. Walker and Stephenson Yang publish radial-velocity observations suggesting that an extrasolar planet orbits the star Gamma Cephei, although its existence is not confirmed until 2003.
^Campbell, B.; Walker, G. A. H.; Yang, S. (1988). "A search for substellar companions to solar-type stars". The Astrophysical Journal. 331: 902. doi:10.1086/166608.
^U.S. Senate, Committee on Energy and Natural Resources, "Greenhouse Effect and Global Climate Change, part 2" 100th Cong., 1st sess., 23 June 1988, p. 44: "global warming has reached a level such that we can ascribe with a high degree of confidence a cause and effect relationship between the greenhouse effect and the observed warming."