evidence: For latest figures see the NASA-GISS site [...] Mitchell (1953); already in 1938 Callendar adjusted for the effect, while admitting that "this is a matter which is open to controversy." Callendar (1938), p. 235. Additionally, the common practice during the 1950s of moving weather stations from downtown locations to airports, outside the "heat island," would give a spurious impression of cooling, but Mitchell and others allowed for that too in their calculations. BACK 23. Lamb (1977), pp. 709-10. BACK 24. Johnsen et al. (1970); Lamb (1977), pp. 529, 549. BACK 25. Emiliani (1966b). BACK 26. Hays et al. (1976). BACK 27. Mitchell (1972), p. 445; GARP (1975), pp. 37, 43; they cite a Manabe computer model of 1971 and Mitchell (1973). BACK 28. Broecker (1975). For more on Broecker's paper see the essay on solar variation; for the few obscure earlier uses of "global warming" see this footnote in the essay on The Public and Climate. BACK 29. Salinger and Gunn (1975). BACK 30. Damon and Kunen (1976); a brief argument on turbidity reducing high-latitude temperatures is in Bryson (1973), p. 9; see also Damon and Kunen (1978). A confirmation: Hansen et al. (1981). BACK 31. Lamb (1977), p.