The increasing fossil fuel CO2 signal in surface ocean waters, superimposed upon the natural background, has now reached the level of about 2mg kg-1, and thus, if we were to conceive of this as a separate signal, it has become a new component of the salinity of sea water in its own right. By the year 2100, under the IPCC Business as Usual scenario, the fossil fuel signal will exceed in mass the contributions of fluoride, boron, or strontium ions to the salinity of the surface ocean waters, and will reduce the pre-industrial carbonate iron concentration by about 55%. However the net effect of this massive chemical transfer to the ocean has not been to cause a haline contraction, but to increase the volume of the ocean by about 330¿109 m3 today. The water flux from fossil combustion, of about 10.5¿109 m3 yr-1, adds to this volume change.¿ 1997 American Geophysical Union