Hadronic cross-sections in two photon processes at a future linear collider

In this note we address the issue of measurability of the hadronic cross-sections at a future photon collider as well as for the two-photon processes at a future high energy linear e+e- collider. We extend, to higher energy, our previous estimates of the accuracy with which the γ γ cross-section needs to be measured, in order to distinguish between different theoretical models of energy dependence of the total cross-sections. We show that the necessary precision to discriminate among these models is indeed possible at future linear colliders in the Photon Collider option. Further we note that even in the e+e- option a measurement of the hadron production cross-section via γ γ processes, with an accuracy necessary to allow discrimination between different theoretical models, should be possible. We also comment briefly on the implications of these predictions for hadronic backgrounds at the future TeV energy e+e- collider CLIC. (author)