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We characterise the variability in the physical properties of the luminousblue variable AFGL2298 between 1989-2008. In conjunction with published datafrom 1989-2001, we have undertaken a long term (2001-2008) near-IRspectroscopic and photometric observational campaign for this star and utilisea non-LTE model atmosphere code to interpret these data. We find AFGL2298 tohave been highly variable during the two decades covered by the observationaldatasets. Photometric variations of >1.6 mag have been observed in the JHKwavebands; however, these are not accompanied by correlated changes in near-IRcolour. Non-LTE model atmosphere analysis of 4 epochs of K band spectroscopyobtained between 2001-7 suggests that the photometric changes were driven byexpansion and contraction of the stellar photosphere accompanied bycomparatively small changes in the stellar temperature. Unclumped mass lossrates throughout this period were modest and directly comparable to those ofother highly luminous LBVs. However, the bolometric luminosity of AFGL2298appears to have varied by at least a factor of ~2 between 1989-2008, with itbeing one of the most luminous stars in the Galaxy during maximum. Comparisonto other LBVs that have undergone non bolometric luminosity conserving`eruptions' shows such events to be heterogeneous, with AFGL2298 the leastextreme example. These results - and the diverse nature of both the quiescentLBVs and associated ejecta - may offer support to the suggestion that more thanone physical mechanism is responsible for such behaviour. [ABRIDGED]

Bolometric luminosity variations in the Luminous Blue Variable AFGL2298