Methods are disclosed for achieving the catalytic combustion of a gaseous species in low temperature humid environments. The methods comprise the steps of obtaining a combustion catalyst composition comprising an amount of a precious metal supported on an ion-exchangeable alkali metal titanate substrate, and then exposing the species to the combustion catalyst composition in the presence of an oxygen containing gas and water vapour at a catalysis temperature below 200° C. and at a relative humidity above 0.5%. A novel desiccant-coupled catalytic combustion process and system are also disclosed.