Methods and systems for estimating remaining or utilized scrubbing capacity of a gas scrubber are described. Inside the gas scrubber, a reaction gas is produced by an exothermic or endothermic reaction. Temperature sensors are positioned along the gas flow path, and temperature readings are obtained. Temperature differences between pairs of adjacent temperature sensors are determined. The largest temperature difference for each such pair is recorded. A recent temperature difference is normalized by dividing the recent difference by the largest recorded for the same pair. One or more of the normalized temperature differences may be weighted. The normalized temperature differences and/or the weighted temperature differences are combined to provide a life-value, which is indicative of the remaining or utilized scrubbing capacity of the gas scrubber.
