A 30 year retrospective analysis of Yukon River water chemistry neatly ties observed change in the state of the atmosphere to consequences and implications in the hydrosphere, cryosphere, biosphere and lithosphere. Now that we know this we can begin to predict, anticipate, plan, prepare, mitigate and adapt. If we didn’t know this we would be in for some rather unpleasant surprises. This is just one of many values of long-term water monitoring. The technicians taking water samples 30 years ago in harsh conditions could have had no idea how important their data would become. They would have thought they were monitoring a pristine system that is far too big and remote to suffer from anthropogenic influences. Never under-estimate the future value of your data.