[eesmith]

The article does not use the phrase "record breaking drought".

The phrases are: 1) "They are known as the "hunger stones," and they were chosen in the past to record low water levels", 2) "As Europe wilts in the sweltering, record-breaking harshness of summer 2018", 3) "with water levels hitting record lows in Europe".

The last two provide links where I think it's clear that they refer to modern record keeping, eg, daily measurements of temperature, rainfall, water depth, etc.