That somewhat depends on what you mean by 'significant' and 'catastrophic' but I believe the way the model goes is that if X% of coins are lost that means that the value of all outstanding coins will go up by X%, and if the rate of breakage goes from Y% annually to Y*Z% annually then the value of all coins will go up by a factor of Z. This is of course an idealized model in steady state, but gives some idea of scale.