Although benefit - transfer can provide a quick, low - cost approach for obtaining desired monetary values, the methods are often associated with uncertainties and potential biases of unknown magnitude. (obamawhitehouse.archives.gov)
I also find it more feasible that the KNOWN increase in surface temps across the ENTIRE surface of the ocean is responsible rather than an UNKNOWN change of UNKNOWN MAGNITUDE of UNKNOWN SIGN from thermal vents that cover only a relatively small percentage of the ocean floor. (joannenova.com.au)
Real but of unknown magnitude are the nonlinear «black swan» risks, such as warming permafrost feedback, changes to ocean currents, and potentially violent reactions from the human populations impacted. (powermag.com)