The phrase "transient response" refers to how a system or device reacts to changes or disturbances. It specifically describes the initial and temporary behavior of the system before it settles into a steady state. Full definition
It assumes «business as usual», and a consensus sensitivity and perhaps a slightly fast transient response if we take the vertical line to represent 2100. (planet3.org)
Even an initial step change in external forcing can't do that (except for a merely transient response). (tamino.wordpress.com)
Smaller displacement engines with high specific torque and boost levels require fast transient response, especially at low engine speeds, in order to be a valid replacement for larger displacement engines. (greencarcongress.com)