The phrase "dynamical changes" means alterations or shifts that happen over time, in an energetic or active manner. It refers to ongoing modifications or transformations in a system or situation. Full definition
Did they really think that the public, journalists, and sceptics would read (or even understand) the small print in the sea level column stating «Model - based range excluding future rapid dynamical changes in ice flow»? (realclimate.org)
Estimates of the decadal variability in ice sheet mass loss (11) suggest the impact on acceleration estimates is ∼ 0.014 mm / y2 for a 25 - y time series, in the absence of rapid dynamical changes in the ice sheets. (pnas.org)
Such dynamical changes favor certain types of weather situations in some regions and others elsewhere. (sciencedaily.com)