Abstract
Successful adaptation to climate change at regional scales can often depend on understanding the nature of geomorphological responses to climate change at those scales. Here we use evidence from landscapes which are known to be environmentally sensitive to show that geomorphological change in response to shifts in climate can be highly nonlinear. Our study sites are two mountain massifs on the western coast of Ireland. Both sites have similar geological and Pleistocene glacial histories and are similar topographically, geomorphologically and in their climate histories. We show that despite these similarities their response to late Holocene, climate change has differed. Both massifs have responded to short-term climate changes over the last 4500 years that are considered to have been uniform across the region, but these climate changes have resulted in highly differentiated and nonlinear landscape responses. We argue this reflects nonlinearity in the forcing–response processes at such scales and suggests that current approaches to modelling the response of such systems to future climate change using numerical climate models may not accurately capture the landscape response. We end by discussing some of the implications for obtaining decision-relevant predictions of landscape responses to climatic forcing and for climate change adaptation and planning, using regional climate models.
Highlights
Information about climate change impacts at local and regional scales is widely sought in support of adaptation strategies and as motivation for mitigation efforts (Jenkins et al 2009; Wise et al 2014; Lowe et al 2018)
Steeper slopes should correlate with catchment responsiveness, i.e. we would expect a steep catchment to react more rapidly to a climate forcing, but there is a threshold at which slope angle will preclude sediment cover, so rock slopes and response may be very limited to climate forcing, though all slopes under investigation are sediment mantled
These factors imply that regional predictions of landscape response to sustained climate change and/or individual high-magnitude weather events are likely to be very difficult to make for some landscapes and require a probabilistic geomorphological framework (Church 2003) that includes sensitivity to initial conditions, one which is complementary to that found in some climate projections (Corti et al 2015)
Summary
Information about climate change impacts at local and regional scales is widely sought in support of adaptation strategies and as motivation for mitigation efforts (Jenkins et al 2009; Wise et al 2014; Lowe et al 2018). Substantial efforts have been made to quantify uncertainty in the climate’s response at spatial scales relevant for adaptation planning, but the consequences of any given change in climatic variables on the landscape are either not considered or at best assumed to be linearly proportional to forcing. There is a tendency, to assume that so long as individual geomorphological processes are understood, the responses can be predicted with confidence. When adaptation planners, such as water managers, use climate projections, they implicitly assume that the geomorphological response is predictable as a consequence of a given climate projection. Geomorphological sensitivity to climate forcing varies significantly according to the type of geomorphic system, but our results indicate that very similar geomorphological systems can exhibit radically different responses to the same forcings; this represents an uncertainty similar to that arising from the initial value sensitivity of many nonlinear systems
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
