Assessments of the relationships between crop productivity and climate change rely upon a combination of modelling and measurement. As part of this review, this relationship is discussed in the context of crop and climate simulation. Methods for linking these two types of models are reviewed, with a primary focus on large-area crop modelling techniques. Recent progress in simulating the impacts of climate change on crops is presented, and the application of these methods to the exploration of adaptation options is discussed. Specific advances include ensemble simulations and improved understanding of biophysical processes. Finally, the challenges associated with impacts and adaptation research are discussed. It is argued that the generation of knowledge for policy and adaptation should be based not only on syntheses of published studies, but also on a more synergistic and holistic research framework that includes: (i) reliable quantification of uncertainty; (ii) techniques for combining diverse modelling approaches and observations that focus on fundamental processes; and (iii) judicious choice and calibration of models, including simulation at appropriate levels of complexity that accounts for the principal drivers of crop productivity, which may well include both biophysical and socio-economic factors. It is argued that such a framework will lead to reliable methods for linking simulation to real-world adaptation options, thus making practical use of the huge global effort to understand and predict climate change.

Understanding farmers’ perceptions of how rainfall fluctuates and changes is crucial in anticipating the impacts of changing climate patterns, as only when a problem is perceived will appropriate steps be taken to adapt to it. This article seeks to: (1) identify southern African farmers’ perceptions of rainfall, rainfall variations, and changes; (2) examine the nature of meteorological evidence for the perceived rainfall variability and change; (3) document farmers’ responses to rainfall variability; and (4) discuss why discrepancies may occur between farmers’ perceptions and meteorological observations of rainfall. Semi-structured interviews were used to identify farmers’ perceptions of rainfall changes in Botswana and Malawi. Resulting perceptions were examined in conjunction with meteorological data to assess perceived and actual rainfall with regards to: what was changing (onset, duration or cessation), and how it was changing (amount, frequency, intensity or inter-annual variability). Most farmers perceived that the rains used to start earlier and end later. Meteorological data provided no evidence to support farmer perceptions of rainfall starting as early as September (south Malawi) or October (Botswana); however, a high inter-annual variability in the timing of the onset was observed alongside an increasing number of dry days and declining amounts of rainfall at the onset and cessation of precipitation. While some rainfall patterns are associated with El Niño-Southern Oscillation (ENSO) fluctuations and larger-scale changes, one explanation for the differences between farmer perceptions and meteorological evidence is that rainfall changes can be easily confused with changes in farming system sensitivity. Our findings suggest that scientists, policymakers, and developers of climate adaptation projects need to be more in tune with farmers' and extension workers’ understandings of how weather is changing in order to improve adaptation policy formulation and implementation.