Impacts of climate on tropical crop production Tom Osborne a Andy Challinor a,b, Tim Wheeler b, Julia Slingo a a Department of Meteorology b Department. of Agriculture Crops and Climate Group

General Large Area Model for annual crops (GLAM; Challinor et al, 2004) Aims to combine: –the benefits of more empirical approaches (low input data requirements, validity over large spatial scales) with –the benefits of the process-based approach (e.g. the potential to capture intra- seasonal variability, and so cope with changing climates) Yield Gap Parameter to account for the impact of differing nutrient levels, pests, diseases, non-optimal management etc. general circulation model crop model

Forced with observed weather

Impact of extremes: rainfall distribution 1975 Total rainfall: 394mm Model: 1059 kg/ha Obs: 1360 kg/ha 1981 Total rainfall 389mm Model: 844 kg/ha Obs: 901 kg/ha

Impacts of extremes - temperature Also observed for rice (above) and groundnut Anthesis ~ time of flowering

Modelling high temperature stress Determine a flowering distribution Calculate impact of each high temp episode (this is a sum over all yield- determining flowers). The most severe high temperature episode impacts the harvest index. Simulate tolerance by choice of HTS parameters. Perhaps simulate escape by altering the flowering distribution in response to stress.

Importance of adaptation Number of years from period when the total number of pods setting is below 50%. Sensitive crop variety Tolerant crop variety

How do we intend to link to EPS? Use the climate model projections directly. What are our main questions requiring discussion in this meeting? How to get hold of the EPS output – password does not work? AJC What have we achieved so far? Incorporated effects of high temperature stress at flowering on yield and represented response to stress of different crop varieties. Q & A

Which WP6.2 tasks etc will we contribute to and when? Milestone 6.14: Completion of preliminary probabilistic assessments of climate change impacts using calibrated impact models Due Feb 2008 Task : Preliminary evaluation of the impacts of extreme events … for crops … from available climate projections Ongoing Task : Application of preliminary results from the EPS to impact models for estimating risks of extremes and risks of impacts. Ongoing (2 months unfunded)