Countdown: Dynamic mapping of agroclimatic tipping points

The aim of this thesis is to map the tipping points in climate resilience for the wheat sector in France by means of a 'countdown'. While the majority of preliminary studies predetermine time horizons (2050, 2070, 2100) to identify the expected cumulative impacts, this project proposes to estimate the time remaining before each of the main climate impacts affecting the sector. This approach will make it easier for decision-makers to prioritise and plan adaptation levers.

In order to better characterise the impact of climate on crops, the analysis will be based on agro- and eco-climatic indicators that describe water and energy transfers in the biophysical environment. In this way, the cascade effects of climate change – the extent of which is not necessarily proportional to changes in climatic variables themselves – will be considered. By studying these dynamics, it will be possible to identify the tipping points that would make it impossible to continue growing wheat in traditional production areas.

The aim of this thesis is therefore to develop a methodology for identifying the tipping points in climate resilience at a regional level, as well as the dates (years) on which they occur. The methodology will initially be developed for soft wheat (Triticum aestivum L.) and then applied to maize (Zea mays L.) to verify its generalisation. The study will be based on the phenological models and agro/eco-climatic indices developed in the unit, and will test various statistical approaches, such as TCIE and frequency analysis in a non-stationary context.