The response of stomatal conductance to vapor pressure deficit over
global wheat areas in CMIP6 warming projections
Abstract
Climate change is expected to alter the conditions in which plants
develop. The mechanisms by which plants can adapt to changing conditions
must be studied in terms of the magnitude of their response and the
implications for productivity. Recognizing wheat as a main crop
sustaining global livelihoods as well as the need for long-term
adaptation strategies to climate change, this work assesses the response
of wheat stomatal conductance (gs) to changes in vapor pressure deficit
(VPD) associated with global warming in three future scenarios from the
Coupled Model Inter-comparison Project phase 6 (CMIP6). We used multiple
datasets and a modeling approach to estimate gs as a function of
atmospheric variables only over global wheat areas. The results show a
sustained increase in both temperature and VPD in the historical period
and future CMIP6 scenarios, and a generalized decrease in wheat gs that
becomes clear from around the year 2040. The pattern of change is
spatially divergent, with areas that present increases in relation to
the historical average, which mostly concentrate towards high latitudes.
Negative trends in gs area mainly observed in North America, Southern
Europe, North Africa and Asia. Notwithstanding, the proportion of areas
of positive change in gs tend to decrease in warmer climate scenarios.
gs is more sensitive to changes in VPD than to global warming, which
implies that the areas of negative trends in gs could expand to higher
latitudes. These results may assist the regional focus of long-term
wheat adaptation programs to climate change.