Improvements in the ability to model El Nin˜ o and other large-scale
interannual climate variations have allowed for the development
of seasonal climate forecasts, predicting rainfall and temperature
anomalies for many places around the world. These forecasts have
allowed developing countries to predict shortfalls in grain yields,
with benefits for food security. Several countries communicate the
forecasts to subsistence farmers, which could allow them to mitigate
the effects of drought on their harvests by adapting their
cropping decisions accordingly. However, it has not been demonstrated
that subsistence farmers benefit from having access to the
forecasts. Here we present evidence of subsistence farmers using
the forecasts over multiple years to make different decisions and
significantly improving their harvests when they do so. In a
controlled study, farmers in Zimbabwe who reported adapting
their farming methods to seasonal climate forecasts significantly
improved their harvests over baseline amounts. Moreover, farmers
who had attended a brief workshop and learned more about the
forecasts were significantly more likely to use the forecasts than
were farmers who learned of the forecasts through non-participatory
channels.