It is also emphasized that the increase of population size is by far the most important factor causing the very large increase of demand for food calories in 2050, and that the UN population forecast (used for this study) have proven to be globally reliable, although the regional forecasts have been less reliable.
(the UN population forecast; to be; globally reliable) (the regional forecasts; have been; less reliable) (the most important factor; causing; the very large increase of demand for food calories in 2050) (the UN population forecast; used; for this study)
the UN population forecast the regional forecasts the most important factor the UN population forecast
to be have been causing used
globally reliable
less reliable
the very large increase of demand for food calories in 2050
for this study