At the end of 2020, we'll take all the good news we can get, and a new study on modern crop development definitely falls into that category: It estimates that more than 100 million infant lives have been saved since modern crop varieties were introduced in the 1950s and 1960s.

While the spread of this so-called Green Revolution has not been consistent over time, it works out as an average 3-6 million young lives being saved each year, through crops that are more plentiful, more resistant to disease and pests, and of a better quality.

But the researchers also emphasize that there's much more that can be done – areas such as sub-Saharan Africa could benefit from greater adoption of modern crops, for example, following the sort of gains in food production that have been seen in Southeast Asian countries like India.

"If the green revolution had spread to sub-Saharan Africa like it did to South Asia, our estimates imply that infant mortality rates would improve by 31 percent," says economist Gordon McCord, from the University of California San Diego.

The numbers crunched by McCord and his colleagues cover 1961 (when modern crop varieties were introduced into the developing world) to 2000. The team looked at mortality rates of more than 600,000 children across 37 developing countries, combining public health surveys of women with geospatial crop data.

Over those years, researchers noticed an average reduction in infant mortality rates from 2.4 to 5.3 percent, as well as larger drops in mortality among male babies and in poorer households.

In fact, a substantial part of the reduction in premature infant deaths in the developing world can be put down to moves towards higher yielding cereal crops, the researchers say – which is an important consideration for parts of the world that are still lagging behind and where big improvements could be made.

"The health benefits of broad-based increases in agricultural productivity should not be overlooked," says McCord. "From the policy perspective, government support for inputs leading to a green revolution as well as investments in extension and R&D programs are important."

Wheat, maize, and rice are the key staple crops analysed in the course of the study, and as well as the benefits of using improved varieties of these crops, the findings also speak to the huge gains to be had from international cooperation – in this case the spread of these crops from the United States.

The next step is using this data to bring infant mortality rates down even further in developing nations. An increase in modern crop adoption from 0 to 50 percent in a global level could see a related drop of 33-38 deaths per 1,000 children, the researchers say.

There are some caveats to the research – which didn't factor in the increased use of fertilisers, irrigation, or pest control methods alongside the spread of modern crop varieties, for example. This is something future studies could analyse.

"Our findings therefore cannot be read to indicate that MVs [modern crop varieties] should be promoted at the expense of other agricultural technologies," write the researchers in their published paper.

"Rather, they speak to the importance of supporting productivity in agriculture as a means of improving lives in developing countries, including the lives of the poor in rural areas."

The research has been published in the Journal of Health Economics.