A major supplier of maize to fill the gap in Zimbabwe’s last harvest is Tanzania, which had a significant surplus thanks to the same El Nino weather conditions that generated a drought across much of Southern Africa, but generated above average rainfall across most of East Africa.
El Nino and La Nina phenomena change weather conditions across large swathes of the globe, bringing drought or increased rainfall.
But the two tend to work in opposite directions.
Areas like Southern Africa that are likely to be hit by drought in El Nino years are likely to have above normal rainfall in La Nina years.
Areas like East Africa, which usually have extra rainfall in an El Nino year, often have reduced rainfall in a La Nina year.
What makes this effects reversal so useful is that the two regions, Southern and East Africa, are next door to each other, which opens up a lot of possibilities for farmers.
Meteorological experts in the two regions are getting ever better at estimating the probabilities of drought and heavier rainfall.
They do not always get it right, because they are dealing in probabilities, not mathematical facts, and because so many factors affect rainfall patterns.
But nonetheless, as they understand more and can compare previous seasonal data with the latest data, they are able to offer more valuable forecasts of what is likely to happen.
Now they need to go a step further and start giving a wider view than just Southern Africa or just East Africa.
We all need to know what is likely to happen in the other region and how this will effect harvests.
But as that cooperation and spread of forecasts becomes generally available, both regions can benefit.
If, for example, we know that there is a high probability that most of Southern Africa is likely to be hit by drought one year, while East Africa is likely to have above average rainfall, it would make sense to ensure in advance that East African farmers know they have an almost guaranteed market just down the road.
Zimbabwe was keen to buy some of the Tanzanian surplus because it was almost next door and so could be delivered at lower cost.
Obviously, we have to pay global prices for the grain, but we are only shipping it a few thousand kilometres, not halfway across the world.
On the other hand, farmers in Malawi, Zambia and Zimbabwe would be exceptionally interested to know that if they have better rains, harvests are likely to be reduced in East Africa. Then everything extra they plant can be sold with buyers keen to find a source that does not cost an arm and a leg in transport costs.
One problem of producing more than you can eat is that you need a market for the surplus.
Governments can, and do, buy some of the extra grain for future years. But there are limits and there are often better uses for the limited capital sums available to most African governments.
But if governments in the two regions can work together to look at how harvests in any particular year, under the predicted weather conditions, are likely to pan out, then the inverse effects of El Ninos and La Ninas can give overall food security across half a continent and ensure that the more fortunate farmers that year move ahead fast and expand production.
Warming global temperatures due to climate change will make life more difficult for much of sub-Saharan Africa, so we need to think about every advantage we can gain through cooperation and practical inter-regional and continental planning.
This should not be difficult.
We are now on good terms with each other with Tanzania in the pivotal position of seeing itself belonging to both regions, the South and the East, and so able to perhaps take a lead in turning pan-Africanism into practical planning.
At the same time, we can start upgrading our transport links between the two areas.
With more traffic almost guaranteed, the required investment makes sense, but farmers will not be the only ones to benefit from better and cheaper transport between Southern and East Africa.
Industrialists in both areas should be keen on spreading their markets and consumers will win out with more competition. An ill wind can bring some interesting and very positive results.
