There is considerable evidence that Africa is the continent that will be hit the first, most and worst by climate change.
Agricultural productivity, already among the world’s lowest, could in several African countries fall by 50 percent in 10 years because of higher and more variable temperatures, which in turn could lead to faster desertification, rising sea levels, and more frequent droughts, floods and typhoons.
One reason why African agriculture is particularly vulnerable is that only 7 percent of cultivable land is irrigated—the rest is dependent on rainfall. Yet irrigated land can have yields that are five times those of rainfed land.
So why is there so little irrigation in Africa? Presumably, because political and administrative costs lead the total costs to exceed the benefits of irrigation.
In a recent paper , Aziz Bouzaher, Brian Ngo and I asked the question: Could the threat of climate change (or the benefits of avoiding the harmful effects of climate change) tip the balance in favor of more irrigation?
In a subsequent presentation  at the Energy-Climate Change-Technology conference in Bergen, Norway , Aziz and I showed some calculations for the Zambezi River basin that suggested that this was possible.
Specifically, the benefits of tripling irrigated area (in terms of the value added of increased crop yields) is about $1.7 billion, which is only slightly higher than the cost (about $1.5 billion). But when you add the avoided damage from climate change, the benefits of tripling irrigated land jumps to $3.3 billion, clearly tipping the scales in favor of more irrigation.
If the calculation for the Zambezi river basin generalizes to other areas, and some of the other issues discussed in the paper—such as exploitation of Africa’s hydropower potential, sustainable land management, and reduced or avoided deforestation—also result in benefits’ (including reduced damage from climate change) exceeding costs, climate change could be a development opportunity for Africa.