Less erosion, less warming

Blog by
11 November 2010

I recently met with a Member of the Bangladesh Parliament to discuss the potential for mitigation in the agricultural sector under IIED’s work on the economics of climate change in the agricultural sector. Agriculture produces 10–12 per cent of total global emissions but also has considerable mitigation potential — 70 per cent of which is in developing countries — and I expected the Honourable Member, a well known climate change champion, to back the cause. But he did not seem entirely convinced. Why should decision makers listen? What’s in it for them?

He might have had a point.

The Earth’s atmosphere suffers from the perpetual Tragedy of the Commons — the costs of any mitigation action are concentrated on whoever undertakes that action, but the benefits accrue to everyone on the planet. There is little incentive for those not bound by Kyoto-style emissions reductions targets, i.e. developing countries, to do very much about it.

One solution to this is to pay developing countries to reduce their emissions, giving the Honourable Member and his decision-making friends a reason to act. Another is to get them to undertake mitigation actions for different reasons altogether. I pick the latter.

What benefits?

So how might this work in practice?

Due South recently discussed the new film More People, More Trees, which gives an update on work carried out in the early 1990s documenting spectacular environmental recovery in the Machakos region of Kenya and the Central Plateaux of Burkina Faso.

The Central Plateaux truly epitomised the Sahel drought of the 1970s. With rainfall deteriorating and a growing population to feed, farming intensified with the result that vast swathes of agricultural land were reduced to bare rock. Crops failed, cattle died and people starved. But then something happened that put the Central Plateaux on a path to recovery.

The farmers began to change how they farm — and the results are simply staggering. They began to build stone lines, which slow down any water running off the fields and cause it to infiltrate, thereby leaving the fertile topsoil in the fields. They also planted their crops in ‘zai’, small dug-out holes filled with manure. By combining these two approaches, the farmers have regenerated their land from barren waste to fertile field.

The farmers can now grow a range of crops including millet, beans and groundnuts, and benefit from larger and more reliable harvests. The region is scattered with trees. Such has been the ‘greening’ caused by these changes in practice that it has been picked up by satellites surveying the region as separate from and in addition to any climatic-induced trends.

The jump to mitigation

It doesn’t take much to see the implications of the More People, More Trees phenomenon for climate change mitigation. Trees are made of carbon (about 45 per cent of their dry mass is carbon) and more trees means more carbon is in the form of tree, and not in the form of atmospheric carbon dioxide. Of even more significance, the agricultural practices that regenerate degraded soil, such as those adopted in the Central Plateaux, act to increase the carbon content of the soil, again storing more carbon out of the atmosphere.

If the use of stone lines and zai, and a whole range of other best management practices, can be spread around the world, the technical potential for climate change mitigation is considerable: the Intergovernmental Panel on Climate Change puts the figure at between 5.5 and 6.0 billion tonnes of CO2 equivalent per year by 2030, slightly larger than the total emissions from the agricultural sector.

Incentivising action

Now, I ask, how are we most likely to persuade farmers to take on such practices? By supporting the spread of information about the benefits of these management practices to agricultural production, or by paying farmers? The latter brings up a whole new range of questions — who will pay? How will we ensure the money actually gets to the farmers? How will we check what they are really doing? And what impact are their actions having on terrestrial carbon stores?

Call me a sceptic, but I’m willing to guess that the UN, national and local government institutions and the technology aren’t ready for this and won’t be for some time. If we want to promote climate change mitigation in developing countries we had better come up with some other reasons to do it, and fast. Demonstrating the direct agricultural benefits of best management practices to local people would be a good start.