A second climate smart agricultural revolution in the Andes

Climate change is impacting the lives of potato farmers in the Andean region, intensifying damage from pests and diseases, increasing risk of soil erosion and contributing to loss of biodiversity.

In an award-winning presentation at the 10th World Potato Congress in Cusco, Peru, Graham Thiele, Director of the CGIAR Research Program on Roots, Tubers and Bananas (RTB) looked to the past to see what lessons can be drawn from the way in which the Wari and Inka Empires adapted to a warming climate one thousand years ago.

In the following Q&A with the International Potato Center (CIP), Thiele breaks down the history, the evidence, and key actions that are needed to respond to these challenges.  

What was the first Pan-Andean Climate Smart Agricultural Revolution, and when did it take place?
The first Pan-Andean Climate Smart Agricultural Revolution took place around 1,000 to 1,400 AD. This was a time of climate change and a warming environment. Despite this the Wari and Inka Empires were able to reconfigure and intensify Andean cropping systems at the same time as they made them more resilient and robust in the face of this climate change.

What evidence is there that climate innovation took place at this time?
What we have is something really neat, it’s kind of like a dashboard of changes in biology and local erosion processes and it comes from lake cores, from a dried-up lake near to Cusco, Peru. What we can see from these lake cores is that there was a peak in sedimentation around the 12th century which then tapered off. We think that peak was associated with the construction of terraces that led to momentarily increased soil loss and then stabilization.

We can also see a lot of macro-carbon coming from fires prior to that period, which then drops off too. This indicates a control of fire and a shift to a more permanent cropping system, as previously vegetation would have been burned to create space for agriculture. There is also a sharp increase in pollen from aliso trees, which the Inka were managing as agroforestry systems. So, there was a host of complex of changes that together facilitated a more sustainable and resilient cropping system in the Andes, with a reduction in CO2 emissions.

How did the warmer climate affect their cropping systems?
The effects of global warming in the Andes at that time, made it possible to cultivate maize further up the mountain slopes. That was linked with a shift of potatoes upwards to higher altitudes. So the configuration of potato, maize and other crops across that vertical space was changing, as were cropping practices – particularly with the introduction of terracing.

Peru’s Sacred Valley is hotspot of biodiversity for potato. Photo: H.Holmes/RTB

What is the benefit of terracing for potato farming?
Terracing is very good for cropping because you have stabilization of slopes. You have accumulation of soil nutrients by reducing soil loss, and you’ve also got improvements in water management with reduced run-off and irrigation.

What kind of institutional change took place at the time that allowed for Andean societies to introduce extensive terracing?
The Inka Empire was a bureaucratic and very hierarchical state, that developed different ways to manage people. They had a taxation system based mainly on maize and kept registers of people who paid tribute. The state was pushing for increased intensification of agriculture through terracing, in order to create surplus crops – primarily maize – for purposes of taxation. Potatoes would have been very much part of people’s lives and food security but weren’t so central to the Inkas tax regime.

Restored Inka terraces in Pisaq, Peru. Photo: H.Holmes/RTB

What evidence is there of climate change related impacts today?
There is compelling evidence of climate related impacts today. We can see reductions in the size of some glaciers in the Andes which is being associated with increased instability of water flows. In terms of direct impacts on agriculture, we’ve already seen that native potatoes which used to be grown at lower altitudes are climbing up the hillsides in search of lower temperatures. In the past 15 or 20 years, we’ve seen both bitter and floury varieties move over 200 meters upwards. There is also an intensification of several insects, pests and diseases. Modelling of projected increase in temperature and rainfall suggests that many farmers growing native potatoes will have to make several more sprays to control late blight which is a very damaging potato disease. Similarly, the Andean potato tuber moth, will be able to complete more lifecycles as the temperature increases and that going to lead to more damage to potatoes when moths multiply in potato stores, creating significant losses for farmers. 

What we can see is that climate change accelerates problems that were already there and makes them worse. Farmers’ local knowledge and practices may not be sufficient to keep up with the pace of climate change.

A young girl holds a native potato variety at her mother’s stall in Cusco, Peru. Photo: H.Holmes/RTB

How can what took place during the first climate smart revolution inform what we do today?
A good example is through agro-forestry. We’ve seen a significant loss of trees and especially local species in Andean spaces. We know from looking at agricultural records that agro-forestry was very important for stabilizing hillsides which can erode due to more erratic and intense rainfall. So, we need to think about potatoes in a more holistic way, not just the crop itself, but the whole environment around that crop.

It would also be great if we could restore some more of the Inka terraces, but there are other ways of managing slopes these days that are cheaper and more cost-effective. It’s important that we learn from the past, not as a blueprint, but to look at the ways institutional change occurred across a very large geographic space in a Pan-Andean way and have a modern version of what the Waris and the Inkas were able to do.

What are some of the ways that CIP and RTB are helping farmers adapt to the climate related challenges you have described?
One of the ways that CIP and RTB are helping communities to adapt to these challenges is through participatory plant-breeding. As I mentioned, a warming environment means that some potato varieties are being pushed up hillsides. So, what we would like to do is have new potato varieties which have the benefits and diversity of those older ones, but which are more resistant to diseases like late blight. CIP is working with national partners, such as INIA, on research to use Andean germplasm to breed varieties more adapted to climate change stresses. Some of these such as Puka Lliclla have already been released and are being adopted in the Andes.

View the full presentation via SlideShare below: