Research
Current and recent projects
The Economics of Biodiversity Additionality (2022-25)
(1) ‘Spatial-economic determinants of forest regeneration in the Amazon’ (with Lykke Andersen, Ben Balmford, Sabrina Eisenbarth, Ben Groom, Ville Inkinen, Fabiana Karina, Sarah Meier, Lorenzo Sileci, and Diana Weinhold)
(2) ‘The paradox of conservation policy layering’ (with Ben Groom and Lorenzo Sileci)
Funded by the Natural Environment Research Council, funding call: ‘Economics of Biodiversity’.
'Public land-use policies have improved biodiversity on the world’s grasslands' (2023-)
(with Kirara Homma, Jinfeng Chang, Hadi and David Wuepper)
Biodiversity loss on grasslands driven by management intensity is a serious global problem. Many countries have implemented policies to improve the sustainability of grassland management, yet large-scale empirical evidence on the policy impacts is lacking. Despite their global importance, grasslands commonly receive less attention than forests and croplands. Here, we evaluate how public agri-environmental land-use policies have globally influenced biodiversity on grasslands. We leverage the largest ground-based bird observational data and satellite-derived data of land cover and grassland conditions at a resolution of 1 km2 annually for almost two decades, spanning the globe. Combining two different spatial econometric approaches, we find that, on average, countries’ policies have successfully regulated management intensity and increased biodiversity on grasslands, as measured by bird species richness. Results suggest a policy trade-off, that is, each policy has increased species richness by 1.4 for all birds, as well as by 0.07 for threatened birds, at the cost of a 2.4% reduction in protein production per km2 of grasslands. Furthermore, we identify an important role of national institutions in making these policies effective: Countries with better national institutional quality have larger policy impacts on bird species richness.
'Securing the commons' (2022-)
(with Jessica Meyer and Philippe Delacote)
Since the 1980s, policies have been implemented to secure property rights over hundreds of millions of hectares of land claimed as common property, including land found in protected areas. Such policies are hypothesized to be effective in improving the well-being of resource users when they are less dependent on resources for generating incomes and reside in communities with robust institutions for managing the commons. We first develop a theoretical model to better understand how securing the commons might influence well-being via changes in users’ labour allocation and local institutions. Next, we construct a household panel dataset and apply a differences-in-differences framework to evaluate the well-being and forest impacts of Malawi’s Improved Forest Management for Sustainable Livelihoods Programme (IFMSLP). Our results suggest that the IFMSLP decreased household well-being but had little or no effect on deforestation. Supplementary empirical
analysis supports the theory, that the programme reduced well-being among households who were resource dependent and lived in communities lacking pre-existing institutions for managing, and excluding outsiders from, the commons.
‘The heterogeneous impacts of drought intensity on crop yields in a warming world’ (2021-)
(with Dalia Fadly and Francisco Fontes)
Freshwater is a critical input to agricultural production, the biggest user of water globally. Yet, water scarcity threatens to constrain the future expansion of food supplies. With global warming, droughts are projected to be more frequent, intense, and longer lasting. Addressing water scarcity in the agricultural sector has historically focused on expanding water supply via the building and expansion of irrigation systems. The expansion of irrigation in water-stressed, drought-prone cultivated areas is potentially an effective and sustainable adaptive measure to maintain, or even increase, productivity. Previous research on the benefits of irrigation for productivity and drought mitigation has been conducted at a relatively aggregate level, masking the extent of spatial heterogeneity in irrigation’s realised or potential benefits. We exploit spatial heterogeneity in district-level data collected in India between 1966–2011 to empirically evaluate the extent to which the expansion of irrigation under India’s Interlinking Rivers (ILR) mega project is likely to mitigate the impacts of drought intensity on rice and millet yields. We first show that for both crops there is large spatial heterogeneity in the impacts of drought intensity on yields and that the extent of variation is increasing with greater drought intensity. Negative yield impacts due to higher temperature are offset by greater irrigation coverage, particularly when drought is severe. However, targeted districts in the Peninsular component of the ILR have estimated lower impacts when irrigation is expanded than districts located in the Himalayan component.
'Biodiversity-food trade-offs when agricultural land is spared from production' (2014-2024)
[working paper, version April 2023, forthcoming American Journal of Agricultural Economics]
(with Ben Groom, Lorenzo Sileci and Steve Langton)
Biodiversity conservation in agricultural landscapes, the world’s predominant land use, could involve sparing, or setting aside, agricultural land from production, implying biodiversity-food trade-offs. Employing bird species and agricultural data in two panel datasets, we evaluate the extent of set-aside’s trade-offs in England between 1992 and 2007. Mixed biodiversity outcomes are reflected in a marginal effect, of a
100ha increase in set-aside, associated with a 1-2% increase in species abundance and richness, no impact on Shannon-Wiener diversity and a 0.03 standard deviation fall in phylogenetic diversity. Lower phylogenetic diversity indicates that populations of less genetically distinct bird species appear when set-aside increases. These effects are discontinuous for abundance and richness, and larger in the long-run than in
the short-run for richness and phylogenetic diversity. Set-aside led, on average, to a 7-9% fall in cereal land. In turn, this led to an up to 2% decline in cereal output. A yield increase of 5-10% is likely due to the setting aside of mostly marginal land. Biodiversity-food trade-offs in agricultural landscapes could be minimised with a carefully-targeted set-aside policy, based on clearly defined biodiversity goals, and in
settings where there is still scope for intensification.
(with Ben Groom and Lorenzo Sileci)
International initiatives for reducing carbon emissions from deforestation and forest degradation (REDD+) could make critical, cost-effective contributions to tropical countries’ nationally determined contributions (NDCs). Norway, a key donor of such initiatives, had a REDD+ partnership with Indonesia, offering results-based payments in exchange for emissions reductions calculated against a historical baseline. Central to this partnership was an area-based moratorium on new oil palm, timber, and logging concessions in primary and peatland forests. We evaluate the effectiveness of the moratorium between 2011 and 2018 by applying a matched triple difference strategy to a unique panel dataset. Treated dryland forest inside moratorium areas retained, at most, an average of 0.65% higher forest cover compared to untreated dryland forest outside the moratorium. By contrast, carbon-rich peatland forest was unaffected by the moratorium. Cumulative avoided dryland deforestation from 2011 until 2018 translates into 67.8 million to 86.9 million tons of emissions reductions, implying an effective carbon price below Norway’s US$5 per ton price. Based on Norway’s price, our estimated cumulative emissions reductions are equivalent to a payment of US$339 million to US$434.5 million. Annually, our estimates suggest a 3 to 4% contribution to Indonesia’s NDC commitment of a 29% emissions reduction by 2030. Despite the Indonesia–Norway partnership ending in 2021, reducing emissions from deforestation remains critical for meeting this commitment. Future area-based REDD+ initiatives could build on the moratorium’s outcomes by reforming its incentives and institutional arrangements, particularly in peatland forest areas.
Related commentary: 'Halting deforestation by 2030 – lessons from Indonesia?'