“Using information to improve global cooperation: a climate change experiment”, P. Naso, T. Theoduloz, N. Tyack, D. Gelo, M. Sarr, Mare, T. Swanson,CIES Research Paper ; 72, 2021

We run an experiment in five countries with 7,132 participants to study how information on the contribution of others influences contributions to climate change mitigation. Participants receive artificially generated information on the average contribution of others, on the ranking of contributions and endowments of others, and on others’ nationalities. We show that (i) participants from developed countries free ride on the average of others, whereas participants from developing countries follow the lead of the majority; (ii) information on the ranking of contributions increases participants’ contributions as compared to information on the average of others; and (iii) participants dislike to be in the first and last position of the contribution ranking. Our results suggest that a country’s contribution to climate change mitigation can be promoted by using information on the contributions of other countries.

Food security in the long-run: a macroeconomic approach to land use policy“, P. Naso, O. Haznedar, B. Lanz, T. Swanson, CIES Research Paper ; 71, 2021


“The Return of Malthus?  Resource Constraints in an Era of Declining Population Growth”, P. Naso and B. Lanz, T. Swanson, European Economic Review, 128:103499 (September 2020)

Will natural resources comprise an important constraint on economic development in the 21st century? We use a macroeconomic model (MAVA) to demonstrate the precise nature of this problem. First, we employ the model to demonstrate that resource constraints do not substantially limit future economic growth under parametric conditions prevailing in the period 1960–2010. Second, we examine the sorts of changed conditions that are unavoidable in the coming century and demonstrate that declining population growth (and the increased dependency rates this implies) is likely to result in increasingly important resource constraints. Ironically, it is the decline in population growth rates—and not the opposite—that may occasion the return of Malthusian constraints.

“An Introduction to the Economics of Malthusianism” T. Aidt, T. Swanson, European Economic Review, 128:103546 (September 2020)

The economics of Malthusianism is a set of assumptions concerning the way in which population, technology and resource constraints interact. In its earliest form, it made assumptions concerning technology and resource constraints that implied that they were static and fixed, so that the aggregate production function was concave and static, as implied by the existence of a requisite and fixed factor of production. By way of contrast, the assumption concerning population was that it was dynamic, and positively related to any growth in consumption. In this way, the Iron Law of Malthus, as laid out in Thomas Malthus’ famous “Essay on the Principle of Population” published in 1798, was derived from the application of these simple population dynamics to the static nature of the production system – any production surplus that was available for consumption would be dissipated on fertility increases, moving society inexorably toward the economic steady-state. Two hundred years after Malthus’ essay, there remain many unresolved issues to be explored against the backdrop of his theorizing and this special issue takes up three.

The Impact of Environmental Regulation on China’s Spatial Development P. Naso and Y. Huang, T. Swanson, Economics of Transition and Institutional Change, vol. 28(1), pages 161-194, (January 2020)

We examine the relationship between environmental regulation and spatial development in China. Exploiting changes in national pollution standards for three industries, ammonia, paper and cement, we measure the impact of environmental regulation on industry productivity. Our results suggest that national pollution standards do not affect industry productivity, but they reallocate productivity spatially. We show that regulated industries located in developing cities increase their productivity compared to similar industries in other cities. This means that environmental regulation affects the spatial distribution of technology in China and might influence long-term spatial development by reducing geographical disparities.

“Legal pluralism in post-conflict Sierra Leone”, P. Naso, E. Bulte, T. Swanson, European Journal of Political Economy, 61:101819 (January 2020)

We examine the interaction between two legal systems in post-conflict Sierra Leone. To do that, we measure the impact of competition between state and non-state legal authorities on the number of disputes and on the amount of fines charged per dispute. Our results suggest a potential negative externality between regimes for civil disputes that is, an increase in the cost of apprehending a person and a reduction in the amount of fines per dispute collected when two regimes operate in the same village. This indicates that a potential benefit to the local people from multiple competing regimes is a reduction on expected authoritative expropriation.

“Feeding the world, leaving the land : economics of growth, population and resource constraints”, B. Lanz, S. Dietz, T. Swanson, forthcoming Cambridge University Press.


“The expansion of modern agriculture and global biodiversity decline: An integrated assessment”, B. Lanz, S. Dietz, T. Swanson, Ecological Economics 144: 260-277.

The world is banking on a major increase in food production, if the dietary needs and food preferences of an increasing, and increasingly rich, population are to be met. This requires the further expansion of modern agriculture, but modern agriculture rests on a small number of highly productive crops and its expansion has led to a significant loss of global biodiversity. Ecologists have shown that biodiversity loss results in lower plant productivity, while agricultural economists have linked biodiversity loss on farms with increasing variability of crop yields, and sometimes lower mean yields. In this paper we consider the macro-economic consequences of the continued expansion of particular forms of intensive, modern agriculture, with a focus on how the loss of biodiversity affects food production. We employ a quantitative, structurally estimated model of the global economy, which jointly determines economic growth, population and food demand, agricultural innovations and land conversion. We show that even small effects of agricultural expansion on productivity via biodiversity loss might be sufficient to warrant a moratorium on further land conversion.


“Global Population Growth, Technology, and Malthusian Constraints: A Quantitative Growth Theoretic Perspective”, B. Lanz, S. Dietz, T. Swanson, International Economic Review 58(3): 973-1006.

We structurally estimate a two‐sector Schumpeterian growth model with endogenous population and finite land reserves to study the long‐run evolution of global population, technological progress, and the demand for food. The estimated model closely replicates trajectories for world population, GDP, sectoral productivity growth, and crop land area from 1960 to 2010. Projections from 2010 onward show a slowdown of technological progress, and, because it is a key determinant of fertility costs, significant population growth. By 2100, global population reaches 12.4 billion and agricultural production doubles, but the land constraint does not bind because of capital investment and technological progress.

“Global Economic Growth and Agricultural Land Conversion under Uncertain Productivity Improvements in Agriculture”, B. Lanz, S. Dietz, T. Swanson, American Journal of Agricultural Economics 100(2): 545-569.

We study how stochasticity in the evolution of agricultural productivity interacts with economic and population growth at the global level. We use a two-sector Schumpeterian model of growth, in which a manufacturing sector produces the traditional consumption good and an agricultural sector produces food to sustain contemporaneous population. Agriculture demands land as an input, itself treated as a scarce form of capital. In our model both population and sectoral technological progress are endogenously determined, and key technological parameters of the model are structurally estimated using 1960-2010 data on world GDP, population, cropland and technological progress. Introducing random shocks to the evolution of total factor productivity in agriculture, we show that uncertainty optimally requires more land to be converted into agricultural use as a hedge against production shortages, and that it significantly affects both optimal consumption and population trajectories.


BRPP3“Multi-scale simplification of agricultural land:  a review and research agenda on the external costs for global food production”, D. Eaton, S. Dietz, B. Lanz, T. Swanson, J. Tewklsbury, Biodiversity Review Project Paper 3.

Processes of agricultural simplification take place at different spatial scales from the field to the globe. We propose the concept of multi-scale simplification to bring together these linked processes. Whereas it is well documented that agricultural simplification has brought about increases in production on the one hand and environmental harms outside the production system on the other hand, we ask whether multi-scale simplification also imposes external costs on agricultural production itself, due to its effects on vulnerability to pests and disease, pollination and soil fertility.

We review the evidence and propose an economic model compatible with the existence of external costs on production, which can serve as the basis for future empirical research across disciplines. The model proposes several mechanisms, by which maximizing production of the whole food system implies reducing the extent of  agricultural simplification.


BRPP2“Running with the red queen : an integrated assessment of agricultural land expansion and global biodiversity decline”, B. Lanz, S. Dietz, T. Swanson, Biodiversity Review Project Paper 2.

Modern agriculture relies on a small number of highly productive crops and the continued expansion of agricultural land area has led to a significant loss of biodiversity. In this paper we consider the macroeconomic consequences of a continued expansion of modern agriculture from the perspective of agricultural productivity and food production: as the genetic material supporting agriculture declines, pests and pathogens become more likely to adapt to crops and proliferate, increasing crop losses due to biological hazards.
To evaluate the macroeconomic consequences of a reduction in agricultural productivity associated with the expansion of agriculture, we employ a quantitative, structurally estimated model of the global economy in which economic growth, population and food demand, agricultural innovations, and the process of land conversion are jointly determined. We show that even a small impact of global biodiversity on agricultural productivity calls for both a halt in agricultural land conversion and increased agricultural R&D in order to maintain food production associated with population and income growth.

BRPP1“Global population growth, technology, and malthusian constraints : a quantitative growth theoretic perspective”, B. Lanz, S. Dietz, T. Swanson, Biodiversity Review Project Paper 1.

How much further will the global population expand, will we exhaust natural land reserves, and what is the role in this story of economic growth? We study the interactions between global population, technological progress, per-capita income, and agricultural land expansion from 1960 to 2100. We structurally estimate a two-sector Schumpeterian growth model with endogenous fertility and finite natural land reserves, in which a manufacturing sector provides a consumption good and an agricultural sector provides food to sustain contemporaneous population. The model closely replicates 1960-2010 data on world population, GDP, productivity growth and crop land area, and we employ the model to make projections from 2010 to 2100. Results suggests a slowdown of technological progress, and, because it is the main driver of a transition to a regime with low population growth, significant population growth over the whole century. Global population is slightly below 10 billion by 2050, further growing to 12 billion by 2100. As population and per capita income grow, demand for agricultural output almost doubles over the century, but the land constraint does not bind because of capital investment and technological progress. This provides a first integrative view of future population development in the context of modern growth theory, and thus a novel perspective on a key driver of future resource scarcity.