What is the impact of modern transportation technology on long-run economic change in poor countries with high trade costs?  Rail construction in colonial Sub-Saharan Africa provides a natural experiment: 90% of African rail-road lines were built before independence, in a context where...

Expansion in mobile phone coverage has improved access to information throughout the developing world, particularly within sub-Saharan Africa.  The existing evidence suggests that information technology has improved market efficiency and reduced consumer prices for certain commodities.  There...

We report the short-term results from a randomized evaluation of a mobile phone literacy and numeracy program (Project ABC) in Niger, in which adult literacy students learned how to use mobile phones as part of a literacy and numeracy class.  Students in ABC villages showed substantial gains in...

Traditionally, the scholarly journal market operates so that research institutions are charged high prices and the wider public is often excluded altogether, while authors can usually publish for free and commercial publishers enjoy high profits.  Two forms of open access regulation can...

A classroom model of global warming, fossil fuel depletion and the optimal carbon tax is formulated and calibrated. It features iso-elastic fossil fuel demand, stock-dependent fossil fuel extraction costs, an exogenous interest rate and no decay of the atmospheric stock of carbon. The optimal...

The optimal reaction to a pending climate catastrophe is to accumulate capital to be better prepared for the disaster and levy a carbon tax to reduce the risk of the hazard by curbing global warming. The optimal carbon tax consists of the present value of marginal damages, the non-marginal...

Optimal climate policy should act in a precautionary fashion to deal with tipping points that occur at some future random moment. The optimal carbon tax should include an additional component on top of the conventional present discounted value of marginal global warming damages. This component...

We propose a simple structural model of the upstream sector in the oil and gas industry to study the determinants of costs with a focus on its relationship with the price of oil.  We use the real oil price, data on global drilling activity and costs of drilling to estimate a three-dimensional...

The global response to a catastrophic shock to productivity which becomes more imminent with global warming is to have carbon taxes to curb the risk of a calamity and to accumulate precautionary capital to facilitate smoothing of consumption.  Our multi-region model of growth and climate change...

In partial equilibrium a rapidly rising carbon tax encourages oil producers to extract fossil fuels more quickly, giving rise to the Green Paradox. General equilibrium analysis for a closed economy shows that a rapidly rising carbon tax negatively affects the interest rate, which tends to weaken...