Global temperatures have increased at an unprecedented pace in the past 40 years. This paper finds that increases in temperature have uneven macroeconomic effects, with adverse consequences concentrated in countries with hot climates, such as most low-income countries. In these countries, a rise in temperature lowers per capita output, in both the short and medium term, through a wide array of channels: reduced agricultural output, suppressed productivity of workers exposed to heat, slower investment, and poorer health. In an unmitigated climate change scenario, and under very conservative assumptions, model simulations suggest the projected rise in temperature would imply a loss of around 9 percent of output for a representative low-income country by 2100.

Global temperatures have increased at an unprecedented pace in the past 40 years. This paper finds that increases in temperature have uneven macroeconomic effects, with adverse consequences concentrated in countries with hot climates, such as most low-income countries. In these countries, a rise in temperature lowers per capita output, in both the short and medium term, through a wide array of channels: reduced agricultural output, suppressed productivity of workers exposed to heat, slower investment, and poorer health. In an unmitigated climate change scenario, and under very conservative assumptions, model simulations suggest the projected rise in temperature would imply a loss of around 9 percent of output for a representative low-income country by 2100.

Over the past three decades, the price of machinery and equipment fell dramatically relative to other prices in advanced and emerging market and developing economies. Using crosscountry and sectoral data, we show that the decline in the relative price of tangible tradable capital goods provided a significant impetus to the capital deepening that took place during the same time period. The broad-based decline in the relative price of machinery and equipment, in turn, was driven by the faster productivity growth in the capital goods producing sectors relative to the rest of the economy, and deeper trade integration, which induced domestic producers to lower prices and increase their efficiency. Our findings suggest an additional channel through which rising trade tensions and sluggish productivit y could threaten real investment growth going forward.

Macroeconomic costs of conflict are generally very large, with GDP per capita about 28 percent lower ten years after conflict onset. This is overwhelmingly driven by private consumption, which falls by 25 percent ten years after conflict onset. Conflict is also associated with dramatic declines in official trade, with exports (imports) estimated to be 58 (34) percent lower ten years after conflict onset. The onset of conflict often also induces significant refugee outflows to neighboring non-advanced countries in the short run, and relatively small but very persistent refugee outflows to advanced countries over the long run. Finally, we stress that conflict should be defined in terms of the number of people killed relative to the total population. The traditional definition of conflict—based on the absolute number of deaths—skews the sample toward low-intensity conflicts in large countries, thereby understating the negative effects of conflict from a macroeconomic perspective.

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