Climate

In the face of a massive financing gap for climate-change mitigation and adaptation in developing countries, everyone accepts the need for more "creative" measures to unlock and redirect private capital. But proposals like carbon credits must be understood merely as stepping stones, rather than as lasting solutions.

A lot of today’s widespread confusion about climate change—some of it unwitting, some of it deliberately cultivated—stems from the critical miscommunication of two little words: risk and uncertainty. To most of the public, risk means a danger that must be addressed, whereas uncertainty means a lack of clarity about whether there is any meaningful danger at all. To scientists and economists like myself, uncertainty has a starkly different meaning. It is worse than risk; it indicates the possible range of just how bad a (very real) danger will be.

California is finally poised to lift parking requirements across the state. Here’s why that would be a huge win for the climate.

Moral hazards are ubiquitous. Green ones typically involve technological fixes: Environmentalists often see ‘technofixes’ as morally fraught because they absolve actors from taking more difficult steps toward systemic solutions. Carbon removal and especially solar geoengineering are only the latest example of such technologies. We here explore green moral hazards throughout American history. We argue that dismissing (solar) geoengineering on moral hazard grounds is often unproductive.

Climate change is beset with unpleasant surprises. Yields of maize (corn), wheat, rice and soya beans all fall precipitously when temperatures exceed certain thresholds — for example, 29 °C for maize. These four staple crops together account for 75% of the calories consumed by humans, so the non-linear temperature dependence of their yields calls for rapid action to avoid the tipping points, either by limiting the carbon dioxide emissions that are warming the planet or by relocating crop fields on a vast scale — probably both.

We exploit regional variations in exposure to heat stress to study if physical climate risk is priced in municipal and corporate bonds as well as in equity markets. We find that local exposure to damages related to heat stress equaling 1% of GDP is associated with municipal bond yield spreads that are higher by around 15 basis points per annum (bps), the effect being larger for longer-term, revenue-only and lower-rated bonds, and arising mainly from the expected increase in energy expenditures and decrease in labor productivity.

Introduction for Special Issue in Honor of Martin Weitzman.

A climate catastrophe can be avoided, but only with a rapid and sustained investment in companies and projects that reduce greenhouse gas emissions. To the surprise of many, this has already begun. Investors are abandoning fossil-fuel companies and other polluting industries and financing businesses offering climate solutions. Rising risks, evolving social norms, government policies, and technological innovation are all accelerating this movement of capital.

While no legislation is perfect, the US Inflation Reduction Act of 2022 will be a game changer for the transition to clean-energy sources, both in America and around the world. By doubling down on forward-looking industrial policy, the US is suddenly poised to give Europe, China, and others a run for their money.