Commentary

CAMBRIDGE – America’s presidential election is now just six months away. If history is a reliable guide, the outcome will depend significantly on the economy’s performance between now and November 6, and on Americans’ perception of their economic future under the two candidates.

STOCKHOLM – Particle emissions into Earth’s atmosphere affect both human health and the climate. So we should limit them, right? For health reasons, yes, we should indeed do that; but, paradoxically, limiting such emissions would cause global warming to increase. Why?