The planet has broken global heat records for three years in a row — a finding that, paradoxically, may raise public concern about global warming but won't change long-term climate forecasts.

First, the good news: Scientists say the run of record-breaking temperatures doesn't mean that we should expect every year to be relentlessly hotter than the last. From year to year, temperatures may cycle from hotter to cooler and back again. The bad news, however, is that without serious cuts in greenhouse gas emissions, the world will get much warmer over the long term. There's widespread consensus that over the course of the 21st century, unchecked global warming will disrupt agriculture, flood cities and drive species to extinction.

Focusing on record-breaking years alone can be misleading. It means throwing away the bulk of your data, said statistical physicist Sidney Redner of the Santa Fe Institute. Looking at systematic long-term trends, he said, "is the more kosher way to do things."