Source: PNAS

Should the public be able to recognize that climate is changing, despite the notorious variability of weather and climate from day to day and year to year? We investigate how the probability of unusually warm seasons has changed in recent decades, with emphasis on summer, when changes are likely to have the greatest practical effects. We show that the odds of an unusually warm season have increased markedly over the past three decades. Also the shape of the temperature anomaly distribution, describing the frequency of occurrence of local temperature anomalies, has broadened, making extreme hot summers much more likely. Read more…