Data published in the journal Geophysical Research Letters shows that the number and intensity of hurricanes and tropical storms have not generally increased over the past 30 years. Likewise, the Intergovernmental Panel on Climate Change has reported: "There is low confidence in any observed long-term (i.e., 40 years or more) increases in tropical cyclone activity (i.e., intensity, frequency, duration), after accounting for past changes in observing capabilities."