Wgi Quotes

Today, TV weather presenters have morphed into climate and weather presenters, blaming a “broken climate” for many of the severe weather events that they cover. Indeed, it has become de rigueur for the media, politicians, and even some scientists to implicate human influences as the cause of heat waves, droughts, floods, storms, and whatever else the public fears. It’s a pretty easy sell: the on-the-scene reporting is powerful—and often moving—and our poor memories of past events can make “unprecedented” quite convincing. But the science tells a different story. Observations extending back over a century indicate that most types of extreme weather events don’t show any significant change—and some such events have actually become less common or severe—even as human influences on the climate grow. In general, there are high levels of uncertainty involved in detecting trends in extreme weather. Here are some (perhaps surprising) summary statements from the IPCC’s AR5 WGI report, indicating what we know (or don’t know) about a few such trends: •​“. . . low confidence regarding the sign of trend in the magnitude and/or frequency of floods on a global scale.”1 •​“. . . low confidence in a global-scale observed trend in drought or dryness (lack of rainfall) since the middle of the 20th century . . .”2 •​“. . . low confidence in trends in small-scale severe weather phenomena such as hail and thunderstorms . . .”3 •​“. . . confidence in large scale changes in the intensity of extreme extratropical cyclones [storms] since 1900 is low.”4