Climate Matters: Confidence in a changing climate
Climatologists are aware of how the climate is changing and are growing more confident in what we can attribute these changes to. The Intergovernmental Panel on Climate Change (IPCC) now says that human influence on the climate is "unequivocal" and evidence for this has only grown in recent years. While it's clear that human activity has led to variations in the climate pattern the connection still only extends so far. For some weather events, researchers are much more confident that climate change is a factor than others.
When most hear about climate change they first think of warming temperatures, and that's not by chance. We are most confident that extreme temperatures, both hot and cold, are a hallmark of the shifting climate. Temperature swings are observed more often while the base average global temperature is steadily rising. This has been a particularly notable phenomenon, but others can also be tied to climate change.
Going down the spectrum of confidence, climatologists are also becoming more confident that a changing climate is driving more extreme precipitation events. This is connected to those warmer temperatures, as warmer air can hold more moisture overall. Next, with somewhat less confidence but still good research for support, the shifting climate also appears to be responsible for more intense droughts, despite the increasing precipitation just mentioned. These phenomena are actually interlinked; as short bursts of heavier rain are increasing this extends the stretches of drought in between.
It is less certain how climate change is affecting specific weather events like severe or tropical storms. These individual instances of damaging severe storms or disastrous tropical systems cannot all be explained by warmer temperatures or more moisture.
Research continues to increase the support for human influence on a changing climate in many ways while there is still more to learn in other areas. Extreme temperatures are the most certain sign of the new climate regime but heavier rain events and drought are also responding to the shifts. The links between climate and day-to-day weather will only grow as research on both fronts continues.
