The term "unprecedented" has become increasingly common in descriptions of extreme weather events linked to the climate crisis, prompting questions about how society perceives and responds to such phenomena. Recent data shows an escalation in events described as “unprecedented,” including record-breaking heatwaves, droughts, rainfall, and wildfires worldwide. Despite the frequency of the term, the actual severity of these events continues to surpass previous records, indicating a rapidly changing climate landscape.

In the United Kingdom, for example, the summer of 2023 marked the hottest on record, surpassing the previous high set just one year prior. Around the world, weather patterns are reflecting these extremes, driven in part by the current El Niño event, which is also being characterized as unprecedented in its intensity.

However, research suggests that public perception of such extremes may be shifting. A study analyzing over two billion weather-related social media posts found that although temperatures continue to break historical records, individuals’ subjective judgments about what is remarkable evolve as they become accustomed to recent conditions. This phenomenon, known as “shifting baseline syndrome,” means that people’s sense of normalcy adjusts based on recent experience rather than long-term historical context. Originally identified in fisheries science to describe declining standards for fish populations, this concept applies broadly to environmental degradation and climate change.

Importantly, the study also revealed that while repeated exposure to extreme temperatures may reduce their perceived extraordinariness, the negative emotional response does not diminish. People increasingly recognize the discomfort and risks associated with climate extremes, even as the events feel less unusual. This suggests that growing familiarity with such events can lead to a desensitization of their novelty without reducing concern.

The metaphor of the boiling frog is often invoked in discussions about climate change, warning that gradual increases in temperature may go unnoticed until it is too late to act. Contrary to this parable, experts note that most animals, including frogs, will respond to rising danger by attempting to escape once a critical threshold is crossed. The pressing question, therefore, is whether human societies can similarly respond decisively to escalating climate threats.

Retaining the precise meaning of terms like “unprecedented” is seen as vital for recognizing the unprecedented severity of the current climate emergency. Overuse risks normalizing what should be seen as exceptional and alarming, potentially dulling the urgency necessary for meaningful action. As extreme events continue to occur with greater frequency, clear communication about their novelty and significance remains a critical component in motivating public and policy responses to the ongoing climate crisis.