Extreme weather events, by definition rare, have always demonstrated the climatic extremes our planet can endure, including ferocious storms, severe heatwaves, and intense cold snaps. However, with the rapid warming of Earth’s climate primarily due to the burning of fossil fuels, the spectrum of possible weather conditions—including extreme weather events—is expanding and altering. This alteration poses significant challenges to how we understand, predict, and adapt to these changes.
Traditionally, climate has been defined by scientists as the distribution of weather events observed over a significant period—usually spanning decades. This method allows for the construction of statistical measures like average temperatures and rainfall, providing a snapshot of what to expect weather-wise in a given area. Meteorologists and climate scientists have customarily used a 30-year interval to define these climate periods, updating their findings every ten years. The most recent period, 1991-2020, illustrates a stark increase in global temperatures, indicative of ongoing climate change.
The critical issue with this traditional method is its decreasing relevance in a rapidly warming world. For instance, comparing atmospheric conditions from the early 1990s to those of the 2020s, we see that extreme weather events are occurring within a markedly different global climate scenario. This includes significantly warmer northerly winds in northwest Europe, a direct result of the Arctic warming nearly four times faster than the global average. Therefore, data from three decades ago may no longer accurately represent current or future climatic possibilities.
Furthermore, our changing climate suggests that we may not have yet experienced the full range of extremes that our increasingly warm atmosphere and oceans can generate. Under stable climatic conditions, scientists could rely on historical data spanning multiple decades to predict and understand potential extreme weather scenarios. However, in our current state of rapid climate change, we find ourselves with only a few years’ worth of data, insufficient for capturing the full array of possible extreme weather events.
The unpredictability is compounded by the fact that certain extreme weather events require what meteorologists refer to as a “perfect storm” of conditions. For example, record-breaking heat in the UK necessitates the confluence of several atmospheric elements—like air masses moving north from Africa and stable, dry conditions. These specific setups are increasingly likely in our changing climate, yet they remain intrinsically rare, making preparation and prediction challenging.
Recent instances, such as the unprecedented heatwave across the Pacific Northwest in 2021 and temperatures soaring past 40°C in the UK in 2022, underscore the new reality of more frequent and intense extremes. These events exceed previous records by significant margins, illustrating that the true impact of global warming becomes apparent only over several decades.
To grasp the potential of future extreme weather events, scientists employ ensemble forecasting—a method involving multiple runs of weather models to predict a range of possible outcomes. This approach was notably used before the UK’s 2022 heatwave, revealing possible temperatures that had previously been unthinkable. While some predicted extremes may not materialize immediately, their mere possibility in model forecasts should serve as a stark warning.
Despite a relatively cool summer in 2024 so far in the UK, the past years have shown that global temperatures and potential extremes are shifting beyond historical observations. This shift suggests that, while we may dodge severe impacts temporarily, the likelihood of facing unprecedented climatic events without adequate preparation increases each year. As such, the need for vigilant monitoring, robust modeling, and proactive adaptation strategies is more crucial than ever to mitigate the risks associated with an evolving climate and the extreme weather events it may bring.