Global patterns of climate displacement and novel climate
This study reveals that while low-emission scenarios primarily drive climate novelty through directional warming, high-emission scenarios cause a dramatic increase in unprecedented climates—rising from 1% to 62% globally by late century—driven largely by seasonal asymmetry and precipitation shifts, thereby exposing the limitations of current climate analogue frameworks and highlighting the urgent need for new paradigms to interpret future climate risks.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Imagine the Earth's climate as a giant, shifting library of weather stories. Every town and city has its own unique "weather biography" written in temperature and rain. For most of human history, if you wanted to know what the weather would be like in a place you'd never visited, you could look at a similar place nearby or check the history books. But as the planet warms, these weather stories are being rewritten. Some places are slowly turning into versions of places that already exist elsewhere—like a town in France slowly starting to feel like a town in Spain. But other places are writing entirely new chapters that have no match in our current library. Scientists call these "novel climates." They are the ultimate plot twists: weather conditions so strange and unprecedented that we have no historical reference point to understand them. This matters because if we can't find a modern equivalent for a future climate, it becomes incredibly hard to plan for the future. How do you build a house, grow food, or protect a city if the weather it will face has never happened before?
This paper, led by John Harrington-Tsunogai, dives deep into this library to see how the stories are changing under different future scenarios. The researchers used powerful computer models to simulate the Earth's climate in the middle and end of this century, comparing them to the weather we've seen between 1995 and 2024. They asked two big questions: How far do places have to "travel" to find a weather match today? And what does the weather look like in the places that have no match at all?
The study found that the answer depends heavily on how much we heat up the planet. If we keep emissions low (a scenario called SSP1-2.6), the changes are relatively gentle. In this future, most places that experience new weather are just getting a bit warmer, like a cozy sweater being replaced by a slightly thicker one. The "novel" weather is rare, affecting only about 1% of the land by the end of the century, and it mostly happens in tricky coastal areas where the ocean makes the weather unique.
However, if we continue on a high-emission path (SSP5-8.5), the story changes dramatically. By the late 21st century, a staggering 62% of the land will experience a climate that has no present-day equivalent. It's as if the library is suddenly filled with books written in a language no one speaks yet. The paper reveals that under this high-heat scenario, the "novelty" isn't just about getting hotter. It's about the weather becoming chaotic and unpredictable in new ways. Instead of just a steady rise in temperature, the new weather is defined by wild swings in seasons and strange changes in rainfall.
The researchers discovered that under high emissions, the "new" weather is often driven by precipitation (rain) and seasonal shifts rather than just a simple temperature increase. For example, in some tropical areas, the heat becomes so extreme that it breaks the historical record, while in other places, the rain patterns become so erratic that they create a climate we've never seen. The study suggests that under high warming, we can't just say "it will be warmer." We have to admit that the very rhythm of the seasons and the way rain falls will change in ways that defy our current understanding.
To visualize this, the team mapped out where these "weather travelers" are going. In low-emission futures, the journey is short; a town might just need to look a few hundred kilometers away to find its future self. But in high-emission futures, the journey is massive. Some places, like parts of the Amazon, would have to travel over 17,000 kilometers to find a climate match today—essentially jumping to the other side of the globe. Meanwhile, some regions like Greenland and Antarctica surprisingly keep their familiar weather, acting as the only stable anchors in a shifting world.
The paper concludes that as we push the planet toward higher temperatures, we are moving from a world where climate change is a simple shift in temperature to a world of "climate novelty" where the rules of the game change entirely. The authors warn that relying on past experiences to plan for the future will become increasingly difficult. If we choose the high-emission path, we aren't just entering a warmer world; we are entering a world with a completely new set of weather rules, where the seasons and rains behave in ways that have no precedent in human history. This suggests that we need new ways to think about and communicate climate risk, because the old maps no longer show the territory we are heading toward.
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