Climate models often miss the pace of range shifts

A new global analysis compared model predictions with observed range shifts from more than 3,500 terrestrial and marine species. The study examined almost ten thousand documented latitudinal range shifts collected from monitoring efforts around the globe. By pairing these observations with finely tuned climatic niche models that matched the timing and geography of each study, the researchers were able to directly test how well climate-based forecasts align with observed biodiversity redistribution.

The results showed that climatic niche models generally predicted the correct direction of movement. Species were often projected, and observed, to shift poleward as temperatures warmed. This directional agreement was stronger in marine systems, where about 76% of modeled and observed shifts aligned, compared to 56% on land. Marine species likely track climate more closely because ocean environments are more continuous and less fragmented than terrestrial landscapes.

However, the models consistently underestimated how quickly species were moving. In cases where predictions and observations pointed in the same direction, documented range shifts were nearly four times faster than modeled shifts on average. Observed shifts exceeded modeled expectations in 62% of aligned cases, suggesting that many species are redistributing more rapidly than climate-only models anticipate.

The study also identified several factors that improved agreement between predictions and observations. Longer-term studies tended to produce better matches, likely because they smooth out short-term climate variability and reveal clearer long-term trends. On land, higher landscape connectivity reduced mismatches between modeled and observed movements.

Species in well-connected habitats were more likely to track shifting climates in ways that matched model expectations. In contrast, fragmented landscapes increased the likelihood that species responses would diverge from predictions.

Species traits also mattered. Mobile terrestrial organisms such as birds and insects often moved farther than predicted, while sessile organisms like plants showed smaller mismatches. The authors suggest that behavior, dispersal ability, microclimate refuges, and barriers to movement all shape how species respond to climate change beyond what broad climatic models can capture.

The findings highlight an important conservation challenge: climate adaptation strategies increasingly rely on forecasts of future species distributions, but this study shows that species responses are often more dynamic and less predictable than expected. Conservation plans based solely on climate suitability models may underestimate how rapidly species can redistribute when movement pathways remain open.

At the same time, fragmented landscapes can prevent species from tracking suitable conditions at all. Protecting and restoring connected habitats across broad geographic gradients may therefore be one of the most effective ways to support biodiversity under climate change, while also improving the reliability of future ecological forecasts.

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