“This engine is grinding to a halt” - Nature slowing down as climate change gains pace

Ecologists have long assumed that, as global warming accelerates, so do changes in nature. The received wisdom was that as temperatures rise and climatic zones shift, species threatened with extinction will move on and colonise new habitats at an ever-increasing rate, leading to a rapid reshuffling of ecological communities.

But a new study by Queen Mary researchers published in Nature Communications shows this is far from the case – in fact, the opposite is true.

The researchers analysed a massive database of biodiversity surveys, spanning marine, freshwater, and terrestrial ecosystems over the last century. The evidence showed that not only had the "turnover" of species in local habitats not sped up, but instead, it had significantly slowed down.

Dr Emmanuel Nwankwo, lead author of the study, explained: “Nature functions like a self-repairing engine, constantly swapping out old parts for new ones. But we found this engine is now grinding to a halt.”

Species turnover declined by one third

The study focused on the period since the 1970s, a time marked by a documented acceleration in global surface temperatures and environmental shifts. The researchers compared ‘species turnover’ rates—the speed at which species replace each other—before and after this climate acceleration.

Contrary to what they expected – that external climate forces would drive faster change – the data revealed that turnover over one- to five-year periods actually became slower. This slowdown was consistent across diverse environments such as terrestrial bird communities or the seabed.

Professor Axel Rossberg, co-author of the study at Queen Mary University of London, said: “We were surprised how strong the effect is. Turnover rates typically declined by one third.”

New insight into ecosystem dynamics

To explain this counter-intuitive finding, the researchers point to the fundamental way ecosystems organise themselves. The study suggests that the communities analysed are not merely reacting passively to external climate drivers. Instead, they appear to be operating in a state known as the "Multiple Attractors" phase that was predicted by theoretical physicist Guy Bunin in 2017.

In a ‘multiple attractors’ phase, species continuously replace one another due to internal interactions—like in a giant, unending game of rock-paper-scissors—even without environmental changes. The new study now provides strong empirical evidence that this ‘multiple attractors’ phase does exist – and that it actually dominates nature.

“Worrying” sign of degradation

If ecosystems are driven by these intrinsic dynamics, why is the turnover slowing down? The authors argue that the observed deceleration is a side effect of environmental degradation and the shrinking of regional species pools.

In a healthy ‘multiple attractors phase’ ecosystem, a large pool of potential colonisers keeps the revolving door of species turnover moving. However, as human activity degrades habitats and reduces these regional pools, the number of potential colonisers drops. This slows the pace at which species replace one another.

Dr Nwankwo said: “In other research we are seeing clear indications that human impacts cause the slowing of turnover. It is worrying.”

The findings suggest that a lack of change in local species composition should not be mistaken for stability or ecosystem health. Instead, the widespread slowdown may indicate that the internal engines of biodiversity are losing momentum due to the depletion of regional life.