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Nature's not as resilient as we like to think, warns Irish expert

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'More than 4,600 field studies fed into the project that investigated animals, plants and ecosystems from all over the world, including Ireland.' (stock photo)

'More than 4,600 field studies fed into the project that investigated animals, plants and ecosystems from all over the world, including Ireland.' (stock photo)

'More than 4,600 field studies fed into the project that investigated animals, plants and ecosystems from all over the world, including Ireland.' (stock photo)

Nature is not as resilient as policymakers like to think, an Irish scientist involved in the world's biggest ever review of field studies on the subject has warned.

The review found that setting 'tipping points', or thresholds up to which nature can survive exploitation, pollution and other man-made changes, gives a false picture of how nature is coping.

"Pretty much all environmental policy is based on the idea that there is a comfort zone where we can keep pushing nature - and only if we push it to a tipping point will it fall off a cliff," Dr Ian Donohue, a zoologist at Trinity College Dublin, said.

"The truth is we're walking slowly down the cliff every day," he added.

More than 4,600 field studies fed into the project that investigated animals, plants and ecosystems from all over the world, including Ireland.

"The results were the same for biodiversity loss, deforestation, acidification of the seas, and all kinds of biological processes," Dr Donohue said.

"What we found was that it was impossible to pinpoint a threshold in virtually all the studies or to predict when it might be met.

"So we need to stop talking about 'tipping points' and the idea that ecosystems can withstand a certain amount of damage before any real harm is done - all that does it allow for a 'business as usual' attitude and the idea that we don't have to worry until a certain point. We need to see all damage as damaging."

One example is the decline of the sparrow, whose numbers have plummeted, but the bird's drop in numbers is categorised as of 'least concern'.

"We've lost 90pc of our sparrows in the last 30 years, but because they haven't hit the point beyond which there'll be a catastrophe for the species, we're not responding," Dr Donohue said.

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"But when you look at those figures again, 90pc gone in 30 years, you realise that relying on thresholds is not the way to safeguard a species."

Another example is tree felling and burning in the Amazon rainforest, which has led many scientists to try to predict the point at which the forests will be unable to recover.

"We're not saying don't measure and record what's happening. It's essential to have that information," Dr Donohue added.

"But what we are saying is that it's not very helpful to try to work out from those measurements when the point of no return will happen because what the field studies show is that it's almost impossible to do that with any accuracy. Meanwhile, it's a distraction from the fact that the incremental damage happening right now is the problem."

An international team of scientists carried out the analysis under the lead of Professor Helmut Hillebrand of the University of Oldenburg in Germany and their results have just been published in the journal Nature, Ecology and Evolution.

Dr Donohue said the team were taking their findings to international agencies, including the United Nations, urging a change of mindset about environmental protection.

"The problem is that the concept of ecological resilience and 'safe operating spaces' is built into most policies, when that's a flawed approach.

"We're recommending a much more conservative approach and a recognition that damage done to ecosystems today is what must concern us - and not a point in the future."

Climate change was an exception, he stressed, as it was governed by atmospheric physics. "It's very clear there's a tipping point at about two degrees of warming and we're getting close to it. But how biological processes will respond to that, we don't know - and we shouldn't wait to find out."


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