Huge Ecosystems Could Collapse In Less Than 50 Years

Huge Ecosystems Could Collapse In Less Than 50 Years The Amazon (left) may one day look more like the Serengeti (right). worldclassphoto / GTS Productions / shutterstock

We know that ecosystems under stress can reach a point where they rapidly collapse into something very different. The clear water of a pristine lake can turn algae-green in a matter of months. In hot summers, a colourful coral reef can soon become bleached and virtually barren. And if a tropical forest has its canopy significantly reduced by deforestation, the loss of humidity can cause a shift to savanna grassland with few trees.

We know this can happen because such changes have already been widely observed. But our research, now published in the journal Nature Communications, shows that the size of the ecosystem is important. Once a “tipping point” is triggered, large ecosystems could collapse much faster than we had thought possible. It’s a finding that has worrying implications for the functioning of our planet.

We started off by wondering how the size of the ecosystem might affect the time taken for these changes (ecologists call them “regime shifts”) to happen. It seems intuitive to expect large ecosystems to shift more slowly than small ones. If so, would the relationship between shift time and size be the same for lakes, corals, fisheries and forests?

We began by analysing data for about 40 regime shifts that had already been observed by scientists. These ranged in size from very small ponds in North America, through to savanna grassland in Botswana, the Newfoundland fishery and the Black Sea aquatic ecosystem.

Huge Ecosystems Could Collapse In Less Than 50 Years Fish like the beluga once ruled the Black Sea, but their reign ended in an ecological collapse that took just 40 years. alexkoral

We found that larger ecosystems do indeed take longer to collapse than small systems, due to the diffusion of stresses across large distances and time-lags. The relationship does seem to hold across different types of ecosystem: lakes take longer than ponds, forests take longer to collapse than a copse, and so on.

But what really stood out was that larger systems shift relatively faster. A forest that is 100 times bigger than another forest will not take 100 times longer to collapse – it actually collapses much more quickly than that. This is quite a profound finding because it means that large ecosystems that have been around for thousands of years could collapse in less than 50 years. Our mean estimates suggest the Caribbean coral reefs could collapse in only 15 years and the whole Amazon rainforest in just 49 years.

Huge Ecosystems Could Collapse In Less Than 50 Years Real world observations (solid line) predict large ecosystems will collapse relatively faster than predicted by a simple linear relationship (dashed line). Dearing et al, Author provided

What explains this phenomenon? To find out, we ran five computer models that simulated things like predation and herbivory (think: wolves, sheep and grasslands) or social networks (how accents spread through society). The models support the data in that large systems collapse relatively faster than small ones.

However, the models also provide further insight. For example, large ecosystems often have relatively more species and habitats existing as connected compartments, or sub-systems. This enhanced “modularity” actually makes the system more resilient to stress and collapse, rather like the water-tight compartments in a ship prevent it from sinking if the hull is breached.

But paradoxically, the same modularity seems to allow a highly stressed system to unravel more quickly once a collapse starts. And because large systems are relatively more modular, their collapse is relatively faster.

These unravelling effects should add to concerns about the effects of fires on the long-term resilience of the Amazon to climate change, or the rapid spread of recent bush fires in Australia caused by existing fires igniting further fires. The only upside to our finding concerns ecosystems that have already been managed into alternate regimes, such as human-made agricultural landscapes. These now have much less modularity, and thus may experience relatively slow transitions in the face of climate change or other stresses.

The messages are stark. Humanity now needs to prepare for changes in ecosystems that are faster than we previously envisaged through our traditional linear view of the world. Large iconic ecosystems like the Amazon rainforest or the Caribbean coral reefs are likely to collapse over relatively short “human timescales” of years and decades once a tipping point is triggered. Our findings are yet another reason to halt the environmental damage that is pushing ecosystems to their limits.

About The Author

John Dearing, Professor of Physical Geography, University of Southampton; Greg Cooper, Postdoctoral Research Fellow, Centre for Development, Environment and Policy, SOAS, University of London, and Simon Willcock, Senior Lecturer in Environmental Geography, Bangor University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Related Books

Life After Carbon: The Next Global Transformation of Cities

by Peter Plastrik , John Cleveland
1610918495The future of our cities is not what it used to be. The modern-city model that took hold globally in the twentieth century has outlived its usefulness. It cannot solve the problems it helped to create—especially global warming. Fortunately, a new model for urban development is emerging in cities to aggressively tackle the realities of climate change. It transforms the way cities design and use physical space, generate economic wealth, consume and dispose of resources, exploit and sustain the natural ecosystems, and prepare for the future. Available On Amazon

The Sixth Extinction: An Unnatural History

by Elizabeth Kolbert
1250062187Over the last half-billion years, there have been Five mass extinctions, when the diversity of life on earth suddenly and dramatically contracted. Scientists around the world are currently monitoring the sixth extinction, predicted to be the most devastating extinction event since the asteroid impact that wiped out the dinosaurs. This time around, the cataclysm is us. In prose that is at once frank, entertaining, and deeply informed, New Yorker writer Elizabeth Kolbert tells us why and how human beings have altered life on the planet in a way no species has before. Interweaving research in half a dozen disciplines, descriptions of the fascinating species that have already been lost, and the history of extinction as a concept, Kolbert provides a moving and comprehensive account of the disappearances occurring before our very eyes. She shows that the sixth extinction is likely to be mankind's most lasting legacy, compelling us to rethink the fundamental question of what it means to be human. Available On Amazon

Climate Wars: The Fight for Survival as the World Overheats

by Gwynne Dyer
1851687181Waves of climate refugees. Dozens of failed states. All-out war. From one of the world’s great geopolitical analysts comes a terrifying glimpse of the strategic realities of the near future, when climate change drives the world’s powers towards the cut-throat politics of survival. Prescient and unflinching, Climate Wars will be one of the most important books of the coming years. Read it and find out what we’re heading for. Available On Amazon

From The Publisher:
Purchases on Amazon go to defray the cost of bringing you InnerSelf.comelf.com, MightyNatural.com, and ClimateImpactNews.com at no cost and without advertisers that track your browsing habits. Even if you click on a link but don't buy these selected products, anything else you buy in that same visit on Amazon pays us a small commission. There is no additional cost to you, so please contribute to the effort. You can also use this link to use to Amazon at any time so you can help support our efforts.

 

enafarzh-CNzh-TWdanltlfifrdeiwhihuiditjakomsnofaplptruesswsvthtrukurvi

follow InnerSelf on

facebook-icontwitter-iconrss-icon

 Get The Latest By Email

{emailcloak=off}

LATEST VIDEOS

Methane Emissions Hit Record Breaking Levels
Methane Emissions Hit Record Breaking Levels
by Josie Garthwaite
Global emissions of methane have reached the highest levels on record, research shows.
kelp forrest 7 12
How The Forests Of The World’s Oceans Contribute To Alleviating The Climate Crisis
by Emma Bryce
Researchers are looking to kelp for help storing carbon dioxide far beneath the surface of the sea.
Tiny Plankton Drive Processes In The Ocean That Capture Twice As Much Carbon As Scientists Thought
Tiny Plankton Drive Processes In The Ocean That Capture Twice As Much Carbon As Scientists Thought
by Ken Buesseler
The ocean plays a major role in the global carbon cycle. The driving force comes from tiny plankton that produce…
Climate Change Threatens Drinking Water Quality Across The Great Lakes
Climate Change Threatens Drinking Water Quality Across The Great Lakes
by Gabriel Filippelli and Joseph D. Ortiz
“Do Not Drink/Do Not Boil” is not what anyone wants to hear about their city’s tap water. But the combined effects of…
Talking About Energy Change Could Break The Climate impasse
Talking About Energy Change Could Break The Climate Impasse
by InnerSelf Staff
Everyone has energy stories, whether they’re about a relative working on an oil rig, a parent teaching a child to turn…
Crops Could Face Double Trouble From Insects And A Warming Climate
Crops Could Face Double Trouble From Insects And A Warming Climate
by Gregg Howe and Nathan Havko
For millennia, insects and the plants they feed on have been engaged in a co-evolutionary battle: to eat or not be…
To Reach Zero Emissions Government Must Address Hurdles Putting People Off Electric Cars
To Reach Zero Emissions Government Must Address Hurdles Putting People Off Electric Cars
by Swapnesh Masrani
Ambitious targets have been set by the UK and Scottish governments to become net-zero carbon economies by 2050 and 2045…
Spring Is Arriving Earlier Across The US, And That's Not Always Good News
Spring Is Arriving Earlier Across The US, And That's Not Always Good News
by Theresa Crimmins
Across much of the United States, a warming climate has advanced the arrival of spring. This year is no exception.

LATEST ARTICLES

Two-thirds Of Glacier Ice In The Himalayas Could Be Lost By 2100
Two-thirds Of Glacier Ice In The Himalayas Could Be Lost By 2100
by Ann Rowan
In the world of glaciology, the year 2007 would go down in history. It was the year a seemingly small error in a major…
Rising Temps Could Kill Millions A Year By Century’s End
Rising Temps Could Kill Millions A Year By Century’s End
by Edward Lempinen
By the end of this century, tens of millions of people could die each year worldwide as a result of temperatures rising…
New Zealand Wants To Build A 100% Renewable Electricity Grid, But Massive Infrastructure Is Not The Best Option
New Zealand Wants To Build A 100% Renewable Electricity Grid, But Massive Infrastructure Is Not The Best Option
by Janet Stephenson
A proposed multibillion-dollar project to build a pumped hydro storage plant could make New Zealand’s electricity grid…
Wind Farms Built On Carbon-rich Peat Bogs Lose Their Ability To Fight Climate Change
Wind Farms Built On Carbon-rich Peat Bogs Lose Their Ability To Fight Climate Change
by Guaduneth Chico et al
Wind power in the UK now accounts for nearly 30% of all electricity production. Land-based wind turbines now produce…
Climate Denial Hasn't Gone Away – Here's How To Spot Arguments For Delaying Climate Action
Climate Denial Hasn't Gone Away – Here's How To Spot Arguments For Delaying Climate Action
by Stuart Capstick
In new research, we have identified what we call 12 “discourses of delay”. These are ways of speaking and writing about…
Routine Gas Flaring Is Wasteful, Polluting And Undermeasured
Routine Gas Flaring Is Wasteful, Polluting And Undermeasured
by Gunnar W. Schade
If you’ve driven through an area where companies extract oil and gas from shale formations, you’ve probably seen flames…
Flight Shaming: How To Spread The Campaign That Made Swedes Give Up Flying For Good
Flight Shaming: How To Spread The Campaign That Made Swedes Give Up Flying For Good
by Avit K Bhowmik
Europe’s major airlines are likely to see their turnover drop by 50% in 2020 as a result of the COVID-19 pandemic,…
Will The Climate Warm As Much As Feared By Some?
Will The Climate Warm As Much As Feared By Some?
by Steven Sherwood et al
We know the climate changes as greenhouse gas concentrations rise, but the exact amount of expected warming remains…