Global tipping point not backed by science: Study

February 28, 2013

A group of international ecological scientists led by the University of Adelaide have rejected a doomsday-like scenario of sudden, irreversible change to the Earth's ecology.

In a paper published today in the journal Trends in Ecology and Evolution, the scientists from Australia, US and UK argue that global-scale ecological tipping points are unlikely and that ecological change over large areas seem to follow a more gradual, smooth pattern.

This opposes recent efforts to define 'planetary tipping points' ‒ critical levels of biodiversity loss or land-use change that would have global effect ‒ with important implications for science and policy-makers.

"This is good news because it says that we might avoid the doom-and-gloom scenario of abrupt, irreversible change," says Professor Barry Brook, lead author of the paper and Director of Climate Science at the University of Adelaide. "A focus on planetary tipping points may both distract from the vast ecological transformations that have already occurred, and lead to unjustified fatalism about the catastrophic effects of tipping points.

"An emphasis on a point of no return is not particularly helpful for bringing about the conservation action we need. We must continue to seek to reduce our impacts on the global ecology without undue attention on trying to avoid arbitrary thresholds."

A tipping point occurs when an ecosystem attribute such as species abundance or carbon sequestration responds rapidly and possibly irreversibly to a human pressure like land-use change or climate change.

Many local and regional-level ecosystems, such as lakes and grasslands, are known to behave this way. A planetary tipping point, the authors suggest, could theoretically occur if ecosystems across Earth respond in similar ways to the same human pressures, or if there are strong connections between continents that allow for rapid diffusion of impacts across the planet.

"These criteria, however, are very unlikely to be met in the real world," says Professor Brook. "First, ecosystems on different continents are not strongly connected. Second, the responses of ecosystems to human pressures like climate change or land-use change depend on local circumstances and will therefore differ between localities."

The scientists examined four principal drivers of terrestrial ecosystem change ‒ climate change, land-use change, habitat fragmentation and biodiversity loss ‒ and found they were unlikely to induce global tipping points.

Co-author Associate Professor Erle Ellis, University of Maryland, Baltimore County, says: "As much as four fifths of the biosphere is today characterised by ecosystems that locally, over centuries and millennia, have undergone human-driven regime shifts of one or more kinds. Recognising this reality and seeking appropriate conservation efforts at local and regional levels might be a more fruitful way forward for ecology and global change science."
-end-


University of Adelaide

Related Climate Change Articles from Brightsurf:

Are climate scientists being too cautious when linking extreme weather to climate change?
Climate science has focused on avoiding false alarms when linking extreme events to climate change.

Mysterious climate change
New research findings underline the crucial role that sea ice throughout the Southern Ocean played for atmospheric CO2 in times of rapid climate change in the past.

Mapping the path of climate change
Predicting a major transition, such as climate change, is extremely difficult, but the probabilistic framework developed by the authors is the first step in identifying the path between a shift in two environmental states.

Small change for climate change: Time to increase research funding to save the world
A new study shows that there is a huge disproportion in the level of funding for social science research into the greatest challenge in combating global warming -- how to get individuals and societies to overcome ingrained human habits to make the changes necessary to mitigate climate change.

Sub-national 'climate clubs' could offer key to combating climate change
'Climate clubs' offering membership for sub-national states, in addition to just countries, could speed up progress towards a globally harmonized climate change policy, which in turn offers a way to achieve stronger climate policies in all countries.

Review of Chinese atmospheric science research over the past 70 years: Climate and climate change
Over the past 70 years since the foundation of the People's Republic of China, Chinese scientists have made great contributions to various fields in the research of atmospheric sciences, which attracted worldwide attention.

A CERN for climate change
In a Perspective article appearing in this week's Proceedings of the National Academy of Sciences, Tim Palmer (Oxford University), and Bjorn Stevens (Max Planck Society), critically reflect on the present state of Earth system modelling.

Fairy-wrens change breeding habits to cope with climate change
Warmer temperatures linked to climate change are having a big impact on the breeding habits of one of Australia's most recognisable bird species, according to researchers at The Australian National University (ANU).

Believing in climate change doesn't mean you are preparing for climate change, study finds
Notre Dame researchers found that although coastal homeowners may perceive a worsening of climate change-related hazards, these attitudes are largely unrelated to a homeowner's expectations of actual home damage.

Older forests resist change -- climate change, that is
Older forests in eastern North America are less vulnerable to climate change than younger forests, particularly for carbon storage, timber production, and biodiversity, new research finds.

Read More: Climate Change News and Climate Change Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.