Tipping Points: Not Something We Want to See With Our Climate

tip-ping point: “the point at which a series of small changes or incidents becomes significant enough to cause a larger, more important change.”

A recent article published in Nature last week raises concerns about a number of dire consequences our planet could be facing if we continue our present course. The authors point out that localized ecosystems are known to change abruptly and irreversibly when pushed to critical thresholds, and that global ecosystems might respond in a similar way. We might be headed toward a planetary-scale tipping point as a direct result of our human influence on climate.

The combination of climate change, loss of natural habitat and an increasing global population are changing our planet in ways never before seen. The authors believe these factors will have a greater impact than any of the natural influences on climate that led to previous mass extinctions Earth has experienced. Here, principal author Anthony Barnosky, professor of integrative biology at the University of California, Berkeley discusses what perils we may be facing.

The Nature study falls on the heels of an article published in Scientific American less than two weeks earlier highlighting some of the tipping points our planet is potentially facing.  The Scientific American article is an excerpt from a new book written by Fred Gunerl called “The Fate of the Species.” In it, he points out the real concern: that one tipping point may lead to another, and then another, in a cascading effect.

Gunerl argues that Earth’s climate is a “dynamical system,” which is a fancy way of saying that our planet’s climate has mathematical properties which describe a system that will tend to change quickly, and thus will be hard to predict far in advance. So suffice to say, Gunerl’s book depicts a doom-and-gloom possible worst-case scenario. And just like what happened with Charles Dickens’s Ghost of Christmas Yet To Come in “A Christmas Carol,” we had better hope that we have the same opportunity as Scrooge did to make some necessary changes and avoid a catastrophic fate.

Gunerl refers to a scientist by the name of Tim Lenton from the University of East Anglia in England who has been applying the mathematics of dynamical systems to Earth’s climate and has come up with nine possible tipping points that our planet may have to contend with, all regional rather than global but all potentially impacting the others.

Here are the nine potential tipping points as outlined in an article from The Daily Green published in 2008: (Reference: http://www.thedailygreen.com/environmental-news/latest/tipping-points-47020502#ixzz1xWHTiAcE)

  1. The Indian summer monsoon, which is needed to sustain crops, could collapse anytime as land-to-ocean pressure gradients change with pollution and warming patterns. That could lead to an “erratic” fluctuation that would “chaotically change between an active and a weak phase.” This is considered an “intermediately sensitive” tipping point with large uncertainty.
  2. Arctic sea ice could disappear completely in summer within a decade or so, as the open water absorbs more heat from the sun than is reflected by white ice. This is considered a “highly sensitive” tipping point with low uncertainty.
  3. The Sahara and Sahel in Africa could change dramatically, becoming either far more dry or far more wet, as ocean temperature and vegetation-climate feedbacks change within a decade or so. This is considered an “intermediately sensitive” tipping point with large uncertainty.
  4. The Amazon rainforest could die back significantly within 50 years due to a combination of deforestation and global warming, which could trigger a 30% decrease in rainfall. This is considered an “intermediately sensitive” tipping point with large uncertainty.
  5. The Boreal Forest, which rings the northern latitudes and provides habitat for migratory bird species and other wildlife, could die back within 50 years as trees succumb to summer heat stress, increased diseases and other threats. This is considered an “intermediately sensitive” tipping point with large uncertainty.
  6. the Atlantic thermohaline circulation, which ensures the Gulf Stream warmth reaches Europe, could collapse within 100 years as warming of the oceans alters water density and disrupts the global circulation of the seas. This is considered a “lowly sensitive” tipping point, with intermediate uncertainty.
  7. The El Nino Southern Oscillation, which refers to patterns of warming and cooling in the Pacific Ocean that affect weather worldwide, could within 100 years change to a persistent warm or cool pattern, or change so that warm El Nino patterns are more intense, leading to more intense droughts in some areas, and likelihood of flooding elsewhere. This is considered an “intermediately sensitive” tipping point with large uncertainty.
  8. The Greenland ice sheet could decay within 300 years as cycles of degradation and regrowth tip toward melting within 300 years or more. This could lead to a rise in sea levels of more than 20 feet. This is considered a “highly sensitive” tipping point with low uncertainty.
  9. The West Antarctic ice sheet could collapse within 300 years, leading to a sea level rise of as much as 15 feet worldwide. This is considered an “intermediately sensitive” tipping point with large uncertainty.

A lot of what-ifs here, but food for thought nonetheless. As Lenton has previously stated, “Society must not be lulled into a false sense of security by smooth projections of global change.”

One thing is for certain: our species needs to heed the warning signs our planet is showing us and act on them before it’s too late. If not, then these projections are moot because the tipping point has already taken place.


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