Just for parity, to go along with my recent
sweeping planetary-scale source of happy and hope for the future... I've discovered a source of equally bad news, on a similar scale; we're approaching a State-Shift in Earth's Biosphere, with serious consequences for life as we know it. We're talking "Mass Extinction Event" serious.
A growing consensus of scientists believe human action is driving us toward a planetary state shift, where shifting weather patterns and climate zones, as well as drastic ecological changes, begin to cause a feedback loop which historically ends in mass-extinction events. Global warming, mass die-out of our coral reefs, colony collapse disorder, and the rapidly rising extinction rate of species on Earth are all indicative of this shift.
In the last few decades, scientists have found tipping behaviors in various natural environments, from locale-scale ponds and coral reefs to regional systems like the Sahara desert, which until 5,500 years ago was a fertile grassland, and perhaps even the Amazon basin.
Common to these examples is a type of transformation not described in traditional ideas of nature as existing in a static balance, with change occurring gradually. Instead, the systems seem to be dynamic, ebbing and flowing within a range of biological parameters.
Stress those parameters — with fast-rising temperatures, say, or a burst of nutrients — and systems are capable of sudden, feedback loop-fueled reconfiguration.
According to some researchers, that’s what happened when life’s diversity exploded in an eyeblink 540 million years ago, or much more recently when a glacier-chilled Earth became in a couple thousand years the temperate garden that cradled human civilization.
But while the Cambrian explosion and Holocene warming were sparked by natural, planet-wide changes to ocean chemistry and solar intensity, say Barnosky and colleagues, there’s a new force to consider: 7 billion people who exert a combined influence usually associated with planetary processes.
Human activity now dominates 43 percent of Earth’s land surface and affects twice that area. One-third of all available fresh water is diverted to human use. A full 20 percent of Earth’s net terrestrial primary production, the sheer volume of life produced on land every year, is harvested for human purposes. Extinction rates compare to those recorded during the demise of dinosaurs and average temperatures will likely be higher in 2070 than at any point in human evolution.
Scientists informally call our current geological age the “Anthropocene,” and to Barnosky’s group this means we’re strong enough to tip the planet, radically changing regional climates and ecologies.
"Everything that happened the last time around is happening now, only more of it," said Barnosky of the last ice age’s end and ongoing changes to Earth’s climate and biosphere. "I think the evidence makes it pretty clear that another critical transition or tipping point is very plausible within the next century."
It's not a doomsday theory, but a known facet of Earth's history, and one which a growing body evidence suggests is now approaching us. The difference this time is that it's on a human time-scale, rather than geological one... and Earth's biodiversity still hasn't fully recovered from the Holocene Warming, the state-shift which marked the end of the Ice Age. By some estimates, this could come into effect within our lifetimes or soon thereafter, and what such an event would mean for Earth and the Human species, let alone Human civilization, is entirely unknown.
If you have access to scientific journal Nature (via Universities, Libraries, etc.)
you can check out the original scientific publication here.
Summaries of the publication can also be found here:
http://www.businessinsider.com/scientists-environment-verge-of-disaster-2012-6http://grist.org/climate-energy/were-about-to-push-the-earth-over-the-brink-new-study-finds/
Author
Topic: Things that made you sad today thread. (Read 9778915 times)