The unavoidable disaster coming to our coral reefs

Posted on July 15th, 2012 in ecology,Environment by Robert Miller

If you haven’t read Roger Bradbury’s op-ed piece in the New York Times, published yesterday, this a good time to familiarize yourself with it. Roger is an adjunct professor, specialized in coral reefs and ecological issues at the Crawford School, a public policy branch of the Australian National University. In his article, he raises the issue that to me is suitably alarmist. Our coral reefs, with their rich biodiversity will be gone and it seems unlikely that unless we put an emergency effort into halting the processes that are destroying these gems, including a rapid reduction in atmospheric carbon dioxide, they will vanish, reducing the ocean in those regions to something like it was in the Precambrian era of 500 million years ago when it was rich in algae, jelly fish and very few  fish. The culprits are the ones we already know about—overfishing—acidification of the oceans through the absorption of atmospheric carbon dioxide—and pollution, the latter influence being the hardest to know about  because we don’t have models to predict a large-scale experiment that has never been done. He begins his article by stating that “IT’S past time to tell the truth about the state of the world’s coral reefs, the nurseries of tropical coastal fish stocks. They have become zombie ecosystems, neither dead nor truly alive in any functional sense, and on a trajectory to collapse within a human generation. There will be remnants here and there, but the global coral reef ecosystem — with its storehouse of biodiversity and fisheries supporting millions of the world’s poor — will cease to be.
Bradbury refers to a recent statement that came out of a The International Coral Reef Symposium, in which scientists signed a statement supporting immediate action to prevent an imminent coral reef disaster:
Consensus Statement on Climate Change and Coral Reefs

The international Coral Reef Science Community calls on all governments to ensure the future of coral reefs, through global action to reduce the emissions of carbon dioxide and other greenhouse gases, and via improved local protection of coral reefs. Coral reefs are important ecosystems of ecological, economic and cultural value yet they are in decline worldwide due to human activities. Land-based sources of pollution, sedimentation, overfishing and climate change are the major threats, and all of them are expected to increase in severity.

Changes already observed over the last century:

  • Approximately 25-30% of the world’s coral reefs are already severely degraded by local impacts from land and by over-harvesting.
  • The surface of the world’s oceans has warmed by 0.7°C, resulting in unprecedented coral bleaching and mortality events.
  • The acidity of the ocean’s surface has increased due to increased atmospheric CO2.
  • Sea-level has risen on average by 18cm.

By the end of this century:

  • CO2 emissions at the current rate will warm sea surface temperatures by at least 2-3°C, raise sea-level by as much as 1.7 meters, reduce ocean pH from 8.1 to less than 7.9, and increase storm frequency and/or intensity. This combined change in temperature and ocean chemistry has not occurred since the last reef crisis 55 million years ago.

Other stresses faced by corals and reefs:

  • Coral reef death also occurs because of a set of local problems including excess sedimentation, pollution, habitat destruction, and overfishing.
  • These problems reduce coral growth and vitality, making it more difficult for corals to survive climate changes.

Future impacts on coral reefs:

  • Most corals will face water temperatures above their current tolerance.
  • Most reefs will experience higher acidification, impairing calcification of corals and reef growth.
  • Rising sea levels will be accompanied by disruption of human communities, increased sedimentation impacts and increased levels of wave damage.

Together, this combination of climate-related stressors represents an unprecedented challenge for the future of coral reefs and to the services they provide to people.

Across the globe, these problems cause a loss of reef resources of enormous economic and cultural value. A concerted effort to preserve reefs for the future demands action at global levels, but also will benefit hugely from continued local protection.

The scientific warnings about imminent threats to our environment have gone unheeded, due in large part to the influence of capitalist forces that control the global political agenda. With the threatened destruction of most of our coral reefs within a few generations if not sooner, we are faced with a catastrophe that we may see during our lifetime, one that may usher in a whole new series of rapid changes to livelihoods from the sea and starving populations who now depend on the coral reef system for sustenance.  We tend to study the effects of these global forces degrading coral reefs, but not the rate at which their powers of destruction operate to diminish our future. Rate is everything, but very hard to predict. We are still early in the sixth species extinction, but we are gaining momentum and there is no doubt that this one is appropriately referred to as the anthropogenic species destruction because the offending party is us. Once these processes start, they can’t be stopped and this logic applies as well to the melting of the Greenland Ice and the Polar icecaps, but especially that of Antarctica. If we reduced atmospheric carbon dioxide tomorrow, we would have at least fifty years of reef destruction and global climate change conditions. These changes will be with us no matter what we do, but beyond that period, by reducing emissions and poisoning of the coral reefs, we might stand a chance of eventually seeing them restored. It is of course an issue about whether we have the political will to create a national movement that insists on habitat preservation, though this concept has become far more complex today that it was twenty years ago. The destruction of the global economy fits neatly into creating a national pause in the pursuit of overdue fixes to stabilize our environmental future.

RFM

  • Comments Off on The unavoidable disaster coming to our coral reefs

A picture of the Higgs boson?

Posted on July 8th, 2012 in Science by Robert Miller

Higss boson detection?
(Taken from G. Aad et al, Physical Review Let, 108, 2012). Detection based on decay into two photons causing a bump in the decay rate at 125 GeV (Giga electron Volts)

With the apparent discovery of the Higgs boson (not absolutely certain yet), using the Large Hadron Collider (LHC) located near Geneva Switzerland (but also extending into French territory), particle physicists celebrated their achievement and left no doubt that the largest particle accelerator in the world had proved its worth, by discovering the Higgs boson and validating  the very reason for its construction. The LHC is under the control of CERN, originally derived from the French “Conseil Européen pour la Recherche Nucléaire,” or in its anglicized form, the “European Council for Nuclear Research.” Those associated with this giant collider can properly lay claim not only to the most powerful accelerator in the world, but also display the swagger that comes from a European facility, rather than one residing in the United States. The American Superconducting Super Collider—the largest basic science project in world history at the time— was cancelled by Congress in 1993 as a result of the imminent takeover of Congress by the Newt Gingrich Republicans and their “Contract on America.” This abandoned project lies as a giant hole in Texas, right outside of Dallas. As Congress cancelled the project they had to spend an extra $1 billion, just to seal the hole and shut the project down. It is an underground monument to the end of public support for physicists who had been the darlings of Congress, from the time they built the atomic and hydrogen bombs until they cancelled the Super Collider project very abruptly, throwing some 2000 physicists out of work. Had it been completed, it very likely would have provided the technology to detect the Higgs boson some years ago. Some of the physicists who lost employment when the Super Collider was cancelled,  moved on to Wall Street and produced the mathematical models that continue to provide uncertainty about the stability of Wall Street and its trading practices. But, we digress.

The LHC is a marvel of technology, with two 27 km rings of superconducting magnets, that move particles close to the speed of light in opposite directions in each of two rings of magnets. The superconducting magnets that accelerate the flow of particles (usually protons) are cooled to -271 degrees Centigrade by liquid helium, which circulates within the structure. At certain points along the accelerator path, magnets are used to bring the particles together in opposing streams at positions where detectors are placed to record the high speed collisions and detect various types of particle species that emerge.   As a result of this particle train wreck, multiple particles are generated and separate detectors are used to capture images of the complex decay events.  As a result of the Higgs boson experiment and the many similar studies that will follow, particle physicists are dreaming about a far more complete picture of the structure of the atom, the composition of the universe and the forces that interact to make these structures behave in a rational way when we make reactions in  a test tube, or use them in ordinary, everyday life, expecting consistent reactions and results. If we had solved the atomic structure of the atom first, we probably would never have put anything in a test tube because our assumption would be that nothing simple could possibly work. At the supra-atomic  level things seem quite predictable, but at the sub-atomic level it is a picture of chaos taking place within a massive, largely unoccupied space. The discovery of the Higgs boson may lead to a complete description of the structure of the atom and provide an account of the major forces  that created the universe, including such things as dark matter, though at the moment this is far from certain and no particle physicist would be surprised if additional forces or sub-atomic particles are revealed by future operations of the LHC. Many scientists remain cautious about over-exuberance based on the present results, because if the Higgs boson is for real, one should see evidence for it from several different detectors, as the Higgs boson can decay into several different types of particles.  The results illustrated in the figure were based on the detection of a Higgs boson decaying into two photons. And scientists define these bumps on the basis of the number of standard deviations above the background, hoping to see events that in the range of 3 to 5 standard deviations above the background.  For the next several years, we can expect the results of the LHC to appear on the front pages of our newspapers and occasionally be inserted  above the fold. If one can accept the Standard Model of the atom, for which the Higgs boson may be the last piece of the puzzle to fall into place, why can’t we accept global climate change, for which we do not require a particle accelerator to visualize what is going on around us within our little blue planet?

Physicist Sean Carroll’s website illustrates what one might call a “photograph” of a Higgs boson decay process, illustrated in the accompanying figure. This figure plots the number of events recorded (events/GeV=Giga electron volts) as a function of the mass of the particle (also measured in GeV). The deviation attributed to the Higgs boson data is compared with a Higgs simulation (dotted red line) at 120 GeV. The original article was published in Physical Review Letters, in March 2012. The paper itself is six pages long, but the list of authors, which follows the references, is fifteen pages long with many authors listed on a single line, acknowledging that it takes a village to find the Higgs boson: in this case, it’s a global village. Most Physics departments around the world have one or more physicists working on one aspect or another of the LHC project.

If the discovery of the Higgs boson is secured by additional experimental studies, it seems likely that when Obi Wan Kenobi of Star Wars fame claimed to have detected a disturbance in the Force, what he was really talking about was detecting the decay of the Higgs boson. We could not expect a former Jedi Knight to know about the Standard Model of atomic theory, so all can be forgiven for misrepresenting the true identity of the source.

RFM

 

  • Comments Off on A picture of the Higgs boson?

Higgs boson discovered

Posted on July 5th, 2012 in Science by Robert Miller

Scientists in Geneva celebrate as discovery of Higgs boson is announced (From the New York Times)

In an above the fold front page article in the NYT, scientists believe they have finally discovered the elusive Higgs boson particle, the one that gives mass to the atom. “I think we have it” said Rolf-Dieter Heuer, director general of CERN, the home of the Large Hadron Collider that was responsible for producing the new data by massively accelerating and colliding protons. While there remains some caution about the findings, it is a reason to celebrate and it is not too often that discoveries in particle physics make it into a front page, above the fold article in the New York Times. If this identification turns out to be correct, this is one of the most important discoveries in particle physics in decades and opens up all kinds of new possibilities for future research and modeling, including the possibility that the Higgs boson may help to unify the mechanisms of strong forces of atomic interactions and the weaker forces of gravity. But first more experimental work will be required to be certain that the identity of the new particle is secure. Perhaps it is another subatomic particle that would be equally important for further understanding the structure of the atom and its dynamic character.

RFM

  • Comments Off on Higgs boson discovered