Earth’s collision course with destiny?
The experts have spoken. Their prognoses are in — and they are dire. If steps are not taken soon to reverse the trend, we — and our planet — are headed for disaster…
Earth’s collision course with destiny?
Sat, 31 Jul 2010
By Tahereh Ghanaati
Imagine the world a baking desert with an atmosphere so poisonous that to breathe the air would mean instant death.
Imagine the sky a blanket of thick and noxious clouds of sulfur dioxide blocking out the sun and rendering daylight a dim and smoky haze.
Imagine a world of searing heat with temperatures reaching 460 degrees Celsius (860 degrees Fahrenheit.) And when the hurricane force wind scourges the cracked and blistered surface of the land, it is like the breath of a blast furnace.
Is this nightmarish world a product of science fiction? It is a description of Dante’s Inferno? Actually, it is neither. It is Venus, which is called our world’s ‘sister planet’ and which scientists now believe to have once been very much like Earth, itself.
What happened? What transformed Venus, which experts believe once had water and may have been capable of supporting life, into the ‘planet from Hell?’
The answer is the ‘runaway greenhouse effect’ – the end result of unchecked global warming. Moreover, numbers of scientists now think that Earth may well be on a collision course with the same grim fate if global warming continues at its present rate.
According to the findings of a year-long study of Venus (the Venus Express Probe) by the European Space Agency, the planet was once very much like Earth, but ‘runaway greenhouse’ changed it into something quite different.
Professor Fred Taylor, of Oxford University’s Department of Physics, who took part in the study and was one of its leaders, said, “It is now becoming clear why the climate on Venus is so different from the Earth, when the planets themselves are otherwise quite similar. Our new data make it possible to construct a scenario in which Venus started out like the Earth – possibly including a habitable environment, billions of years ago – and then evolved to the state we see now.”
Scientists now believe that Venus once possessed oceans. However, as frequent volcanic eruptions caused a buildup of carbon dioxide in the atmosphere, temperatures rose and the seas evaporated.
Unchecked global warming then spawned ‘runaway greenhouse,’ a phenomenon that occurs when a planet absorbs more energy from the sun than it can radiate back into space. When this happens, rising temperatures cause a greenhouse effect, which in turn, causes the temperatures to rise even higher and the result is a vicious cycle.
But could such an event actually take place on Earth? And if so, what are the warning signs? How can we tell if global warming on our planet is on the increase?
As regards the first question, the scientific community is divided. However, most of its members concede that global temperatures are on the rise and might possibly set off a chain reaction.
A 2007 study by the Netherlands’ Utrecht University found that the Earth’s greenhouse warming, which took place during the Paleocene-Eocene thermal maximum (PETM) phase 55 million years ago, was caused by a relatively rapid buildup of carbon dioxide in the atmosphere. Intense volcanic activity was most probably the reason for the buildup.
The CO2 concentrations triggered a greenhouse effect, which in turn, warmed the oceans. As oceanic temperatures increased, submarine methane hydrates melted and large amounts of methane were released into the atmosphere, which further aggravated the problem.
In other words, the study showed that a rapid buildup of CO2 in the atmosphere once caused a chain reaction resulting in a greenhouse effect — and could conceivably do so again.
But how do we know when carbon dioxide in the atmosphere has reached dangerous levels? What signs should we look for?
Our best barometers are the oceans, which cover 71 percent of the Earth’s surface and absorb a great portion of its excess heat. When their temperatures begin to climb, we can be fairly certain that global warming is well underway.
And according to a report, which appeared in Science magazine on June 18, 2010, oceanic temperatures are on the rise. In fact, the report, which was jointly compiled by Ove Hoegh-Guldberg, who is director of the Global Change Institute at the University of Queensland in Australia and John Bruno, an associate professor of marine sciences at the University of North Carolina at Chapel Hill in the United States, warns that the oceans are not only warming, but their acidity levels are increasing, as well.
Hoegh-Guldberg called the findings “further evidence (that) we are well on our way to the next great extinction event.”
Bruno added that certainty is increasing that “the world’s marine ecosystems are reaching tipping points.”
The report goes on to say that warmer temperatures (which cause polar icecaps to melt, decreasing the salinity of surface water,) could also cause a disruption of major ocean currents, particularly the north-south conveyors, which circulate warm equatorial waters to polar regions and vice versa.
The report warns that “the steady increase in heat content in the ocean and atmosphere are likely to have profound influences on the strength, direction and behavior of the world’s major current systems.”
Nate Mantua, an associate research professor at the University of Washington’s Climate Impacts Group said, after reading the report that it is “a lot worse than the public thinks.”
He added that there is also growing concern about oceanic ‘dead zones’ (low-oxygen or no-oxygen zones,) which are appearing more and more regularly off the northwestern coast of North America.
In fact, dead zones are on the increase across the globe. Earth’s seas and oceans currently have over 400 dead zones, which contain a total of 152,000 square miles. And according to the US National Science Foundation, the numbers double each decade.
Of course, these figures are based on findings prior to the recent Gulf of Mexico oil disaster. The massive oil spill began on April 20, of this year when the Deepwater Horizon offshore rig exploded and shattered the Macondo wellhead, causing an underwater gusher. Since that time (according to US government estimates,) around 60,000 barrels of crude a day have spilled into the Gulf.
Thus it is not surprising that a research expedition in mid-June found as much as a million times the normal level of methane gas in parts of the Gulf near the spill.
Texas A & M University oceanography professor John Kessler, who was a member of the team, called the event the “most vigorous methane eruption in modern human history.”
“There is an incredible amount of methane in there,” Reuters reported Kessler as saying. “We saw them approach a million times above background concentrations” in some areas, he added.
The group’s findings correlate with figures released by the US Geological Survey “flow team” which has estimated that 2,900 cubic feet of natural gas – mainly methane – are being released into the Gulf with every barrel of oil.
It might be mentioned that the presence of large amounts of methane does not only deplete oxygen levels and cause dead zones. The gas also acts as a major heat trap. It is 23 times more capable than CO2 of trapping solar radiation. Thus it acts as a powerful accelerant for global warming.
It is generally conceded that the oil spill will widen and worsen the Gulf of Mexico dead zone. But what do aquatic dead zones have to do with global warming?
In the March 12, 2010 issue of the US Science journal, Dr. Lou Codispoti, an oceanographer for the University of Maryland Center for Environmental Science, explained that the increased amounts of nitrous oxide (N2O) found in dead zones (hypoxic waters,) raise concentrations in the atmosphere, thus worsening global warming.
“As the volume of hypoxic waters move towards the sea surface and expand along our coasts, their ability to produce the greenhouse gas nitrous oxide increases,” Dr. Codispoti stated. “With low-oxygen waters currently producing about half of the ocean’s net nitrous oxide, we could see an additional significant atmospheric increase if these ‘dead zones’ continue to expand,” he added.
Like methane and CO2, nitrous oxide is a potent greenhouse gas. As dead zones increase, N2O production will rise and more of the gas will be released into the atmosphere.
We might expect such conditions in the Gulf of Mexico. After all, the oil spill is a disaster of almost unprecedented proportions; but what about the Pacific Ocean?
When most of us think of that vast aquatic stretch, especially the South Pacific, we think of crystalline waters and brilliantly-hued underwater vistas of coral reefs teeming with life.
But according to Dr. J. E. N. “Charlie” Veron, the former chief scientist at the Australian Institute of Marine Science, the reality will soon be entirely different.
In the July 7, 2009 issue of London’s Sunday Times, Dr. Veron said that within 20 years, the Great Barrier Reef will be gone.
There is no way out, no loopholes,” the newspaper quoted him as saying. “The Great Barrier Reef will be over within 20 years or so. Once carbon dioxide hits the levels predicted for between 2030 and 2060, all the world’s coral reefs will be doomed to extinction.”
Coral reefs help control the amount of CO2 in the oceans. If these regulators were to die out, the amount of carbon dioxide throughout the world would rise dramatically, thus rapidly increasing greenhouse gases.
The experts have spoken. Their prognoses are in — and they are dire. If steps are not taken soon to reverse the trend, we — and our planet — are headed for disaster.