As scary as worldwide signs of melting glaciers certainly are, they pale in comparison with the possibility that we will reach the point where large volumes of clathrates (methane hydrates) frozen in the arctic tundra and in undersea deposits suddenly begin to melt in massive quantities and produce so-called "methane burps." Al Gore warned of this in his 1993 book
Earth in the Balance, and no one listened. However, when we have scientists telling us that the arctic polar ice has thinned 40% over the last two decades, that there may be no glaciers left anywhere on Earth by the end of this century and that the fabled "Northwest Passage" from the Atlantic Ocean to the Pacific (of which explorers like Henry Hudson once dreamed and for which they repeatedly searched in vain) may become a permanent reality within as little as a few more decades, it is time we all started listening.
A possible consequence of such a cataclysmic event is no less than a massive die-off of species, which is quite likely to include us. Even if things do not go quite that far, massive loss of human life would almost certainly occur.
Methane (CH4) is a greenhouse gas that has many times as powerful an effect in warming the earth's atmosphere as does carbon dioxide (CO2). Normally, methane is kept in check by negative feedback loops or methane "sinks" that exert a dampening effect. Probably the most potent of these are when methane becomes dissolved in ocean water and is oxydized to CO2 through several intermediate steps or freezes in combination with water in cold regions to produce methane hydrates.
The earth seems to be able to accomodate normal quantities of methane entering and leaving the atmosphere, but many scientists have expressed concern over the possibility that a positive feedback loop may take over if larger amounts of methane begin entering the atmosphere that can be cycled out by methane sinks. The analogy is sometimes used to a car heater's thermostat. Under normal conditions, when the car becomes too cold, the lower set point of the thermostat will turn on the heater and warm the interior until the temperature reaches the upper set point, at which time the thermostat turns the heat off. However, If you switch the terminals of the thermostat, the heater stays off until the interior air is heated to the upper set point, which causes the heater to come on and stay on. Then the heater runs out of of control and heats the car to an unbearable, and likely lethal, extent.
In a similar manner, global warming due to increased concentrations of CO2, methane and other greenhouse gases in the atmosphere has the potential to cause temperatures in arctic regions to reach the point where large volumes of methane begin to melt. Then, the methane, which has 30 times the heat-trapping ability of CO2 and is estimated to be 20 to 21 times as potent a greenhouse gas overall as CO2, will likely cause the arctic temperatures to rise faster and melt more CH4, which will cause the temperature to rise even faster. The temperature ultimately runs out of control.This is, in fact, what scientists think occurred on Venus and Mars and is why their atmospheres are so inhospitable to life. It is also believed to have happened more than once on the Earth, most famously at the end of the Permian age, when a mass extinction believed to have been caused by an enormous increase in atmospheric CH4 and CO2 concentrations wiped out as much as 80 percent of all species on the planet (including up to 95 percent of all marine species) and almost snuffed out animal life completely. <
http://archives.cnn.com/2000/NATURE/07/27/ocean.methane... >; <
http://palaeo.gly.bris.ac.uk/Essays/wipeout/default.htm... >; <
http://news.bbc.co.uk/2/hi/science/nature/3451787.stm >.
Scientists differ on just how likely this is to occur. However, even if the probability is relatively low, as some believe, the effects if it does happen are so drastic and irreversible (at least on any human time scale), that we really cannot afford to risk such an occurance. We are almost certainly not going to get a "do over" or even be able to stop it if such a "runaway greenhouse effect" does, in fact, occur.
This is perhaps the strongest reason of all why we need to convert to a renewable fuels economy right away. For example, we can use solar, wind and geothermal energy to generate the electricity needed to use "reverse fuel cells" to convert water into hydrogen gas (H2), with oxygen (O2) as a byproduct. We then use fuel cells in our vehicles to combine the hydrogen with atmospheric oxygen to produce energy to drive the automobiles, with water as the only byproduct. By doing this, we will begin to slow down the rate at which a major source of CO2 enters the atmosphere, which will, in turn, slow the rate at which CH4 is produced from methane hydrates.
Similarly, by using solar towers, PV panels, passive solar collectors, wind turbines and geothermal generating plants to produce much higher portions of our other electical generating needs, we will begin to stop our current dependence on coal as our largest source of electrical energy and put an even greater dent in the rate at which greenhouse gases are increasing in the atmosphere. If we work long enough and hard enough at it, we may even stop or reverse the trend toward higher and higher levels of atmospheric greenhouse gases.
The problem is that we do not have time to allow the electrical utilities in the U.S. to continue burn up all of the available coal before making the switch. There is a very strong possibility that, in so doing, they will cause global concentrations of greenhouse gases to go beynd the tipping point and cause an irreversible catastrophe.
According to John Atcheson, a geologist who has held a variety of government policy positions and who wrote on this subject in the December 15, 2004 edition of the
Baltimore Sun:
"The Arctic Council's recent report on the effects of global warming in the far north paints a grim picture: global floods, extinction of polar bears and other marine mammals, collapsed fisheries. But it ignored a ticking time bomb buried in the Arctic tundra.
"There are enormous quantities of naturally occurring greenhouse gasses trapped in ice-like structures in the cold northern muds and at the bottom of the seas. These ices, called clathrates, contain 3,000 times as much methane as is in the atmosphere. Methane is more than 20 times as strong a greenhouse gas as carbon dioxide.
"Now here's the scary part. A temperature increase of merely a few degrees would cause these gases to volatilize and "burp" into the atmosphere, which would further raise temperatures, which would release yet more methane, heating the Earth and seas further, and so on. There's 400 gigatons of methane locked in the frozen arctic tundra - enough to start this chain reaction - and the kind of warming the Arctic Council predicts is sufficient to melt the clathrates and release these greenhouse gases into the atmosphere.
"Once triggered, this cycle could result in runaway global warming the likes of which even the most pessimistic doomsayers aren't talking about.
"An apocalyptic fantasy concocted by hysterical environmentalists? Unfortunately, no. Strong geologic evidence suggests something similar has happened at least twice before.
"The most recent of these catastrophes occurred about 55 million years ago in what geologists call the Paleocene-Eocene Thermal Maximum (PETM), when methane burps caused rapid warming and massive die-offs, disrupting the climate for more than 100,000 years.
"The granddaddy of these catastrophes occurred 251 million years ago, at the end of the Permian period, when a series of methane burps came close to wiping out all life on Earth.
....
"If we trigger this runaway release of methane, there's no turning back. No do-overs. Once it starts, it's likely to play out all the way.
"Humans appear to be capable of emitting carbon dioxide in quantities comparable to the volcanic activity that started these chain reactions. According to the U.S. Geological Survey, burning fossil fuels releases more than 150 times the amount of carbon dioxide emitted by volcanoes - the equivalent of nearly 17,000 additional volcanoes the size of Hawaii's Kilauea.
"And that is the time bomb the Arctic Council ignored.
"How likely is it that humans will cause methane burps by burning fossil fuels? No one knows. But it is somewhere between possible and likely at this point, and it becomes more likely with each passing year that we fail to act.
"So forget rising sea levels, melting ice caps, more intense storms, more floods, destruction of habitats and the extinction of polar bears. Forget warnings that global warming might turn some of the world's major agricultural areas into deserts and increase the range of tropical diseases, even though this is the stuff we're pretty sure will happen.
"Instead, let's just get with the Bush administration's policy of pre-emption. We can't afford to have the first sign of a failed energy policy be the mass extinction of life on Earth. We have to act now."
<
http://www.newmediaexplorer.org/sepp/2005/02/01/global_... >.