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How Methane Gas Releases Due To Global Warming Could Cause Human Extinction
Although carbon dioxide (CO2) may play a key role in any potential future adverse effects associated with global warming, the question that mankind really needs to ask is: How Methane Gas Releases Due To Global Warming Could Cause Human Extinction?
As global warming and climate change research advance, it is becoming increasingly clear to many scientists and observers that the rising carbon dioxide level in the Earth’s atmosphere will not likely cause human extinction on its own, but will rather be the trigger to a tipping point event that will cause global warming to accelerate rapidly with dire consequences for mankind and all living creatures and organisms on planet Earth.
Methane Concentration In Earth's Atmosphere
Why Methane Gas Releases Due To Global Warming Are A Concern
Huge deposits of methane (CH4) are locked up in the permafrost above the Arctic Circle and in frozen methane ice, known as methane hydrate, underneath the ocean floors throughout the world and beneath the continental shelves in the polar regions. Scientists estimate that there are at least 200,000 trillion cubic feet of frozen methane in the form methane hydrate beneath the ocean floors. As the Earth's atmosphere and oceans warm, these frozen deposits of methane are being released at an increasing rate from the frozen state that they have been in for millions of years. This acceleration of methane gas releases from the permafrost and frozen methane hydrate deposits beneath the oceans is likely being caused by the build-up of carbon dioxide and methane greenhouse gases in the Earth’s atmosphere and their warming effect on the Earth’s atmosphere and oceans.
What troubles many climate scientists and other observers that are concerned about global warming is that methane is far more effective than carbon dioxide as a greenhouse gas. They worry that a surge in methane gas releases due to rising atmospheric and ocean temperatures could cause a rapid increase in average global temperatures.
As of this writing, methane concentrations in the Earth’s atmosphere have reached 1.8 parts per billion (ppb), which the geologic record indicates is the highest level in 500,000 years. For comparison, methane concentrations in the Earth’s atmosphere ranged between 0.6 and 0.8 ppb from the year 1000 to about the year 1850.
Methane is estimated to cause up to one hundred times more warming than carbon dioxide during its first twenty years in the Earth’s atmosphere. Over time, methane naturally breaks down in the atmosphere into carbon dioxide and water, but is still estimated to cause up to thirty times more warming than carbon dioxide from twenty to one-hundred years after its release into the Earth’s atmosphere.
Climate scientists and other observers predict that as the Earth’s atmosphere and oceans warm in response to the gradual buildup of carbon dioxide, methane will continue to be liberated from its frozen state in permafrost and beneath the sea floor at an increasingly rapid rate. This increasing rate of methane release into the Earth’s atmosphere will cause the global average temperature to increase even further, which will then feed upon itself in a positive feedback loop until a tipping point average global temperature threshold is reached and massive amounts of frozen methane are quickly released from their frozen state, causing a huge spike in global temperatures of up to 16 degrees Fahrenheit (10 degrees Celsius) over a matter of fifty to two hundred years. In other words, the current carbon dioxide and methane related global warming could be the trigger for the release of massive quantities of methane gases into the Earth’s atmosphere, which scientists call the “Methane Gun Hypothesis”. Many life forms on Earth would likely have a difficult time adapting to such a rapid and significant increase in average global temperatures and the direct effects of massive methane gas releases, and another mass extinction event, including possibly human extinction could ensue.
The Effects Of Massive Methane Gas Releases
Quickly rising global temperatures, as a result of massive methane gas releases from beneath the world’s oceans and permafrost, would cause major havoc for mankind, as the global climate changes rapidly. The likely result of a quick warming (perhaps as much as 16 Fahrenheit, based on similar quick warming events associated with massive methane gas releases that have been noted in the Earth’s geological record) would be difficult for mankind to contend with. Rises in sea levels on the order of hundreds of feet within a century would inundate highly populated coastal cities, coastal plains, and tidal inland waterways and lowlands. Many of the areas that mankind rely upon to grow food would be dried out by the significantly higher temperatures and changes in rainfall patterns that cause devastating droughts. In areas in which it does rain, the rain would be torrential at times, causing massive flooding and destruction. Storms, such as hurricanes (typhoons), would be incredibly powerful, as the significantly warmer atmosphere would be loaded with moisture and latent heat energy from warmer oceans that storms would tap to grow stronger.
After being released from the ocean floor, methane reacts with dissolved oxygen, as it moves up towards the surface of the ocean and forms carbon dioxide. This process reduces oxygen levels in the ocean, as the oxygen in the ocean combines with methane to form carbon dioxide, which can severely limit the amount of oxygen available for sea creatures, such as fish, causing them to die in large quantities. This would cut off a major source of sea-based food that humans rely upon for survival.
Scorched farmlands from the resulting unrelenting heat waves and droughts would cut off another major source of food that humans need to survive. Mass starvation would be likely, unless mankind adapted quickly to rapid climate change and figured out how to grow and produce food in alternative ways.
There will also be direct impacts that result from massive methane gas releases into the Earth’s atmosphere. Methane is a very flammable gas that is also explosive. As massive methane gas releases occur from long frozen methane hydrate deposits beneath the oceans, lighting from thunderstorms will cause the methane releases to catch fire, causing huge fireballs that will scorch areas of the Earth that are close to the oceans. These methane fireballs will result in large out of control wildfires on land that will cause further devastation.
Both the direct impacts of massive methane gas releases and indirect environmental impacts of such releases could threaten human survival as a species, unless humans rapidly adapt to the firestorms and the environmental impacts of a much warmer world.
Rapid Global Warming Due To Methane Gas Releases Has Happened Before
According to geologists and other scientists who study the clues regarding the Earth’s climate from past eras, massive methane gas releases that caused rapid global warming to occur have occurred several times in the Earth’s geological history. The most recent massive methane gas release and rapid global warming event was approximately 55 million years ago, when an estimate 20% of the Earth's frozen methane reserves rapidly melted. Geologic deposits indicate that the Earth’s atmosphere warmed dramatically during this event, with average global temperatures rising by 13 degrees Fahrenheit (8 degrees Celsius). This event is known as the Paleocene-Eocene Thermal Maximum (PETM). The geologic record of the Paleocene-Eocene Thermal Maximum event indicates that the Earth’s ice caps melted and many land and sea creatures became extinct, including up to 80% of the deep-sea creatures that lived in the oceans at the time.
Would Rapid Global Warming Due To Methane Gas Releases Lead To Human Extinction?
It is obviously a big step go from rapid global warming to the extinction of all human beings on Earth. Humans have proven to be incredibly adaptable creatures, especially since humans possess the intellectual skills to build shelters and machinery that can help them adapt to changing climates and temperature extremes. However, the climate variations that humans have experienced over the past couple of thousands of years, from the Medieval Warm Period (950 to 1250) to the Little Ice Age (1550 to 1850) pale in comparison to the dramatic global warming that humans would endure if massive methane gas releases cause rapid global warming.
Perhaps humans would somehow survive at high inland latitudes and elevations, where crop production may be possible in a dramatically warmer world during and after-massive methane releases from the oceans. However, since mankind has lived during a relatively stable interglacial climate period that has lasted for thousands of years and has not experienced global warming on the magnitude of 10 degrees Fahrenheit or more over a period of a century or two, it is difficult to predict with any confidence that the species homo sapiens could survive the abrupt warming that will occur during and after massive methane releases from the Earth's oceans. If the primary effects of massive methane releases, such as exploding methane fireballs at sea and firestorms on land do not cause mankind to go extinct, then the secondary environmental effects from severe droughts to severe storms that disrupt the food supply, or possible tertiary effects, such as disease migration and weakened immune systems, could cause mankind to eventually cease to exist as a life-form on planet Earth.
Methane Gas Explosion
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© 2012 John Coviello