00:10What could possibly go wrong, ignoring climate change, the warnings or clues from what science tells us?
00:18Even if we were just creating a better world with clean energy and millions of new jobs.
00:25One thing which could go very wrong are based on the so-called positive feedbacks, that is triggering additional processes
00:33which eventually lead to more warming.
00:38One of those suspected feedbacks is the release of methane stored or trapped in large quantities in frozen soils in
00:47the Arctic or Antarctica,
00:50produced in soils if conditions are right.
00:54Metaine, also most commonly observed in gaseous form, can sometimes become trapped at the bottom of the ocean in very
01:04deep or cold regions,
01:06freezing into a solid substance known as methane hydrate, also called methane cladrate.
01:14Ice-like crystal structures of water forming a solid similar to that of ice and is flammable.
01:29Originally thought to occur only in the outer regions of the solar system, where temperatures are low and water ice
01:38is common,
01:39significant deposits of methane cladrate have been found under sediments on the ocean floors of the Earth.
01:47The observed density of cladrates is around 0.9 g per cubic centimeter,
01:54which means that methane hydrate will float to the surface of the sea unless it is bound in place by
02:02being formed in or anchored to sediments.
02:06One cubic meter of the compound releases about 160 cubic meters of methane gas.
02:14This matters because methane is a potent greenhouse gas, its global warming potential,
02:20the effect on the atmosphere is up to 34 times as strong as that of carbon dioxide over a period
02:28of 100 years or so, according to the IPCC.
02:33But in the first decade or two, before decaying to CO2, methane's warming potential is 86 times as much as
02:43that of CO2.
02:44New discoveries described in the study.
02:47Massive blowout craters formed by hydrate-controlled methane expulsion from the Arctic seafloor.
02:54Published June 2017 in the journal Science by a team of researchers from CAGE Center for Arctic Gas, Hydrate, Environment
03:04and Climate from Norway,
03:06are the latest of recent findings in climate science suggesting Arctic methane explosions took place in the ancient past.
03:16And could this happen again? And how would affect it the climate today?
03:22The study is based on research of hundreds of massive kilometer-wide craters on the ocean floor in the Barents
03:30Sea,
03:31a region of the Arctic Ocean stretching between Norway and Russia.
03:35There, at the bottom of the ocean floor, stands a collection of more than 100 craters,
03:41some as much as 1 kilometer wide and nearly 300 meters deep.
03:47The researchers believe they were formed by sudden rushes of methane from the seafloor nearly 12,000 years ago,
03:57when a sudden burst of methane surged from the bottom of the Arctic Ocean, leaving an array of gigantic craters
04:06in its wake.
04:07A few of these craters were first observed in the 90s,
04:11and new findings show that the craters cover a much larger area than previously thought.
04:16In comparison, the huge blowout craters on land, recently observed on the Siberian peninsulas Jamal and Goeden,
04:25are 50 to 90 meters wide, but similar processes may have been involved in their formation.
04:32The crater area on the bottom of the Arctic Ocean was covered by a thick ice sheet
04:37during the last ice age, much as West Antarctica is today.
04:42As the climate warmed and the ice sheets were thinning and retreating,
04:46increased concentrations of gas hydrates accumulated in shallow layers below the ice sheet.
04:53As this happened, the space in the ground, where conditions were right for the hydrates to remain stable, grew thinner
05:01and thinner.
05:02And as the ice continued to retreat and the enormous pressure was relieved,
05:08Earth's crust began to bounce back into shape.
05:13These factors further contributed to the compression of the hydrates in the Arctic sediment
05:20and began to cause mounds to rise up at the bottom of the newly formed sea.
05:26Finally, at one point, enormous amounts of methane were abruptly released, creating the massive underwater craters.
05:34I think it was probably like a lot of champagne bottles being opened at different times, explained Karen Andresian,
05:43the new paper's lead author and professor of marine geology and geophysics.
05:48Also, there is no evidence that other sudden bursts have occurred in the region since there appears to still be
05:56a substantial reservoir of gas there.
05:59To this day, methane and other hydrocarbons continue to slowly vent from the seafloor and probably have been since the
06:08explosions occurred.
06:10There is evidence of other intact hydrates still in the region, mounds that have yet to burst, and what will
06:16happen to them in the future remains unclear.
06:20Scientists generally believe that the methane leaking from these seeps never makes it to the surface of the ocean,
06:29instead dissolving in the water on its way up.
06:33But some suggest that an explosion of the type described could produce enough force to send some gas straight up
06:41to the surface and into the atmosphere.
06:43As for the Metanina explosion, it's not the only such event to have occurred in ancient Arctic history.
06:50Graspi, the Natural Resources Canada scientist, recently published research describing a cluster of rocky mounds in the Canadian Arctic
07:01that researchers believe were also caused by an ancient Metanina explosion, also much further in the past.
07:09Graspi's mounds were likely formed about 100 million years ago, probably after a sudden warming period in Earth's history, destabilized
07:19the hydrates.
07:20His paper raised the question of whether modern-day Arctic warming could be priming the region for another methane explosion
07:29in the future
07:29and whether that gas could make it to the atmosphere.
07:33The concern is that this scenario could lead to a dramatic amplification of global warming, even potentially triggering a climate
07:45feedback loop in which more warming causes more Metanina to be released.
07:53Andresen cautioned that these theories have no concrete support for the time being, noting that it would be a dramatic
08:02conclusion to assume that ancient Metanina explosions had a significant effect on the climate without substantial extra work to back
08:12up the idea.
08:13Still, because Metaninhydrates do still exist in the region and conditions in the Arctic are rapidly changing thanks to global
08:23warming, it's a scenario deserving continued attention.
08:42The end of the Unto
08:48To be continued...
08:49The end of the story and the end of the story is inWill
