“Nobody thought to look at the Four Corners until the SCIAMACHY data came out,” said Eric Kort, a scientist from the University of Michigan and lead author of a study describing the anomaly. By plugging the SCIAMACHY observations into computer simulations of the atmosphere, researchers estimated the area was emitting about 0.59 teragrams of methane per year-an amount equivalent to all of the methane emissions from the oil, gas, and coal industries in the United Kingdom for a year. SCIAMACHY observed a methane cloud about the size of Delaware it was the largest methane hot spot in North America to be detected by a satellite. While the area is known for having active gas, coal, and oil industries, nobody expected to find as much methane as the satellite did. “Unfortunately, these same areas in Africa, Asia, and South America are some of the places where ground-based sensor networks are lacking and cloud cover is the most problematic for satellites.”Īnother area that stood out in the SCIAMACHY data was the San Juan Basin in the Four Corners region of the western United States. “It is obvious from the global data that understanding what is happening in wetlands, especially tropical wetlands, is critical to understanding global trends,” said Frankenberg, who is now based at the Jet Propulsion Laboratory. This does not let us off the hook for reducing carbon dioxide, but the benefits of carbon dioxide reductions will come much later.” “Part of the reason there is so much interest in methane right now is because reducing those emissions could slow warming over the next few decades. “That means the climate effects of methane are front-loaded,” explained Drew Shindell, a climate scientist at Duke University. The difference occurs because methane is mostly scrubbed out of the air by chemical reactions within about ten years, while carbon dioxide persists in the atmosphere for much longer than a century. Over a century, that warming potential is 28 to 36 times greater. Over a 20-year period, one ton of methane has a global warming potential that is 84 to 87 times greater than carbon dioxide. (CO 2 is roughly 200 times more abundant.) Yet scientists attribute about one-sixth of recent global warming to methane emissions what methane lacks in volume it makes up for in potency. Methane makes up just 0.00018 percent of the atmosphere, compared to 0.039 percent for carbon dioxide. And carbon emissions are central to that rise.
The most recent decade was the warmest on the record. Global temperatures in 20 were warmer than at any other time in the modern temperature record, which dates back to 1880. Scientists wonder if they will have the right monitoring systems in place to answer that question adequately. “There is no question that methane is doing some very odd and worrying things,” said Euan Nisbet, an atmospheric scientist at Royal Holloway, University of London. Others wonder if changes in agriculture may be playing a role. Others point to the natural gas fracking boom in North America and its sometimes leaky infrastructure. Some scientists think tropical wetlands have gotten a bit wetter and are releasing more gas.
Since 2007, methane has been on the rise, and no one is quite sure why. Over the same period, emissions from natural sources have stayed about the same.īut if you focus on just the past five decades-when modern scientific tools have been available to detect atmospheric methane-there have been fluctuations in methane levels that are harder to explain. The reason is simple: increasing human populations since the Industrial Revolution have meant more agriculture, more waste, and more fossil fuel production. The concentration of the gas was relatively steady for hundreds of thousands of years, but then started to increase rapidly around 1750. The long-term, global trend for atmospheric methane is clear. And eye-popping videos on the Internet show scientists lighting methane-rich Alaskan lakes on fire. Radar observations have shown bubbles of methane rising from the depths of the Arctic Ocean. In October 2014, scientists announced they had discovered satellite signals of a methane hotspot over the Four Corners region of the United States.
Mysterious craters venting methane have appeared in Siberia’s Yamal Peninsula. Nighttime satellite images show points of light-some of them gas flares-in rural parts of North Dakota, Texas, and Colorado. In recent years, the gas has started to turn up in some surprising places.
0 kommentar(er)
