California gas leak largest methane leak in U.S. history

Monday, February 29, 2016, 4:43 PM - California's massive gas leak that spewed toxic methane into the atmosphere for nearly four months starting in October 2015 and forcing the evacuation of 1800 homes was the largest methane leak in U.S. history, a new study has found.

The Aliso Canyon leak emitted 97,100 tons of methane, equivalent to the annual greenhouse gas pollution from 572,000 cars, researchers say.

In a separate study published this month, researchers say the U.S. generates a substantial amount of methane gas, possibly responsible for 30 to 60 percent of the growth in emissions since 2002.

LEAK PLUGGED AFTER 16 WEEKS

On February 18, engineers were able to plug the 16-week leak, allowing thousands of Los Angeles residents to return home.

According to the Associated Press, the leak is expected to cost SoCalGas between $250 and 300 million. That figure does not include potential costs of 65 lawsuits filed by families who suffered nausea, nose bleeds and dizzy spells after inhaling the fumes.

California Governor Jerry Brown declared a state of emergency early January, as the leak had forced the evacuation of thousands of residents in Porter Ranch. It is expected that the seepage was caused by the changing dynamics deep underground where the gas is stored, according to Los Angeles Daily News.

Some experts have called the leak the worst environmental disaster in the U.S. since the BP oil spill.

Earlier in December, The Los Angeles city attorney filed a suit against SoCalGas, arguing locals should not have "to endure what the residents of Porter Ranch have suffered from the gas company's continued failure to stop the leak."

"It's not only the odour, it's the potential health consequences from the long-term exposure to chemicals like benzene," attorney Mike Feuer added, according to Phys.org.

Several area schools were closed and some 6,400 families were displaced due to the leak.

WHAT IS METHANE?

Methane is among the most prevalent greenhouse gases emitted in North America, arising from human activity. It is also emitted by natural sources.

While it doesn't remain in the atmosphere as long as the greenhouse gas carbon monoxide (CO2), it is much more efficient at trapping heat than CO2, making it a large contributor to climate change. 

WHAT IS CLIMATE CHANGE?

When scientists refer to 'climate change', they're talking about a change in climatic norms.

In other words, warm climates could get even warmer and drier, or they could get colder and wetter.

While this occurs naturally, scientists say humans play a role as well.

Here's an explanation from The Weather Network's Chris St. Clair:

Sources: Gizmodo | IBT | Environmental Protection Agency | Bloomberg | Phys.org | LA Times | National Post | Mashable