A state of emergency has been declared in California over a broken natural gas well that is leaking natural gas into the atmosphere and displacing thousands of families. How does the scale of the incident compare?

The methane and other pollutants spewing from the well is invisible to the naked eye, making it hard to comprehend just how large the leak is.

Fortunately, the California Air Resources Board (Carb) has been taking periodic measurements - the most recently available being from 22 December - which we can use to make some comparisons.

Bovine belching

Cows burping for a year 1.77m approximate number of cows burping for a year to produce equivalent methane 13,107 number of average US dairy farms needed to house the belching bovine Getty Images

During digestion, microbes in cows' stomachs produce methane which they then burp out - to the tune of about 150kg (330.7lbs) per year for your typical mid-sized cow, according to Science News.

All of this burping has prompted some to ask if eating meat can be eco-friendly.

Data from Carb suggests the gas leak outside of Los Angeles is spewing about 30,300kg of methane into the atmosphere per hour. At that rate, at least 265,428,000kg would be released in a year.

If producing methane were a job, the gas leak would be putting about 1.77m cows out of business in a year.

Cars & carbon

Methane is a powerful greenhouse gas. Over a 100-year period, it has about a 25-times greater impact on climate change than the equivalent amount of carbon dioxide, the gas produced by running cars and other vehicles, according to the US Environmental Protection Agency (EPA).

If the gas well were to continue at its current rate and produce 265,428,000kg this year, that would have the same greenhouse effect of 6,635,700,000kg of carbon dioxide.

According to the EPA, the average car on a US highway produces about 4,700kg of carbon dioxide per year.

So, to have the same greenhouse effect as the leaking California gas well, more than 1,411,851 cars would need to be added to the road.

Or in a single car, one would have to drive about 16,145,255,474.5mi (25,983,270,026.4km).

A few ways that distance could be covered:

5.8m trips between New York and Los Angeles

1.9m trips between Cairo and Cape Town

39.2m trips between London and Glasgow

3.58m trips between Caracas and Buenos Aires

Or, if you could drive on water and off-road, you would have to circle the earth 648,351.8 times

Displaced families

Displaced families 11,296 approximate number of people who have been temporarily relocated by SoCal Gas 176 London New Routemaster buses that could be filled

2,259 New York City taxi cabs that could be filled

12.2% amount of UCLA's Rose Bowl they could fill Getty Images

While the well is situated in a mountainous area more than a mile away from residential areas, residents have complained of health effects like headaches, nausea, vomiting and trouble breathing.

SoCal Gas says that "scientists agree natural gas is not toxic and that its odorant is harmless at the minute levels at which it is added to natural gas".

Regardless, the utility company has been paying to temporarily relocate and house residents from the affluent suburb outside of Los Angeles, known as Porter Ranch.

As of 7 January, the company said it had temporarily relocated 2,824 households. A spokesman for the company told the BBC that a household is typically about four people.

If those people, approximately 11,296 in total, were all together they would: