As a means to counter outside economic pressure, natural gas's usefulness is clear.
One is a sensor that can pinpoint the gas's concentration at a particular point.
But natural gas's share, now a little over one-fifth, is rising as more supplies are found and prices drop.
The gas's action, the manual states, continues for 48-72 hourso so repeating every few days is a good idea.
The effect that boosting this gas's concentration in the atmosphere will have on plants is very poorly understood.
Institutions, governments and individuals who want to reduce greenhouse gas emissions worry about gas's rise, because it will replace cleaner nuclear power.
An extrapolation of these trends published by the International Energy Agency on June 6th showed gas's share of energy provision overtaking coal's in less than 20 years.
The Scripps Institution launched a Twitter account, @keeling_curve, to make it easy for people to track the gas's path through 400 and beyond.
This offsets natural gas's most important advantage as an energy source: it burns cleaner than other fossil fuels and releases lower carbon dioxide emissions.
In a few years shale gas's share of America's total gas output has gone from almost nothing to around a fifth.
Methane has 20 times the global warming potential of carbon dioxide, and if too much is leaked, gas's advantage over coal is reduced.
