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I learned – Fracked gas and global warming

In 2015, the US put less carbon dioxide into the atmosphere than in any year since 1993, and it’s because of natural gas fracking. I wanted to understand: Is this a critical step towards slowing global warming? Or is have we made a deal with the devil?

**Note, I’m going to be sticking to global warming here, without reference to local air pollution or the water table. Only so much I can fit in one post!**

It seems like good news that we are emitting less CO2. US carbon emissions actually peaked in 2007, prior to the economic meltdown of 2008. But even as the economy recovered, carbon dioxide emissions kept declining every year, dropping by about 1.3% in 2015.

Carbon emissions are going down because dirty, carbon-intensive coal has been chased from the market by cheap natural gas created by fracking. As fracked gas has flooded the market, the demand for coal has crashed, with the price falling by half over the last five years. And because burning gas in a modern plant releases less than half of the carbon of burning coal, we have found it much easier to wean ourselves off of carbon.

But is this entirely a good thing?

Natural gas has a chemical name – methane – and methane is more powerful as a greenhouse gas than carbon dioxide – molecule for molecule, about 37 times more powerful. Its power stems, paradoxically, from the fact that it lasts only a few years in the atmosphere before it decomposes to form CO2. Because there is never a lot of it in the atmosphere at any given time, all the bits we add have a much bigger impact.

This matters a lot because not all of the gas we extract ends up being burnt into energy. Inevitably, some methane leaks into the atmosphere, passing through pores in the concrete seals that are supposed to contain the gas to the well, or through imperfections in welds that hold the pipelines together. And if enough leaks, the methane could warm the planet to a greater degree than the carbon dioxide it burns into.

This is a situation where the exact numbers have huge policy implications. The folks at the Environmental Defense Fund did the world a service by publishing some numbers back in 2012, when they calculated an acceptable leak rate for natural gas, below which the switch from coal to gas slows down global warming.

The magic number is 3.2% – if less than 3.2% of gas gets into the environment, then switching from coal to gas will aid in our fight against warming. And in even better news, the gas industry more or less agrees — gas lobbying groups actually provide hyperlinks to the EDF website on this.

Now that we know the theory, all we have to do is get everyone to agree on what the actual leak rate is in real life.

For example, if the number is 2% – a 2009 estimate by the Environmental Protection Agency – then a switch to natural gas will provide both environmental and economic benefits. But if the number is 12% – as estimated by a researcher at Cornell – than natural gas is an unmitigated disaster that will hasten the boiling of the planet.

Who do you believe?

This problem comes up a lot in early work in any scientific field – initial estimates are all over the place. It happens because researchers use different measurement techniques, or sample from different locations. Or just plain make mistakes, which take a while to find and correct.

It was only recently that scientists started to care enough about the issue to invest in repeated measurements, and we are still learning exactly how to do them right. But more and more measurements are coming out near, or just below, that 3.2% figure. And while that might not be great news – I’d like us to be benefiting more from the death of coal – it gives cause for hope, for two reasons.

The first reason for hope is that if there is one thing engineers are good at, it’s making slow, steady improvements to things. If we are starting near 3% today, there is every reason to believe we’ll continue to lower this with incremental innovations if the right incentives exist.

The second reason for hope is that, at a 3% leak rate, the natural gas industry is letting $1.5 billion a year literally vanish into thin air. Incentives exist.

Now, I’ll be clear that I don’t think the industry will do everything it needs to on its own. Capitalism is made of people, and a significant fraction of people try to avoid change, even if it’s in their best interest. So having the threat of pain (in the form of government regulation) is almost certainly needed to move them in the right direction. And, just as important, the faster we drop this leak rate, the more benefit we get from the switch to gas.

But we appear to be doing fine for now, with a believable path to even better performance – one that didn’t exist in a coal-powered economy. And because methane lasts only a decade in the atmosphere, in the long run the effects of switching to gas are greater still. And let’s be clear that this is a long game: even under a Manhattan Project style investment in renewables, it would still take over a decade before solar and wind could effectively replace gas across the nation. The improvements we make now matter.

So while we build that cleaner future, fracked gas will dominate electricity production. And we are globally a little bit better off because it does.

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