Can CRISPR Stop Cows from Fueling Climate Change? Gene Editing Takes Aim at Methane

Scientists are using CRISPR to cut methane emissions in cows—innovation or risky DNA experiment?

Cows have a climate problem, although in fairness to the cows, they are not entirely responsible for it.

A lot of the methane associated with cattle comes from microbes living inside their digestive systems. Those microbes help cows turn grass and other plant material into energy, which is quite useful if you are a cow. The unfortunate byproduct is methane, released mostly through belching.

Multiply that by roughly a billion and a half cattle around the world and suddenly the burps become everybody’s problem.

Scientists have been trying to reduce those emissions for years using feed additives, breeding, and other approaches. Then I came across a Washington Post article about a team exploring a considerably stranger possibility: change the microbes themselves.

Using CRISPR.

Inside cows.

Obviously I kept reading.

The researchers aren’t trying to genetically redesign the animal. The target is its microbiome, the huge community of organisms already living inside it. The long-term idea is that if scientists can establish a lower-methane microbial community early in a calf’s life, perhaps through some kind of oral treatment, the effect might last much longer than a feed additive that has to be continually supplied.

That could be particularly useful for cattle grazing across large areas, where slipping something special into breakfast every morning is not exactly practical.

When I first read about the project, much of the work involved figuring out which microbes were doing what and which ones might be useful targets. Since then, researchers have made more progress understanding the relationships inside that ecosystem and what might allow methane production to drop without simply creating another biological problem somewhere else. And therein lies the fun.

A microbiome is not a row of tiny switches. It is an ecosystem full of organisms that have been interacting with each other and their host for a very long time. Changing one part may affect another in ways that aren't immediately obvious.

This doesn't make me think, Stop immediately. It makes me think, Okay, what happens next? That distinction probably explains why I find technologies like CRISPR so interesting in the first place.

One of the scientists involved in the broader effort is Brad Ringeisen, executive director of the Innovative Genomics Institute and a former DARPA biotechnology program manager. In the original reporting, he talked about bringing a “DARPA mentality” to the challenge: don't solve the problem for a handful of animals under perfect conditions. Think about whether you can build something that might eventually work at enormous scale.

I love that mentality. It also makes the author in me slightly nervous, which is generally a good sign.

There’s an appealing logic here. If you can alter the microbial process responsible for a significant amount of methane and make the change durable, you may have a climate tool that doesn't depend on every farmer everywhere adopting the same feeding regimen forever.

At the same time, biology has spent several billion years developing an impressive resistance to our desire for simple solutions.

That’s the piece of this story I keep coming back to. Not whether CRISPR is good or bad, or whether scientists should leave nature alone. We have been changing biological systems for as long as we've practiced agriculture.

The scale and precision are changing. And so are the things we can plausibly attempt.

Most conversations about CRISPR eventually end up with humans: inherited diseases, gene therapies, embryo editing, designer babies. Understandably. The ethical stakes are enormous and personal.

But cow-gut microbes are a useful reminder that gene editing could shape the future in much less obvious ways. We may end up altering microbial communities in animals, crops, soil, or other environments because those microscopic systems influence much larger problems.

Which means the question isn't always going to be, Should we rewrite DNA? Sometimes it will be: How much of this system do we actually understand before we start rearranging it?

I’m excited by the possibility that something as strange as engineering a cow’s microbiome could become a useful climate tool. I’m also perfectly comfortable admitting that “this might work” and “we understand everything that happens after it works” are very different statements.

Somewhere between those two statements is usually where I start paying attention.

In this particular case, somewhere between them is also a cow, quietly chewing grass while an international team of scientists debates the future of the microbes in its stomach.

The cow remains unavailable for comment.

Sources: This post was originally inspired by The Washington Post’s reporting on efforts to use CRISPR and microbiome science to reduce methane emissions from cattle and has been updated to reflect subsequent progress in the research.