That's one cow for every five people on Earth.

We keep them for dairy... and meat...

and they're a climate problem that we've struggled to solve.

Every year, each one of those cows is estimated

to release up to 220 pounds of methane...

mostly when they burp.

That's about 4% of all greenhouse gas emissions that are warming our planet...

from burping cows.

You've probably heard a few solutions to this

like trying to convince people to lower their beef intake...

or switch to meat alternatives.

But instead of trying to convince billions of humans to change their diets

some researchers are focusing on the diet of the cows.

And a promising solution might come in the form...

of seaweed.

This video is presented by Delta Airlines.

One of the reasons cows produce so much methane

is because of their specialized digestive tract.

It allows them to digest tough plant material

like grass, hay, and other vegetation.

Their stomach consists of four compartments.

The largest one, the rumen

acts sort of as a storage unit where food can sit and ferment.

Microbes in this area break down the food

using a process called enteric fermentation.

This process provides the animal with the nutrients and energy it needs

but it also produces methane as waste...

and the cow burps it out...

which makes the Earth a little bit hotter.

Here's the thing, though methane is literally waste...

and changing the diet of the cow can change

how much of it is produced.

Foods like grass or hay stay in the rumen longer

and produce more of it.

Whereas carbohydrate rich foods like corn produce less methane.

But the goal here isn't to completely change

the diet of all of these cows that we're feeding.

We can just tweak it a little.

We've been doing a lot of work on feed additives

to try to reduce synthetic methane emissions.

Ermias Kebreab is the associate dean at UC Davis

in the College of Agriculture and Environmental Sciences.

In 2018, he led a study that tested

how cows reacted to a certain additive...

Seaweed.

Specifically red seaweed.

Which grows naturally in tropical and subtropical ocean regions.

Back in 2016, researchers in Australia had found that sprinkling

the seaweed on cow feed could potentially reduce

methane emissions by over 95%.

And in 2021, Kebreab and his team were able

to replicate the study in live animals in California.

That completely blew my mind when I saw how effective it was.

The final results found that the seaweed could reduce

methane emissions by 82%.

At first I couldn't believe it because I...

I've never seen anything like that before.

And this specific species of red seaweed contains

high amounts of a compound called bromoform.

When a cow ingests it

it suppresses the enzyme that makes methane.

And the cows

they don't even notice the change in their dinners.

The seaweed is dried

and sprinkled onto the food they're used to.

They can still get all the nutrients they need.

Produce milk and grow.

But the waste is reduced.

Other additives work too, like fatty acids

which reduce methane by lowering the carbohydrate content

and reducing a specific parasite in the rumen known as protozoa.

And oregano was found to reduce

the number of bacteria in the rumen

to limit methane production.

But so far, out of all the additives tested

seaweed has been the most effective.

The best news is that scaling up the growth of seaweed

doesn't technically drain other resources

like fresh water or fertilizer...

since we can grow it in the ocean.

Growing seaweed could also combat other issues

like ocean acidification...

another climate problem caused by rising levels of carbon dioxide.

But there's still a lot of research left to do...

including figuring out how to dry it and package it

and ship it at a low cost.

Like, how do we effectively get seaweed

from a subtropical area to, say... Maine...

without adding tons of emissions with shipping?

That is, if you didn't know that seaweed is super heavy when wet.

But once we figure out the logistics, it's over.

We solved it.

The cows are content and the planet is saved.

Except not at all, obviously.

For one, this doesn't appear to be a one size fits all solution.

Recently, another Australian study

found that the same red seaweed only cut methane emissions by under 30%.

Now, granted, that's still a reduction, which is good news

but may be less of a miracle than we hoped.

Others are urging researchers to slow down on red seaweed

because of the bromoform .

In it's pure form, the EPA has reported

that it could be dangerous to human health

if ingested.

Luckily, studies so far haven't found that at dangerous levels in milk

or in meat from cows eating the seaweed additive.

But studies still need to be done

on how it might affect the cows long term.

So it's not a silver bullet...

but thankfully seaweed's not our only option.

I think this is just one of several solutions

that are being looked at at the moment.

And overall, there's a big push for change.

In 2021, 150 countries, including the United States

signed the United Nations Global Methane Pledge...

which aims to reduce methane emissions by 30% by 2030.

It's becoming more and more clear now that we won't get there...

unless we tackle enteric methane emissions.

In an ideal world, we'd have less livestock.

But getting people to change their habits

isn't always the most straightforward or quickest solution.

The work of searching for solutions to the climate crisis

needs to be multifaceted.

Within a year or two, you will see quite

a lot of different activities and different solutions.

That's going to come up.

And that could be one less cow burp at a time.