04/20/2012 05:11 pm ET Updated Jun 20, 2012

Wild Seafood: An Unlikely Key to Combating Climate Change

Here's some food for thought on this upcoming Earth Day: Agriculture is the leading contributor to greenhouse gas emissions in the world. It even beats out transportation. The food we raise, especially meat like pork, beef and chicken, is contributing more to climate change than the cars and SUVs that clog our freeways. That's not to say we should let our gas guzzling habits off the hook, but it does mean that we should look at our carbon footprint holistically -- including the food we consume.

But people must eat. And we need protein, right? So really, this conversation isn't worth having unless there's another option, another animal protein out there that contributes less to global warming. Well, guess what? There is.

It's called wild seafood.

Before we can fully understand the benefits of this undervalued food source, it's important to dissect the impact that pork, beef, poultry, and lamb have on our already stressed planet.

Let's break down the numbers. On average, Americans eat nearly 275 pounds of meat per year. We're number two world-wide -- Denmark is number one, at an incredible 321 pounds of meat per capita. Pork is the most popular meat worldwide, followed by poultry and then beef. The U.S. is home to around 60 million pigs and they produce more than 21 billion pounds of meat each year. The world's largest slaughterhouse, in North Carolina, processes 32,000 pigs per day.

In order to raise these pigs, they must be fed. And like all living things, what goes in must come out. This waste alone releases vast amounts of greenhouse gases into the atmosphere -- a potent mix of 60 to 70 percent methane and 30 to 40 percent carbon dioxide. Methane traps twenty-three times more heat in the atmosphere than carbon dioxide and that's one of the reasons why agriculture is the world's single biggest contributor to global warming. We're not talking about a little waste here, either. The 10 million pigs in North Carolina for instance, create more sewage than the residents of North Carolina, California, Pennsylvania, New York, Texas, New Hampshire, and North Dakota combined. Most of this waste isn't processed. It's kept in open-air lagoons that pump out greenhouse gases into the atmosphere like it's going out of style.

The McKinsey Institute has estimated that we'll need to increase water and land availability by 140 and 250 percent, respectively, in the next two decades to meet the growing demand for food. Doing so -- with our business as usual model that includes processing incredible amounts livestock -- won't be cheap or good for our Earth. Meeting this demand would pump 66 gigatons of carbon dioxide into the atmosphere, which could cause temperatures to rise by five degrees Celsius in the next eighty years. Even an increase in temperature at a fraction of that would devastate regions where poor farmers rely on rain-fed agriculture to feed their families.

But we can drastically improve our chances of battling climate change if we start thinking seriously about wild seafood. Unlike land-based agriculture, wild seafood requires no arable land. It requires only minimal traces of fresh water in processing and produces significantly less CO2 than pigs or cows or chickens. Better yet, it is truly one of the world's most renewable resources. It doesn't take a million years to replace fish, like coal or oil. Wild seafood, properly managed, can replenish itself year by year, decade by decade, millennia by millennia.

The potential that wild seafood has to feed the world, however, isn't something we can take for granted. Despite the resiliency of our oceans, we've done a terrible job at keeping them healthy and abundant. We are literally fishing our oceans into oblivion -- catching fish more quickly than they can reproduce to support their populations, destroying ocean nurseries and habitat, not controlling bycatch. As a result, global fish catch has declined since the late 1980s despite more and more boats on the water. Seafood can be a healthy, low-impact protein, but only if we are good stewards of the oceans.

On Earth Day, it's important to remember that our blue planet can still help to sustain us, if we let it.