Is it accurate to equate the climate impact of methane emissions with the impact of carbon dioxide ? In other words , are there important differences in the nature of these emissions ?
So , this is one of those questions where I have to refer back to the beginning of our conversation and say ( that ) I ’ m not an expert in this particular thing . And this is a topic that is rapidly evolving in the science community . So , to hit on some of the high points , there ’ s a difference between the carbon dioxide and methane in how they react within the atmosphere . So , carbon dioxide is considered a stock gas , which means it hangs around in the atmosphere once it ’ s produced for a very long time — somewhere in the neighborhood of 1,000 years . Methane , on the other hand , is considered a slow gas , which means that it only hangs out in the atmosphere for about 10 years , and then it ’ s broken down through a process called hydroxyl oxidation . So , putting that in the context of a big picture — and why this has become a hot topic within agriculture in particular is that plants take up carbon dioxide and carbon sources from the environment . That ’ s something we all learned in school , generally . And those plants store that carbon and complex types of molecules , like carbohydrates , etc . So , when these plants , then , are consumed by animals in agriculture , those carbon-based molecules are broken down . And in a cow , some of that is converted to methane and released again into the atmosphere . But if that methane is then broken down in 10 years into carbon dioxide , some portion of our carbon dioxide is taken up by plants . And this cycle just continues again and again . So , if we ’ re not significantly increasing the amount of methane we ’ re putting back into the atmosphere in comparison to the amount we ’ re taking out , then perhaps we ’ re a little more carbonneutral than we thought we were , at least in that particular aspect of our carbon footprint . Now , there ’ s a lot more to that discussion than my very simplified overview right there . It is very much a current topic of debate and discussion within agriculture and within climate science . And it is one that I ’ ll be keeping an eye on , for sure , for the next few years .
Well , you ’ re right . I ’ m wondering if there ’ s a danger that this increasing clamor for a reduction in livestock emissions might upstage the effort to reduce the use of fossil fuels .
I think that ’ s a very good conversation to have , and it ’ s a touchy topic , Tom . I mean , in true scientific fashion , again , I ’ m going to say , “ It depends .”
So , as I said before , does agriculture contribute ? Absolutely . Do we need to reduce that contribution ? If we can , yes . Do fossil fuels contribute ? Again , absolutely . Do they need to reduce their contribution ? Certainly . But when we start equating those things by simply saying , “ They ’ re both contributors ,” that ’ s where it gets difficult , because — as I said before — the contribution coming from livestock and agriculture is significantly less than the contribution that ’ s coming from transportation and energy sectors that are largely fossil fuel-based . But when you put that to someone as far as what they can do in their everyday life to reduce their personal impact , it ’ s much easier to say , “ Well , I ’ m just not going to eat meat one day a week ” than it is to say , “ Well , I ’ m going to stop using my car one day a week .” Those are two very different lifestyle changes , and one is going to be far more approachable to most people .
Pollution from the really large farm operations runs off into streams that feed into major waterways like the Chesapeake Bay , the Great Lakes and the Gulf of Mexico . And that contributes to algal blooms , dead zones that impact drinking water supplies , aquatic ecosystems , recreation and people ’ s livelihoods . What ’ s your perspective on these large-scale operations ?
I think this is another one of those areas , Tom , that is a touchy subject but also an incredibly important subject . There is no doubt that agricultural runoffs contribute to all of these dead zones and issues with our water quality throughout the world , but it is one of those places where it is very important , again , to look at contribution . And unfortunately , I don ’ t have those numbers right in front of me , because I ’ ve not seen them . This is not an area that I ’ ve spent a lot of time looking into as a scientist , but I do know that , well , agricultural runoff is significant . There is the more recent research coming out of Duke University in North Carolina that ’ s looking at dead zones in urban streams , and what they ’ re finding is that those exist there as well . And so , we have to really start examining not only agriculture ’ s contribution to these issues but , also , our urban footprint , you know . One thing I paid attention to for years and tried to look at on my own property is the use of salt and ice melt , because I used salt as a weed killer . But when I use salt as an ice melt in the winter , that salt is staying in the environment , contributing to my grass not growing or contamination of my soil around my own property . And when we think about that scaled up to a global issue , of how much salt and other ice melt-type products we put on to roadways , and where does that ultimately end up , and what is it affecting as far as the environment around us — again , I don ’ t want to downplay agriculture ’ s contribution , because we absolutely do have an agricultural contribution — but there are other factors that come into this issue of dead zones , water quality and soil loss . And I know that within agriculture , farmers are constantly looking at adding buffer zones , changing the way they plant , changing the way they kill ( weeds ) — using precision farming to really only get the nutrients where they need to be when they need to be there so that we are minimizing that loss or leaching . And I think they ’ re doing everything they can as the information and technology becomes available . And that ’ s really all we can ask .
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