Are our cattle causing an increase in global warming

Authors: Rotz, Clarence - Al; HRISTOV, ALEX - Pennsylvania State University

Submitted to: Northeast Pasture Consortium Annual Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 2/11/2019
Publication Date: 2/19/2019
Citation: Rotz, C.A., Hristov, A. 2019. Are our cattle causing an increase in global warming[abstract]. Northeast Pasture Consortium Annual Meeting Proceedings. p. 1.

Interpretive Summary: No Interpretive Summary is required for this Abstract. JLB.

Technical Abstract: The short answer to this question is no, but this requires some explanation. Cattle do produce a lot of methane gas, primarily through enteric fermentation in their rumen and fermentation in their manure. Methane is a powerful greenhouse gas that, along with nitrous oxide, carbon dioxide and some other compounds in the atmosphere, create a blanket around our planet to keep us warm. Our current problem is that our blanket is thickening. Over the past decade, we have seen the media place a lot of blame on cattle for greenhouse emissions and their impact on climate. For cattle here in the U.S., this has been misleading at best. The methane that cattle produce is part of a natural carbon cycle that has been happening since the beginning of life on our planet. This methane is oxidized in the atmosphere through a chain of reactions. Within about 10 years of its release, over 90% of the methane is removed from the atmosphere with the carbon in the methane ultimately transformed back to carbon dioxide. This replaces the carbon dioxide that was originally drawn from the atmosphere and fixed in crops to produce feed. In contrast, when we burn fossil fuels, we are taking carbon that has been stored in the earth since pre-historic times and converting it to “new” carbon dioxide released to the atmosphere where it will be with us for 1000s of years. So, whereas cattle are part of a natural cycle with short term impact, burning of fossil fuels has a much more permanent impact. The other consideration is that cattle numbers are not increasing, so the amount of methane they produce is not increasing. Looking further back, cattle today are not contributing a substantial increase in the methane emissions from U.S. lands compared to the ruminants (primarily buffalo) on the land in pre-settlement times. The fact remains that cattle produce a lot of methane. This methane is essentially wasted energy escaping the rumen. Reducing this waste by increasing the efficiency of the rumen may provide a substantial benefit by producing more meat or milk with less feed consumed. Dietary changes and feed supplements can reduce enteric methane emissions and improve feed efficiency. So, although cattle in the U.S. are not really contributing to the increase in global warming and related climate change, they may become part of the solution by reducing the greenhouse gas they produce.