(Introduction):

Methane (CH4), like other gases that have been increasing in the atmosphere, are responsible for the greenhouse effect that leads to global warming and climate change. One source of this gas is cattle farming; however, methane has a relatively short half-life in the atmosphere.

(Objective):

Consequently, if methane lasts only few years in the atmosphere, what is the contribution to the atmospheric increase of this gas made by the national cattle herd? To answer this question, the present work was carried out.

(Methodology):

Firstly, the historical trend of enteric methane emission from the national cattle herd is described, and subsequently the net change of this gas in the atmosphere, product of bovine activity in Costa Rica, is shown. Based on national bovine population statistics, the emission of enteric methane was estimated for the national herd and according to bovine production system, using the methodology of the Intergovernmental Panel on Climate Change. Considering the half-life of methane in the atmosphere, calculations were made to estimate the change in atmospheric methane coming from the Costa Rican cattle herd.

(Results):

The results show that the national bovine population reached its maximum at the end of the 1980s; the behavior of enteric methane emission showed the same trend, varying according to the production system. The change in atmospheric methane because of the contribution from the national cattle herd showed to be incremental from 1940 to 1990, subsequently decreasing to remain stable from 2000.

(Conclusions):

It is concluded that in the last 30 years the Costa Rican cattle ranch has not contributed to the atmospheric increase of this gas.