Dairies Call on Legislators to Support Composting, Pasturing for Methane Reductions

Click to view the letter.
Click to view the letter.

California is moving full steam ahead in its efforts to reduce greenhouse gas emissions from the dairy sector. A state emissions-reduction strategy, released last week, proposes to slash the amount of methane released from dairy manure by 75% over the next fifteen years.

Achieving these considerable climate benefits, according to the Air Resource Board’s (ARB) Proposed Short-Lived Climate Pollutant Reduction Strategy, will require changes to the management of over one million California dairy cows. It will also require significant investment in a diversity of methane reduction strategies.

In response, a group of prominent dairy producers and processors have submitted a letter [click to view] to legislators calling for investment in manure management strategies that go beyond anaerobic digester technologies. This request is consistent with the basic conclusion of ARB’s new analysis, which suggests that we must pursue a variety of approaches – from composting to pasturing to digesters – in order to make a meaningful dent in dairy methane emissions.

The new document from ARB, posted online last week, represents a notable shift from an earlier draft released for public comment in fall 2015. That draft emphasized the use of expensive dairy digester technologies – which convert manure into bioenergy – as the primary way forward. Unfortunately, however, digesters require significant up-front costs, can burden dairy operators with considerable management and maintenance demands, and have an unproven track record in California: despite years of federal and state efforts to promote these technologies, only about a dozen digesters are currently operational in the state. Recently, dairies have been stressed to make digesters pencil out financially in other parts of the country, as well.

In response to stakeholder feedback and its own analysis, ARB now advocates a healthy mix of strategies that “will depend on dairy-specific factors and vary across the State.” This aligns with CalCAN’s recommendations, as submitted to ARB in a policy memo entitled Diversified Strategies for Reducing Methane Emissions from Dairy Operations.

However, Governor Jerry Brown’s budget proposal, released in January, would invest $35 million of the state’s climate change funds solely in dairy digesters – a tack that now runs counter to the state’s own proposed strategy.

Today, the Western Organic Dairy Producers Alliance, Stonyfield Organic, Organic Valley, and a dozen individual dairy operators submitted their letter to members of the Senate and Assembly Budget Committees, promoting a $5 million investment in pasture-based dairying, dry scrape, composting, and solid separation strategies, in addition to dairy digesters.

As the revised ARB strategy notes, California currently has higher per-milking-cow methane emissions than almost any other state, largely due to the common practice of ‘flushing’ dairy manure into liquid storage lagoons. Manure stored in lagoons decomposes anaerobically, generating significant amounts of methane. By contrast, manure from pastured cows decomposes aerobically in the field, thereby avoiding methane emissions altogether. Manure handled in ‘dry’ systems that do not rely on lagoon storage can also largely avoid generating methane by composting the waste stream, generating a valuable soil amendment.

For these reasons, ARB now suggests that converting away from flush water lagoon systems – the current standard amongst large confinement dairies in the Central Valley – may be among the least-risk, lowest-cost ways to diminish dairies’ current contributions to climate change. These conversions could also have additional environmental benefits, such as improved air and water quality, in some of the most heavily-polluted areas of the state.

As the state doubles down on methane emissions in pursuit of its climate change goals, CalCAN encourages policymakers to work closely with dairy producers from across the amazing diversity of that industry. Only by doing so can we truly achieve the transformative changes needed for agriculture and our environment.

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