In mid-August 2022, the Inflation Reduction Act, the largest investment initiative in U.S. history to reduce greenhouse gas emissions, was passed.

The Inflation Reduction Act also includes measures to reduce the burden of health care costs as well as measures to combat climate change, such as the introduction of clean energy. A scienceinsider article in Science summarizes the challenges of climate action in the context of U.S. agriculture.　

The North American prairies were originally blessed with some of the world's most fertile soils, but excessive tillage has released soil carbon into the atmosphere. In particular, large amounts of greenhouse gases are being emitted in areas that were originally wetlands and in areas where forests have been converted to farmland. When combined with the way soil is tilled, the use of chemical fertilizers and fuel-intensive agricultural machinery, and the raising of livestock, which emit large amounts of methane, agriculture accounts for about 10% of the greenhouse gas emissions in the United States. In light of this situation, the U.S. Congress has set out to wind back the clock and begin attempting to put some of the carbon back into the soil.

The new law will reportedly allocate $25 billion to protect forests and promote climate-friendly agricultural practices. Among other things, it aims to maintain soil health by promoting soil conservation practices through no-till agriculture and cover crops. Reducing nitrous oxide from chemical fertilizers and methane emissions from livestock is also important.

On the other hand, the extent to which these practices help reduce GHG emissions depends on the actual interactions among crops, added organic matter, and microorganisms (which can also emit GHGs) for each particular soil type and environment, and may take many years before any real benefits are realized (during which time the practices may be (and even interruptions in the practice in the meantime), and there is still uncertainty involved. In any case, the goal is to shift agriculture to a new paradigm in which these environmentally regenerative practices become the norm. In order to realize this paradigm shift, it is necessary to build reliable national greenhouse gas emission inventory and estimation models, and to steadily collect data and accumulate evidence on how much carbon sequestration is possible through conservation practices.

Despite the growing need for an urgent global response to climate change, the circumstances surrounding agriculture in each country and region are different: the Americas, Europe, Africa, South America, and the Asian monsoon regions. Therefore, the causes of greenhouse gas emissions in the agricultural sector in all countries and regions are different, and therefore there is no one-size-fits-all technical approach to reducing greenhouse gas emissions. On the other hand, a paradigm shift toward sustainable agricultural practices is becoming an inevitable trend worldwide, and it will be important to learn from the lessons of each country and region.

Reference

ERIK STOKSTAD Can farmers fight climate change? New U.S. law gives them billions to try: Cutting emissions from fertilizer and livestock will be key, scientists say 16 AUG 2022 https://www.science.org/content/article/can-farmers-fight-climate-chang…

Contributor: IIYAMA Miyuki (Information Program)