Biogas is a gaseous renewable energy source produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste, wastewater, and food waste. Biogas is produced by anaerobic digestion with anaerobic organisms or methanogens inside an anaerobic digester, biodigester or a bioreactor. The gas composition is primarily methane and carbon dioxide and may have small amounts of hydrogen sulfide, moisture and siloxanes. The gases methane and hydrogen, can be combusted or oxidized with oxygen. This energy release allows biogas to be used as a fuel; it can be used in fuel cells and for heating purpose, such as in cooking. It can also be used in a gas engine to convert the energy in the gas into electricity and heat.
Ruminants are hoofed herbivorous grazing or browsing mammals that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microbial actions. The process, which takes place in the front part of the digestive system and therefore is called foregut fermentation, typically requires the fermented ingesta to be regurgitated and chewed again. The process of rechewing the cud to further break down plant matter and stimulate digestion is called rumination. The word "ruminant" comes from the Latin ruminare, which means "to chew over again".
Burping is the release of gas from the upper digestive tract of animals through the mouth. It is usually audible.
The agricultural emissions research levy was a controversial tax proposal in New Zealand. It was first proposed in 2003 and would collect an estimated $8.4 million annually from livestock farmers, and which would have been used to fund research on the livestock industry's emissions of greenhouse gases, to further the nation's compliance with the Kyoto Protocol.
Climate change mitigation is action to limit climate change by reducing emissions of greenhouse gases or removing those gases from the atmosphere. The recent rise in global average temperature is mostly due to emissions from burning fossil fuels such as coal, oil, and natural gas. Mitigation can reduce emissions by transitioning to sustainable energy sources, conserving energy, and increasing efficiency. It is possible to remove carbon dioxide from the atmosphere by enlarging forests, restoring wetlands and using other natural and technical processes. Experts call these processes carbon sequestration. Governments and companies have pledged to reduce emissions to prevent dangerous climate change in line with international negotiations to limit warming by reducing emissions.
A carbon offset is a reduction or removal of emissions of carbon dioxide or other greenhouse gases made in order to compensate for emissions made elsewhere. A carbon credit or offset credit is a transferrable financial instrument (i.e. a derivative of an underlying commodity) certified by governments or independent certification bodies to represent an emission reduction that can then be bought or sold. Both offsets and credits are measured in tonnes of carbon dioxide-equivalent (CO2e). One carbon offset or credit represents the reduction or removal of one ton of carbon dioxide or its equivalent in other greenhouse gases.
Environmental vegetarianism is the practice of vegetarianism that is motivated by the desire to create a sustainable diet, which avoids the negative environmental impact of meat production. Livestock as a whole is estimated to be responsible for around 15% of global greenhouse gas emissions. As a result, significant reduction in meat consumption has been advocated by, among others, the Intergovernmental Panel on Climate Change in their 2019 special report and as part of the 2017 World Scientists' Warning to Humanity.
Enteric fermentation is a digestive process by which carbohydrates are broken down by microorganisms into simple molecules for absorption into the bloodstream of an animal. Because of human agricultural reliance in many parts of the world on animals which digest by enteric fermentation, it is the second largest anthropogenic factor for the increase in methane emissions directly after fossil fuel use.
The United States produced 5.2 billion metric tons of carbon dioxide equivalent greenhouse gas (GHG) emissions in 2020, the second largest in the world after greenhouse gas emissions by China and among the countries with the highest greenhouse gas emissions per person. In 2019 China is estimated to have emitted 27% of world GHG, followed by the United States with 11%, then India with 6.6%. In total the United States has emitted a quarter of world GHG, more than any other country. Annual emissions are over 15 tons per person and, amongst the top eight emitters, is the highest country by greenhouse gas emissions per person. However, the IEA estimates that the richest decile in the US emits over 55 tonnes of CO2 per capita each year. Because coal-fired power stations are gradually shutting down, in the 2010s emissions from electricity generation fell to second place behind transportation which is now the largest single source. In 2020, 27% of the GHG emissions of the United States were from transportation, 25% from electricity, 24% from industry, 13% from commercial and residential buildings and 11% from agriculture. In 2021, the electric power sector was the second largest source of U.S. greenhouse gas emissions, accounting for 25% of the U.S. total. These greenhouse gas emissions are contributing to climate change in the United States, as well as worldwide.
Livestock's Long Shadow: Environmental Issues and Options is a United Nations report, released by the Food and Agriculture Organization (FAO) of the United Nations on 29 November 2006, that "aims to assess the full impact of the livestock sector on environmental problems, along with potential technical and policy approaches to mitigation". It stated that livestock accounts for 18% of anthropogenic greenhouse gas emissions, a figure which FAO changed to 14.5% in its 2013 study Tackling climate change through livestock.
A low-carbon diet is a diet with low greenhouse gas emissions. Choosing a low carbon diet is one facet of developing sustainable diets which increase the long-term sustainability of humanity.
The environmental impacts of animal agriculture vary because of the wide variety of agricultural practices employed around the world. Despite this, all agricultural practices have been found to have a variety of effects on the environment to some extent. Animal agriculture, in particular meat production, can cause pollution, greenhouse gas emissions, biodiversity loss, disease, and significant consumption of land, food, and water. Meat is obtained through a variety of methods, including organic farming, free-range farming, intensive livestock production, and subsistence agriculture. The livestock sector also includes wool, egg and dairy production, the livestock used for tillage, and fish farming.
Atmospheric methane is the methane present in Earth's atmosphere. The concentration of atmospheric methane—one of the most potent greenhouse gases—is increasing due to methane emissions, and is causing climate change.
The environmental impact of agriculture is the effect that different farming practices have on the ecosystems around them, and how those effects can be traced back to those practices. The environmental impact of agriculture varies widely based on practices employed by farmers and by the scale of practice. Farming communities that try to reduce environmental impacts through modifying their practices will adopt sustainable agriculture practices. The negative impact of agriculture is an old issue that remains a concern even as experts design innovative means to reduce destruction and enhance eco-efficiency. Though some pastoralism is environmentally positive, modern animal agriculture practices tend to be more environmentally destructive than agricultural practices focused on fruits, vegetables and other biomass. The emissions of ammonia from cattle waste continue to raise concerns over environmental pollution.
Asparagopsis taxiformis, formerly A. sanfordiana, is a species of red algae, with cosmopolitan distribution in tropical to warm temperate waters. Researchers have demonstrated that feeding ruminants a diet containing 0.2% A. taxiformis seaweed reduced their methane emissions by nearly 99 percent.
Asparagopsis is a genus of edible red macroalgae (Rhodophyta). The species Asparagopsis taxiformis is found throughout the tropical and subtropical regions, while Asparagopsis armata is found in warm temperate regions. Both species are highly invasive, and have colonised the Mediterranean Sea. A third accepted species is A. svedelii, while others are of uncertain status.
Karen Beauchemin is a federal scientist in Canada who is recognized as an international authority on methane emissions and ruminant nutrition. Her research helps develop farming techniques that improve how we raise cattle for meat and milk, while reducing the environmental impacts of livestock production.
Increasing methane emissions are a major contributor to the rising concentration of greenhouse gases in Earth's atmosphere, and are responsible for up to one-third of near-term global heating. During 2019, about 60% of methane released globally was from human activities, while natural sources contributed about 40%. Reducing methane emissions by capturing and utilizing the gas can produce simultaneous environmental and economic benefits.
FutureFeed is a seaweed-based feed ingredient for livestock that is currently being developed by a team from Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO). The primary component of FutureFeed is dried Asparagopsis, a genus of red algae, which has been shown to reduce the methane (CH4) emissions of ruminant livestock by up to 99%. It is added to fodder at feedlots in dosages of 1-2% dietary intake to achieve this result. FutureFeed is currently being developed in collaboration with James Cook University (JCU) and Meat and Livestock Australia (MLA), with the primary goal of scaling for mainstream commercial use.
The amount of greenhouse gas emissions from agriculture is significant: The agriculture, forestry and land use sector contribute between 13% and 21% of global greenhouse gas emissions. Agriculture contributes towards climate change through direct greenhouse gas emissions and by the conversion of non-agricultural land such as forests into agricultural land. Emissions of nitrous oxide, methane make up over half of total greenhouse gas emission from agriculture. Animal husbandry is a major source of greenhouse gas emissions.
