Methane emissions have seen the largest annual spike since systematic measurements began, having doubled from 2020-2021 alone.
Climate models and international agreements typically consider methane’s warming impact over 100 years, according to climate scientist Jessika Trancik. But that may not be an accurate way of looking at it.
Wetlands
Wetlands can both capture and store carbon, while emitting greenhouse gases like methane (CH4) and nitrous oxide (N2O), making their impactful global distribution crucial to understanding their role in climate change – this is particularly relevant when looking at natural wetlands, which account for about one third of anthropogenic methane emissions.
The relationship between wetland CH4 flux and climate change is complex, and research studies have reported variable results. Some evidence indicates that wetlands respond to climate anomalies by altering methane production and release rates; such responses could result from changes to abiotic factors like temperature or water availability, or biogeochemical processes like methane oxidation and denitrification processes.
Methane gas in wetlands is produced through decaying vegetation, animal waste and human activities like farming or fossil fuel use, making it one of the more potent greenhouse gases with a warming impact 28 times greater than carbon dioxide.
Rising temperatures and precipitation levels are leading to methane emissions from wetlands being released into the air, while melting permafrost contributes to swamps, marshes and bogs releasing more of it into the atmosphere. Without action taken to limit human-caused greenhouse gas emissions by 2100, natural methane emissions could increase by as much as 80% by 2100.
Wetlands play an essential part in the global water cycle and are home to an abundant diversity of species. Not only do they provide food and shelter for many living organisms, they are also invaluable water storage facilities that serve flood control measures as well as soil stabilization purposes.
Wetlands are also important carbon sinks, absorbing more carbon from the atmosphere and ground than they emit through emissions. Unfortunately, it can be difficult to ascertain their carbon uptake due to unknown global distribution and no standard methods for measuring GHG fluxes and incompatible statistical analysis between studies that increases uncertainty.
Oil and Gas
Oil and gas industry emissions are one of the main contributors of methane emissions worldwide. Some emissions come from natural sources, such as melting Arctic permafrost or leaky pipelines; but most come from human activities; for instance, one natural gas well blowout may release as much methane within 24 hours as all annual human emissions from multiple European countries combined!
Recent years have witnessed increased attention paid to methane abatement efforts, such as measurement campaigns and new technologies such as satellite instruments capable of detecting methane plumes. According to estimates by the Congressional Budget Office (CBO), methane emissions from oil and gas activities in the United States have declined since 2012. Yet overall energy demand and fossil fuel production has since returned above pre-crisis levels.
Short-lived climate pollutants (SLCPs) are one of the major obstacles to keeping global average temperature increases below 2degC, as per an international partnership initiative called Climate and Clean Air Coalition to Reduce Short-Lived Climate Pollutants which comprises of 69 governments as well as more than 200 civil society organizations and companies. Furthermore, C40 Cities Climate Leadership Group with their Clinton Climate Initiative Cities program collaborate on efforts to help urban areas reduce these pollutant through waste management improvements or other means.
Emissions from the oil and gas sector are determined by both extraction rates of natural gas as well as active oil wells. Over time, methane emissions per unit of natural gas produced have declined over time in most major production regions with Permian Basin being an exception where methane intensity is expected to increase rapidly before declining after 2017.
The US Environmental Protection Agency’s annual inventories demonstrate that oil and gas emissions decreased from 2010 to 2019, before increasing again after 2017, likely driven by production spikes. An analysis of satellite and surface observations reveals larger-than-reported year-to-year variations in US methane emissions that are most likely the result of changes in production rates, active well counts, or new wells being drilled.
Agriculture
Agriculture produces massive amounts of methane and nitrous oxide emissions that contribute to global climate change. Furthermore, changes to carbon storage in soil and vegetation can have serious ramifications on Earth’s ability to absorb greenhouse gasses.
Agriculture accounts for two-thirds of human-linked methane emissions; livestock — especially cows and other ruminants — contribute the vast majority. Their digestive tracts contain microorganisms that digest plant material into energy for fuel; their digestive systems also break down grasses, leaves and high fiber byproducts from crops to produce methane more than other animals that eat grains; this contributes to higher methane emissions than animals that rely more heavily on grains as food sources. As populations rise globally and economic development drives increased demand for animal proteins from livestock species worldwide, so will their impact be compounded.
Scientists have made great strides toward decreasing methane emissions from cattle and other ruminants. By increasing digestible energy content of animal feed, methane intensity can be reduced by one third; also producing more milk or meat per animal reduces emissions significantly. Other simple and cost-effective strategies may include providing them with additional fiber or changing feed types to lower methane intensity.
Farmers have also begun collecting and using manure to reduce methane emissions, although their actions are less widespread than reducing grazing pressures or improving irrigation. One major challenge facing farming is using flooded fields that prevent oxygen from penetrating soil layers, creating conditions conducive to methane-producing bacteria – this practice is one major cause of China’s high methane emissions, contributing to climate change by shifting carbon ecosystem balances.
One effective method for reducing methane emissions from agriculture involves the implementation of methane fees. These could be charged based on either cropland area or livestock operation size; fees would help cover costs associated with decreasing emissions while encouraging farmers to produce more from plants than livestock, or switch over to more efficient systems.
Reducing methane emissions from agriculture requires holistic strategies that consider all aspects of production. For instance, incentives to monetize manure via anaerobic digestion may decrease emissions from ruminants but fail to address other sources of human-linked methane production.
Waste
Methane is the second-most significant greenhouse gas contributor to climate change after carbon dioxide. On a 100-year timescale, methane’s global warming potential exceeds that of carbon dioxide by 28 times, and 84 times on a 20-year timeframe.
Methane emissions can be quickly reduced to reduce global warming, but this requires clear plans and buy-in from businesses, governments, and communities impacted by these emissions.
Landfills are one of the major sources of methane gas emissions, produced when organic waste such as food scraps, wood chips and paper decay in these sites. Methane can be released at different rates by individual cells within landfills–making its source difficult to pinpoint.
In the US, for instance, more than 40 percent of landfills do not yet have methane gas collection systems in place. A new study finds that these systems are critical in lowering emissions of methane gas into streams and rivers; soil conditions, land-water connections, human activity that disrupts river networks all play a part.
While methane emissions from natural sources such as wetlands, livestock, oil and gas drilling operations, coal mining operations, stationary combustion facilities, mobile combustion units and wastewater treatment plants account for a substantial share of methane emissions, the majority of it comes from fossil fuel use and built environments such as landfills – an immediate solution that can have profoundly positive results when implemented with vulnerable communities.
There is one mainstay: the humble but essential cigarette. But have no fear – today there are other, less obvious forms of tobacco consumption, too! Last month, the UN’s seminal report on climate change stated that rapid cuts to methane emissions and other greenhouse gases can help mitigate some of the most severe consequences of warming by keeping temperatures from increasing by more than 1.5 degrees Celsius above preindustrial levels – one of the key aims of Paris agreement. Given the urgency of this task, implementing a methane fee that builds on existing business taxes could be an effective means of curbing methane emissions that harm human health and the environment. RMI is working closely with its global partners to identify key mechanisms for cutting methane emissions and create data products to inform actionable emission cuts, including Carbon Mapper who are developing an airborne monitoring system to track landfills from above.
