Why We Must Stop Using Natural Gas
Methane emissions, the main component of natural gas and whose emissions EPA head Pruitt just eliminated from industry reporting requirements, may constitute the biggest GHG climate threat the planet faces.
Previous estimates have underestimated the severity of the green house gas threat posed by methane, the principal component of natural gas (around 85%). Methane emissions from natural gas leakage during oil and gas exploration and distribution, as well as emissions from animal feed lots and public waste facilities, threaten to help push global warming past the “tipping point” where unstoppable melting of frozen arctic soils could lead to catastrophic releases of naturally produced methane. To avoid this outcome, several steps should be taken. In particular, public policies that tout natural gas as a “bridge fuel” to cleaner energy should be understood as completely misguided.
Electric utility companies (load serving entities) should move quickly to help their customers switch their home heating fuels from fossil fuels (natural gas, heating oil, propane) to electricity. New high efficiency heat pump water heaters plus ducted or ductless heat pump systems are readily available that can replace natural gas water heaters, furnaces, and boilers . Moreover, such systems are easy to install, offer improved living environments, and are rapidly coming down in price. They combine with rooftop or community supplied solar energy to create ultra-low emission homes and commercial buildings.
Background of the Problem
Because methane, CO2, water vapor and other green house gases (GHGs) remain in the atmosphere for different lengths of time, scientists calculate their combined effects over an arbitrary time frame, usually 100 years. This allows, for example, the effects of the gas HFC-134, a refrigerant used in automobile air conditioning systems (13 year atmospheric life), to be summed up with the effects of other gases like carbon tetraflouride (atmospheric life 50,000 years). Scientists have used the term “global warming potential” (GWP) to describe the characteristics of each gas individually. The GWP compares each gas to carbon dioxide (CO2). The result is a number that indicates the climate changing effect of the gas when compared to CO2 over a 100 year span. Nitrous oxide, for example, has a GWP of 298, meaning it has 298 times the global warming effect of carbon dioxide over 100 years.
The serious flaw in this approach comes from the short term effects of common gases that remain in the atmosphere for only a few days or a few years, and represent a danger not considered in the arbitrary 100 year time frame used to measure combined GHG effects. Methane, the other big GHG besides carbon dioxide, remains in the atmosphere for about 10 years, so combining it with CO2 and other gases into a 100 year time frame effectively smears out methane’s actual short term effects. Methane is second only to CO2 as a man made contributor to warming, but it is increasingly the focus of scientific attention because of its short term threat to push the planet past a tipping point, where global warming may increase rapidly due to natural positive feedback loops. Two such feedback loops cause considerable concern. One is the vast amount of natural methane that will be released into the atmosphere as arctic soils warm, methane that will be created from long frozen biological carbon in the ground (mainly frozen plant matter). Another feedback comes from a warming atmosphere that can hold more water vapor, itself an extremely potent green house gas. As air warms its ability to hold more water vapor (more humidity) drives more warming.
Given these short term dangers, policy makers should take methane’s effect over its 10 year atmospheric presence into consideration, not simply the 100 year time frame that is still widely applied. In a 10 year time frame, methane is known to be about 100 times as powerful as CO2 as a green house gas, not the 28 to 36 times figure that is still used to guide public policies.
It is important to note that since the industrial revolution worldwide oil and gas development, large scale agriculture, and other factors have caused the absolute amount of methane in the atmosphere to not only go up about 250% (Figure 1), but to continue to increase even though its atmospheric life is only ten years. This strongly indicates that the sustained increase over the last three centuries has been caused by human activities, and thus can be reversed.
It is important to note that since the industrial revolution worldwide oil and gas development, large scale agriculture, and other factors have caused the absolute amount of methane in the atmosphere to not only go up about 250% (Figure 1), but to continue to increase even though its atmospheric life is only ten years. This strongly indicates that the sustained increase over the last few centuries has been caused by human activities, and thus can be reversed.
Notice how worldwide atmospheric methane appears to have leveled out around the year 2000 and then started increasing again around 2008. A great deal of scientific debate has centered on this development. Some scientists argue that the new increase is primarily due to increases in emissions from the tropics, from wetlands, or from agricultural sources. However, recent research points to natural gas recovery and distribution as the main source of increased emissions. This research points to shale fracturing, which expanded rapidly around the year 2008, as a primary driver of newly rising methane levels worldwide
Underestimating the global warming effect of methane is common when setting public policy. Below a chart indicates the estimated sources of green house gas emissions in Sonoma County, California (Source: Action Plan 2020 by the Regional Climate Protection Authority, Sonoma County). Notice that the amount of GHG emissions from the “Building Energy” sector is estimated at 33% of total emissions.
Building emissions in this chart are derived almost entirely from natural gas consumption. Moreover, solid waste emissions and a substantial portion of livestock emissions are methane as well, leading to a total of at least 40 percent of reported emissions to be methane. In this report the multiplier used for calculating building emissions was considered to be 28 times that of CO2. Clearly, if the true short term methane to CO2 GWP ratio is closer to 100 in the short term, then the effect of natural gas emissions should occupy a much larger fraction of the pie chart. Whether relatively more resources should be spent on reducing transportation CO2 emissions, as opposed to methane emissions, rests largely on the reliability of such assessments.
It should be clear why some scientists have argued that total methane emissions, including agricultural emissions, may represent as big or bigger a green house gas threat in the short term as do CO2 emissions from all other sources, including the transportation sector.
These facts point to the need to rapidly move away from natural gas as a fuel used for heating buildings and water, and the adoption of renewable energy for those purposes. Public agencies and utility companies must recognize the imperative of this clean energy transition away from natural gas to newer, cleaning technologies powered by renewable energy.