Professor Robert B. Jackson: 3. Finding invisible methane

3. Finding invisible methane

Professor Jackson also placed a priority on methane. Methane is an extremely powerful greenhouse gas that has a far greater warming effect than carbon dioxide for the same amount emitted. Global warming potential (GWP) is used as an index to show this impact. For example, viewed over a 20-year period, methane has roughly 90 times the warming power of carbon dioxide. Furthermore, methane increases ozone (which causes photochemical smog) near the ground through chemical reactions in the atmosphere, and may exert a negative impact on our health. In addition, the concentration has been increasing at a significantly faster rate than that of carbon dioxide.

Methane is largely classified into methane from natural sources and methane from human activities. Methane from natural sources includes emissions from wetlands, thawing permafrost, and volcanic activity. One natural source that Professor Jackson has paid particular attention to is tropical wetlands such as those in the Amazon. In tropical regions, the speed with which the number of methane-producing microbes expands increases along with rises in temperature. As a result, more methane is released into the atmosphere. Although these emissions come from natural sources, they are also influenced by human-caused global warming.

According to recent estimates, methane emissions from natural sources account for only 1/3 of the Earth’s total emissions, and the remaining 2/3 arise from human activities. This includes leaks during the extraction of natural gas, livestock, especially cattle through belching, bacteria in flooded rice paddies, waste landfill sites, aging city gas lines and devices, and more.

During the past 10 years, Professor Jackson has focused on methane emissions from homes and other buildings in large cities in the United States. He has measured methane that escapes from household gas appliances and pipelines, because leaks of methane from structures had not yet been clarified. Professor Jackson says, "Turning on a methane appliance such as a cooking stove or water heater at home is like standing behind a car’s exhaust pipe and breathing the exhaust."

His research showed that, on a CO₂-equivalent basis, the amount of methane that leaks from cooking stoves in homes throughout the United States is comparable to the emissions from nearly 500,000 gasoline-powered cars.

4. To restore the atmosphere