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Global Warming: The Rise of Methane

Mon ,15/02/2021


Greenhouse gases play a huge role in keeping the surface of the Earth warm. Without the greenhouse effect, the temperature of the Earth would average about -18°C, and all the water on the Earth’s surface would be ice. The average temperature of the Earth’s surface is now about 15°C and rising. The graph below shows the concentration of the main greenhouse gases in the Earth’s atmosphere, and how they have changed in the last two millennia. 

Inarguably, an increase in the greenhouse gas concentrations will warm the Earth – and we are seeing that happen. The average temperature of the Earth is now 1.2°F warmer than it was in 1850. The temperature of the Earth was fairly constant over the thousand years before the industrial age, and people, plants, animals, and our agricultural practices have adapted to that temperature. What will happen as the Earth’s temperature rises? We are finding out, and the effects are alarming.

Of the greenhouse gases, water accounts for about 70% of the greenhouse effect, carbon dioxide about 20%, methane 4%, nitrous oxide 1%, and the other greenhouse gases together about 5%. Our efforts to reduce global warming have focused mostly on carbon dioxide, as its concentration has increased over 40% from our use of fossil fuels. It will take time to phase out fossil fuels and transition to the use of renewable energy. The concentration of methane has grown appreciably in the last century, from about 800 parts per billion (ppb) to over 1900 ppb and it is rising rapidly. Methane has about an eight year half-life in the atmosphere before it is converted to carbon dioxide by natural process. The methane in the atmosphere would decrease quickly if we stopped putting it there. That is important, as methane has about 72 times the global warming potential of carbon dioxide.

The main cause of the rise in methane is commercial leaks, oil production, and fracking operations. In commercial sales, it is sometimes less expensive to ignore small leaks than to fix them. But many small leaks add up and it has been estimated that about 10% of natural gas put into pipelines is lost before it reaches the end user. Some of those problems could be fixed. Methane is also produced as a byproduct of oil production. If the amount of gas is too small to be sold commercially, it is often flared, i.e., lit like a torch. That converts it into carbon dioxide, which is less damaging to the environment. 

Fracking operations now produce a tremendous amount of natural gas for commercial use, and considerable amounts of methane escape into the atmosphere from the drilling operations and pipeline leaks. It requires effort and resources to contain the methane at the wellhead and to fix storage and transmission leaks. The EPA requires that leaks be self-reported, but often they were just ignored. Just recently, it has become possible to detect methane from GHGSat satellites. Below is a map that shows eight leaks in a 25 mi.² area in Turkmenistan, as they were seen by satellite. Estimates were that those leaks accounted for about 10,000 kg of methane a day. The methane was from fracking operations, pipeline leaks, and unlit flares.

Before satellites, most methane emissions were discovered by infrared cameras. Using them, it was found that the methane emissions from the Permian basin in Texas and New Mexico were much greater than those reported. Much of that came from unlit flares, which could easily be corrected. One accident at a gas well in Ohio is now thought to be the largest methane leak ever in the United States. Three different oil and gas facilities in Algeria were found to be leaking methane amounts equivalent to the carbon dioxide produced by a medium-size coal-fired power plant. The detection of leaks has been spotty and regulation of leaks has been difficult in the past. There is considerable economic incentive for gas companies to reduce methane emissions from leaks. However, it is expensive to send out crews to detect and repair smaller leaks, and many companies have just let them go.

The EPA expects the oil and gas industry to self-report and to repair leaks, but many companies just don’t. There are plans to deploy seven more GHGSat satellites to monitor greenhouse gas emissions. With them, it will be possible to detect and enforce the regulation of many methane leaks. It has been estimated that cutting methane emissions by 40% would have the same effect as taking 60% of the world’s coal-fired power plants off-line. And, we could easily cut methane emissions by 40% within the next decade.

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