Climate Change For Dummies. Elizabeth May

Чтение книги онлайн.

СКАЧАТЬ the paddy, which is a perfect airless environment for creating methane.

      All cows, pigs, chickens, and other farm animals account for the rest. The food breaking down in their stomachs produces methane that they, shall we say, emit into the air — one way or another. All animals emit methane — yes, even you — but livestock’s methane causes a problem because there are so many of these fairly big animals.

      Humans also add methane to the atmosphere through treating wastewater and from landfills — all that garbage spews methane into the air while it breaks down.

      People also use methane as a fuel. Natural gas is 90 to 95 percent methane, and when natural gas is extracted from the ground, some methane escapes into the air.

      Methane stabilized for a while — still it didn’t

      Methane levels in the atmosphere had stabilized at 1.8 parts per million, but since the first printing of this book, record growth in methane has been experienced globally. In 2021, smashing previous records methane grew to 1.9 parts per million.

      Much of this increase was due to the use of novel technology (referred to as hydraulic fracturing or fracking) to get gas out of bedrock formations like shale. The boom in natural gas fracking has accelerated the move away from coal by electric utilities in the United States and Canada. But it isn’t clear win for the climate. (Read more about using natural gas as a fuel in Chapter 4.)

      Fracking threatens water quality with chemical contamination, and research has shown that it has even caused in increase in earthquakes. Turning the Earth into a pincushion has some worrying side effects: The process of fracking bombards the bedrock formations with jets of water, containing special chemicals to get the gas out of the substrate and into pipelines headed to making liquified natural gas (LNG). The process of fracking uses so much energy that even though using LNG for energy at the end point is relatively clean, the so-called upstream (or process of extraction of LNG) has the same GHG impact as burning coal.

      

A lot of methane is frozen into the ground of the Arctic, trapped by the permafrost (any ground that remains completely frozen for more than two years). Rising northern temperatures, however, are melting the soil. When the Arctic land thaws, it becomes swampland — and it starts dishing out methane like hotcakes. We look at this problem in greater detail in Chapter 7.

      Nitrous oxide (N₂O)

      The amount of nitrous oxide (N₂O) in the atmosphere is even smaller than the amount of methane, but it accounts for about 7 percent of the overall greenhouse effect. The greenhouse effect of nitrous oxide per unit is almost 300 times more potent than that of carbon dioxide. This gas is actually still going up at a rate of 1 part per billion (ppb) each year — as of 2018, it was at 331 parts per billion. Increasingly, nitrous oxide comes from human activities.

      The following are ways nitrous oxide appear in the atmosphere:

       In agriculture, farmers encourage those natural bacteria to produce more of the gas through soil cultivation and the use of natural and artificial nitrogen fertilizers. The biggest source of nitrous oxide, natural or human-made, is fertilizers used in agriculture. Fertilizers count for 60 percent of human-made sources and 40 percent of sources overall.

       Ocean- and soil-dwelling bacteria produce nitrous oxide naturally as a waste product.

       Dentists use nitrous oxide as an anesthetic. (Laughing gas is nitrous oxide — not so funny now, is it? Though it’s in such small amounts that you don’t need to worry about your root canal adding to global warming.) Industrial processes (to create nylon, for example) also produce nitrous oxide.

       Humans add a lot of nitrous oxide to the atmosphere by using automobiles. Ironically, cars produce the gas as a side result of solving another environmental problem — see the nearby sidebar for the scoop.

      Hexafluoro-what?

      Hydrofluorocarbons. Perfluorocarbons. Sulfur hexafluoride. Try saying those names three times fast. They’re as hard to say as they are effective at trapping heat. These three types of gases are all human-made and don’t exist naturally in the atmosphere. They come from a number of different industrial processes that create air pollution.

      Almost all car air-conditioning systems use the 13 hydrofluorocarbons (HFCs). (We look at how industry emits these GHGs in detail in Chapter 5.) Most of the seven perfluorocarbons (PFCs) are by-products of the aluminum industry. Sulfur hexafluoride (SF₆) comes from producing magnesium, and many types of industry use it in insulating major electrical equipment.

      HOW GOOD INTENTIONS INCREASED NITROUS OXIDE EMISSIONS

      Fossil fuels (which we discuss in greater detail in Chapter 4) contain nitrogen. When cars burn gasoline, they give off the nitrogen-based chemicals nitrogen monoxide (NO) and nitrogen dioxide (NO₂) — together known as NO_x gases. These NO_x gases create acid rain and smog in cities.

      In response to these environmental problems, governments in North America forced car companies to put catalytic converters in all their cars. Catalytic converters convert smog-causing chemicals into other chemicals that aren’t as damaging to our lungs and don’t cause acid rain.

Unfortunately, these catalytic converters turn NO_x gases, which don’t have an effect on climate change, into nitrous oxide (N₂O), which does! (One more reason, if you need it, why everyone should drive less.)

      Other players on the GHG bench

      The two GHGs that we talk about in the following sections do play a role in climate change, but they aren’t on the United Nations list of 24 GHGs and get left aside in most discussions about the impact of GHGs on global warming — not for scientific reasons, but because of decisions made in international negotiations.

      Water vapor

      As we discuss in the section, “Focusing On Carbon Dioxide: Leader of the Pack,” earlier in this chapter, water vapor is a huge player in the greenhouse effect. As shocking as it may seem, good ol’ H₂O (two parts hydrogen, one part water) causes the majority — 60 percent — of the planet’s greenhouse effect. But the ramped-up threat of climate change isn’t tied to water vapor. Water vapor remains an essential reason the planet is warm enough to sustain current life forms.

Unlike the production of the other GHGs, humans don’t directly cause the increase of water vapor. But the other gases that are produced heat up the atmosphere. When plants, soil, and water warm up, more water evaporates from their surfaces and ends up in the atmosphere as water vapor. A warmer atmosphere can absorb more moisture. The atmosphere will continue to absorb more moisture while temperatures continue to rise. See Figure 2-6.

СКАЧАТЬ