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Climate Change For Dummies. Elizabeth May
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Название: Climate Change For Dummies

Автор: Elizabeth May

Издательство: John Wiley & Sons Limited

Жанр: Биология

Серия:

isbn: 9781119703129

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FIGURE 2-6: Water evaporates and lingers in the atmosphere.

Water vapor also differs greatly from other GHGs because the atmosphere can hold only so much of it. When you watch a weather forecast, you hear the term relative humidity, which refers to the amount of water vapor currently in the atmosphere compared to how much the atmosphere can hold. On a really hot and sticky day, the relative humidity may be 90 percent — the atmosphere has just about taken in all the water vapor it can. When the relative humidity reaches 100 percent, clouds form, and then precipitation falls, releasing the water from the air.

Ozone depleters

Chlorofluorocarbons (CFCs) are also considered GHG, responsible for about 12 percent of the greenhouse effect the planet is experiencing today. You don’t find much of these CFC gases around anymore because the Montreal Protocol of 1989 required countries to discontinue their use. CFCs break down the ozone — the layer throughout the stratosphere that intercepts the sun’s most deadly rays. (Without the ozone layer, the sun’s ultraviolet rays would kill all living things.) CFCs were mostly used in aerosol spray cans and the cooling liquids in fridges and air conditioning. The Montreal Protocol was a fantastic success. The use of chemicals that destroy the ozone layer is illegal — globally. And now the ozone layer has started repairing itself! A side effect of banning ozone-eating chemicals is that a lot of them were also GHGs. So protecting the ozone layer also helped the climate!

Because CFCs are already regulated under the Montreal Protocol, they’re not regulated under climate agreements. The recent Kigali Amendment to the Montreal Protocol will remove a significant amount of GHG that are also ozone depleters (Read more about what gases are covered under the Kyoto Protocol in Chapter 11.)

RUNNING UP EMISSIONS WITH YOUR SNEAKERS

Some of the sources of these gases are really wild. Here’s one: Nike came out with the popular Nike Air shoe, a running shoe with a cool little air-filled bubble in the heel, in the late 1980s. That bubble was filled with — you guessed it — a GHG (Sulfur hexafluoride, to be exact)!

The amount of GHG in those shoes all together added an equivalent of about 7 million metric tons of carbon dioxide — or the emissions from 1 million cars — into the air when they hit the garbage dump after being worn out. In the summer of 2006, after 14 years of research and pressure from environmental groups, Nike stopped using the GHG in shoes and replaced it with nitrogen. We’re glad that bubble burst.

Unfortunately, getting sulfur hexafluoride out of Nike runners didn’t eliminate all sources. Sulfur hexafluoride levels in the atmosphere continue to rise due to its use in the electricity sector. Concentrations of sulfur hexafluoride have been creeping up by about 0.36 parts per trillion (ppt) per year. In 2021, it made up 10.66 ppt of our atmosphere.

Chapter 3

Recognizing the Big Deal about Carbon

IN THIS CHAPTER

Looking into what else contributes to climate change

Linking carbon dioxide to temperature trends

Understanding what happens when the temperature becomes too hot to handle

Limiting greenhouse gas emissions

Elizabeth and Zöe Caron wrote Global Warming For Dummies in 2009. Back then, the consensus of the world’s scientists was that

Climate change was caused by rising carbon and other greenhouse gases (GHGs) emitted to the atmosphere ss a result of human activity.

Climate change could become irreversible and catastrophic if emissions kept increasing.

The use of fossil fuels had to be reduced drastically.

The solid worldwide scientific consensus has only been reinforced since then. And now the consensus isn’t just among scientists — it has become common understanding. Humans are having real-time experiences of floods, fires, droughts, heatwaves, and other disasters. The worst-case projections for the speed and magnitude have turned out to be not worse enough.

Still, even though the science is settled, scientists still say global warming is a theory. A scientific theory is based on a set of principles that describe a particular phenomenon — Newton’s so-called “law of gravity” is properly called his “theory of gravity.” Theories aren’t technically facts, but sometimes theories become so strong that people accept them as facts.

But how do you know this theory of GHG emissions causing climate change is correct? Can you really trust all those bigwig scientists? And if it’s correct, what does this theory suggest is going to happen next? We answer those questions in this chapter.

Considering Other Causes of Global Warming

Sure, some uncertainty exists around exactly where the global climate system will hit tipping points in the atmosphere, how global changes will affect local weather, or how much of it is due to human activity. What if GHGs aren’t the only culprits behind climate change?

The climate is an incredibly complex system affected by the sun, cloud cover, and complex long-term trend. In this section, you read about possible other drivers for climate change and see why no other has nearly the effect of GHG emissions from burning fossil fuels.

The Intergovernmental Panel on Climate Change (IPCC) says that it’s 99 percent certain that increasing carbon dioxide levels due to human activity are the major cause of climate change. The IPCC says that there’s less than a 1 percent chance that climate change is being caused by natural factors.

So, although some uncertainty exists, the debate on the human contribution is largely settled. With that said, some natural climate change drivers need discussion. That’s largely because, over the years, these natural climate change drivers have been advanced to counter the growing consensus that human activity, primarily by burning fossil fuels and cutting forests, is the primary cause of dangerous changes in our global climate system. Putting the other natural culprits in the following sections aside is key to focusing on what humanity must do to preserve a habitable planet.

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