Rethinking air conditioning amid climate change

Rethinking air conditioning amid climate change

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It was a monumental day for the environmental movement more than 30 years ago when the 198 countries of the world agreed on something for the first and only time. They signed the Montreal Protocol, making a pact to phase out a list of chemicals that damage the Earth’s ozone layer. Chief among these were chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons used by the cooling and refrigeration industry. Alternatives, such as hydrofluorocarbons (HFCs), were quickly found.

But in recent years, scientists have realized that the 1987 Montreal Protocol may have traded an immediate problem for a long-term one. Although HFCs do not cause the same damage to the ozone layer as CFCs, the chemicals have a warming potential hundreds to thousands of times that of COtwo—making its growing global use a cause for concern.

The industrial revolution of the 20th century saw a huge boom in the air conditioning and refrigeration industry in Europe and North America. Now, as developing nations boost their economies, countries like China, India, and Nigeria are seeing skyrocketing demand for these appliances.

According to a 2020 report from the United Nations Environment Program, about 3.6 billion refrigeration appliances are used, to cool buildings and refrigerate food and other items, such as medicines; the number is expected to rise to 9.5 billion by 2050. What’s more, that number would be 14 billion if everyone who needed refrigeration services could afford them, according to one estimate.

well-known magazine spoke with Shelie Miller, an environmental engineer at the University of Michigan School of Environment and Sustainability. Miller co-authored a paper in 2021 Annual Review of Environment and Resources which examined the growing global demand for cooling and refrigeration, its effects on greenhouse gas emissions, and potential solutions. This conversation has been edited for length and clarity.

This may sound like a strange topic to many people. Why should we care about the cooling and refrigeration industry?

When people think of the environmental impacts that need to be addressed, they rarely think of refrigeration services. But it’s an incredibly important topic that’s not really being addressed. “Refrigerated service” is a very broad category that refers to temperature-controlled environments. And it intersects with the construction, transport and food sectors. It has a tremendous impact when you start looking at global energy use and greenhouse gas emissions.

And the industry is poised to see exponential growth in developing countries. Therefore, it is important that we realize the overall impact of the industry.

How does the cooling and refrigeration industry affect the environment?

Cooling a room, whether it’s a home refrigerator or an air conditioner, requires a tremendous amount of energy. Because our power grids rely heavily on fossil fuels, any energy use that goes toward lowering temperatures also emits greenhouse gases. Much of the environmental impact is simply the consumption of an incredible amount of energy, much of it based on fossil fuels.

Also, when we talk about cooling space technology, it requires something called refrigerants. Refrigerants are chemicals used to lower temperatures and conventional refrigerants often have a high global warming potential.

So even though we’re using a relatively small amount of refrigerants, the impact of the refrigerants as they leak into the atmosphere ends up having a big impact on the climate.

We once used refrigerants like CFCs that had a devastating impact on the ozone layer. So we banned them and introduced new chemicals. Do we just trade problems here?

One of the great environmental successes is the banning of certain chemicals that deplete the ozone layer. As you mentioned, one of the major environmental conventions, the Montreal Protocol, banned the use of ozone-depleting chemicals in the refrigerant industry. As a replacement, we came up with hydrofluorocarbons or HFCs. And that did a great and effective job of reducing ozone depletion, but at the cost of warming.

So we trade ozone depletion potential for high greenhouse gas emissions. In another international agreement called the Kigali Amendment, nations are trying to address problems associated with greenhouse gas emissions from refrigerants. So now we are trying to have alternative refrigerants that also have lower global warming potential.

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