Refrigerants: pick your poison

Walk into any grocery store, big or small, and you’ll be met with walls of freezers and fridges working to keep your favorite foods fresh. A century ago, rudimentary refrigeration came from insulated rooms, filled with blocks of ice harvested in the winter months. Today’s refrigeration is much more sophisticated and reliable: behind these meticulously stocked shelves are kilometers upon kilometers of interwoven copper piping, carrying specific chemicals called refrigerants that keep everything cold.

While refrigerants are essential in keeping grocery stores running smoothly, they’re also amongst the most devastating compounds to the overall climate. In the 50s and 60s, refrigeration and air-conditioning systems were made from CFCs, otherwise known as chlorofluorocarbons, which have up to 15,000 times the global warming potential of carbon dioxide. That means that even the smallest amounts of these gasses can have important consequences to the planet’s health if they escape into the environment.

CFCs play a doubly damaging role in raising the planet’s global temperature. In the lower layer of the atmosphere, they trap solar heat and temperatures rise. In the upper layer of the atmosphere, they interact with the Earth’s protective ozone layer. Ozone is destroyed by CFCs through a series of chemical reactions, allowing a greater part of the sun’s UV rays to reach the planet’s surface. Global average temperatures rise even more, with devastating effects on human health and ecosystems in general.

Fortunately, scientists and policymakers were able to come to a swift consensus on CFCs. The 1987 Montreal Protocol effectively banned CFCs, which has allowed holes in the ozone layer to gradually repair themselves. The main hole – once larger than the size of Antarctica – is now closed, and the ozone layer is expected to be fully repaired by mid-century. Not only is this good news for the climate, but the United Nations estimates that this represents the prevention of millions of cases of cancer (especially skin cancers) and eye cataracts.

Solving the problem – harder than it seems

Phasing out CFCs but increasingly relying on refrigeration systems represented a need for alternative chemical refrigerants. These came in the form of HFCs (hydrofluorocarbons) and PFCs (perfluorocarbons). As the comparable names indicate, these halocarbons perform similarly, both in terms of refrigeration and potential environmental consequences. While HFCs and PFCs are generally seen as an improvement to their predecessors, they still have 3,000 times the global warming potential of carbon dioxide, on average. And they’re still able to cause damage to the ozone layer.

As modern commercial refrigerant systems, such as those found in grocery stores, leak around 25% of the refrigerants they contain each year, the environmental impacts of HFCs and PFCs can add up. Combine this with the effects of old canisters of CFCs, rusting away in back-country garages and releasing their contents, and it’s clear that improvements can be made.

Back to improved basics

Keeping things cold is a complicated science that relies on a select few high-performance molecules. Of these, we have environment-damaging halocarbons, and we have the original synthetic refrigerant: ammonia. Ammonia has global warming and ozone-depleting potentials of zero, is cheaper than halocarbons, and is extremely efficient at keeping temperatures low. With these benefits, why was it phased out in the first place?

There are two key disadvantages to using ammonia as a refrigerant. Firstly, ammonia is highly toxic to humans. In case of a significant leak, its distinctive smell does allow it to be easily detected, but early refrigeration systems simply couldn’t be trusted. Second: ammonia is not compatible with copper, an important material in the manufacture of pipes and wiring. Although the refrigeration systems we use today are impervious enough to avoid the risk of death from ammonia poisoning (despite their 25% annual leak rate), many grocery stores and industrial air-conditioning systems would have to completely overhaul their piping systems at a significant cost.

Still, some companies are choosing to take the initial financial hit, seeing ammonia as their best option in the long run. But ammonia isn’t the only alternative to the HFCs and PFCs used today, and we aren’t doomed to return to the days of refrigeration by ice block. Instead, others are choosing to invest in a new, almost counter-intuitive type of refrigerant – carbon dioxide itself.

Carbon dioxide is recognized for its harmful effects on the environment, and rightfully so. Yet its global warming potential pales in comparison to its aforementioned synthetic counterparts (global warming potential of 1), and it doesn’t destroy the ozone layer. While not ideal, carbon dioxide offers drastic improvements to our current refrigeration systems.

Once again, it’s a question of policy

Many Asian and European countries have already begun phasing out HFCs and PFCs in favor of carbon dioxide or ammonia-based refrigeration. On the other hand, barely 1% of the 40,000-some grocery stores in the United States have transitioned to halocarbon-free systems. The numbers aren’t much better in Canada, either. So, what’s the reason for these international discrepancies?

As is the case with most things environment and climate, the key to positive change lies in the hands of policymakers and politicians. Good legislation that forces the hand of the refrigeration industry has allowed Asia and Europe to be far ahead of North America in solving this problem. By introducing laws that make companies subject to fines for their continued use of HFCs and PFCs, it has become cheaper for companies to invest in new, more sustainable technologies. Positive change then comes sooner rather than later.

Fortunately, some good news is on the horizon. In April 2018, Canada introduced new legislation designed to cut the use of HFCs and PFCs by 85% by 2036. Once in power, the current American political administration swiftly followed suit: in 2021, the American Environmental Protection Agency passed a ruling to reach the same target by the same year. So long as these policies aren’t abandoned through changes in government, the refrigeration industry will be made more environmentally friendly in the coming years.

What can individuals do?

Besides petitioning your government for productive policy change, individuals can do the following to reduce the impact of CFCs, HFCs, and PFCs:

• Find out what kind of refrigerant is used at your local grocery stores. This website is a global, interactive database for this information. If the stores near you aren’t already listed, you can investigate for yourself. Industrial refrigeration cases are labelled with the type of refrigerant they use. Simply look for the sticker, make sure your phone’s geotagging option is enabled, snap a photo, and upload to the Climate Friendly Supermarkets database. Their team will add your information to the map, helping you and your neighbours figure out the most sustainably refrigerated grocery store in your area.

• If you’re in the market for a new fridge, freezer, or air-conditioning unit, look for halocarbon-free models. Also, make sure you’re disposing of your old appliances in a sustainable manner, when the time comes. You can find this information here.

• If you do have an old canister of CFCs hanging around, dispose of it properly! Not only will you be helping the planet, but you may be able to make a few bucks. Companies such as the Chicago-based Refrigerant Finders will buy CFCs and get rid of them in a safe and sustainable manner.

• Look for ways to reduce your need for refrigeration. Only use air-conditioning when absolutely necessary, opting for opening a window or using fans instead. Buy UHT milk – stable at room-temperature until opened due to higher pasteurization temperatures – instead of the milk from your grocery store’s refrigeration section. Don’t put hot foods directly in the fridge or freezer to cool down. Lastly, try to avoid generating food waste, so you can be sure that refrigeration wasn’t wasted on food destined to be thrown away.