Kill the refrigerators, slow down climate change?

First, there were chlorofluorocarbons, or CFCs. These chemical compounds were used liberally in spray cans, solvents, and many other products, until we figured out that the giant hole in the ozone layer—which, you know, keeps us alive—was probably due to CFCs. So we replaced them with similar chemicals known as HCFCs, and more recently, with hydrofluorocarbons, or HFCs. Those spray cans now tend to lack any of these halocarbons (the overall class including CFCs, HFCs, and others), but we still make our refrigerators and air conditioning units with HFCs.

We started doing that to save the ozone layer. Mission accomplished, but with caveats: HFCs are incredibly powerful greenhouse gases, meaning they are contributing to global warming. Many now think that phasing out HFCs over time is a smart idea; HCFCs are scheduled for a phase out by 2030, based on the environmental treaty known as the Montreal Protocol. But phasing HFCs out, it seems, won’t be enough: we’ve got to kill your refrigerator.

A new study published in the journal Atmospheric Chemistry and Physics shows that by using HFCs in refrigerators and AC units, we are “banking” the HFC emissions for the future. Instead of a quick release in a spray aerosol can, most of those appliances will eventually let the HFCs leak out and continue to do damage even long after we stop manufacturing the stuff. A lot of damage.

First of all, HFCs are remarkably potent greenhouse gases. You may have heard how methane, leaking out of natural gas pipelines and from other sources, is around 25 times as strong as carbon dioxide when it comes to heating up the planet. Essentially that means the gas is better at trapping heat, and HFCs blow methane out of the water. Some of these gases are more than 10,000 times as strong a warming agent as carbon dioxide, while others more commonly used still beat out CO2 by 1,400 times.

But okay, just the fact of HFCs’ potency isn’t enough to worry us. The increase in demand and use, however, should. The U.S. Environmental Protection Agency is certainly worried: this year, along with Canada and Mexico, the E.P.A. helped submit a proposal to add a phaseout of HFCs to the Montreal Protocol, citing the rapid increase in demand. They point out that HFC emissions increased by eight percent each year between 2004 and 2008, and their use is expanding largely due to increased demand for refrigeration in developing countries.

So what happens if this sort of trend continues? The new study found that if we just continue manufacturing HFCs as we are now, their contribution to warming will increase dramatically. By century’s end, the radiative forcing could reach 0.5 watts per square meter; that, essentially, a measure of the energy balance of the earth, where higher numbers mean we’re warming up. That number is almost three times as great as the current amount attributed to CFCs, HCFCs, HFCs, and all their cousins combined.

Another way of looking at it is in terms of CO2-equivalent tons of emissions. If we phase out HFCs in the year 2050, the “banked” gases in your fridge will add between 39 and 64 gigatons of CO2-equivalent emissions; that’s at least how much humans release from every source (cars, coal plants, forest burning, and so on) each year. If we could phase out the HFCs a lot earlier, by 2020, that number drops to only 9 gigatons of banked HFCs. In short, it would be like turning off all the world’s lights, cars, planes, and of course refrigerators, for a year and a half. In either case, again, the phaseout is just one piece: we need to actively collect and destroy all those appliances to keep the gases out of the atmosphere, a task that gets harder and harder as we build more of them, especially in developing countries. So, phase out sooner, and destroy what’s already made. The climate will thank us. – Dave Levitan | May 20 2014

Source: Velders GJM, Solomon S, Daniel JS (2014). Growth of climate change commitments from HFC banks and emissions, Atmos Chem Phys, 14, 4563-4572. DOI: 10.5194/acp-14-4563-2014.

Image:, BMJ