It turns out that the single most significant way to reduce CO2 emissions is to change the way we keep ourselves, and our food, cool. That's according to Project Drawdown, an organization working to identify, research and model the top solutions to climate change. But what makes cooling such a significant contributor to a warming planet? Refrigerators and air conditioners work by using chemicals to absorb and release heat, and while ozone-damaging CFCs and HCFCs have been largely phased out, their replacement -- HFCs -- are a climate change disaster, with a "1,000 to 9,000 times greater capacity to warm the atmosphere than carbon dioxide." 

But as the stories in this collection (see below) demonstrate, people around the world are coming up with diverse and innovative solutions for keeping things cool. From district energy systems in Malaysia to  storing snow in Japan and Sweden, to a zero-energy brick and charcoal fruit cooler in Kenya, technologies exist around the world for sustainably maintaining cold. This solution is one of the Drawdown Ecochallenge actions to reduce greenhouse gas emissions.

click here for more stories on climate solutions in the Solutions story tracker. 

1. Why is Refrigerant Management such an important tool in fighting climate change?
2. Explain what a district heating system is.  How does it work in principle?
3. Describe the potential economic benefits of alternative ways of cooling, especially regarding cash crops in developing countries.
4. How can storing snow lead to summer air conditioning?  How does climate change affect the concept of snow storage?
5. Does your campus have a refrigeration management policy through Facilities Management?  What is it?  How do they dispose of campus refrigerant? What are the other energy policies in place on your campus? What might you and your peers in this class do to influence these policies?
6. Properly disposing of refrigerators and air conditioners in homes when they need replacing is a significant action individuals can take to avoid contributing to climate change. Does your home have air conditioning, or your dorm room or apartment? How old is the unit or system?  Is it properly maintained to avoid leaks? What about the refrigerator? Explore the climate change impact of these appliances and what you can do to reduce it.

1. Full implementation of the Refrigeration Management goals would result in the reduction of almost 90 gigatons of CO2, making it the most extensive reduction in all of Project Drawdown.  Over 30 years, containing 87% of all refrigerants would achieve that 90 gigaton figure.  In October 2016, officials from more than 170 countries met in Kigali, Rwanda, to negotiate a deal to address this problem.  The goal is to phase out HFC's in wealthy countries by 2024 and in developing countries by 2030.  If the Kigali Accord was fully implemented, that would result in additional carbon reductions between 25 and 78 gigatons, a huge figure.  Scientists estimate the Kigali accord will reduce global warming by nearly one degree Fahrenheit. Additionally, there are new refrigerant substitutes already on the market, including natural refrigerants such as propane and ammonium.
2. Unlike conventional air-conditioning and heating systems, district energy systems consist of a network of underground pipes that pump hot or cold water to multiple buildings in a district, neighborhood or city. They are able to use larger sources of heating and cooling, such as waste heat from power stations, which cannot be connected to a single building.  According to UN Environment,  transitioning to district energy systems can help cities to reduce their primary energy consumption for heating and cooling by up to 50 percent. They also form the central infrastructure for many cities’ 100 percent renewables or carbon neutral targets.
3. By using charcoal and brick refrigeration systems, rural farmers in tropical countries can keep their produce fresh for up to 15 days longer, greatly extending their opportunity to sell the produce.  The systems are relatively cheap to produce, and pay for themselves within a short period of time.  These systems also relieve stress on the supply chain, giving farmers extra time to transport and store their goods.  With the addition of waxing techniques, these farmers are now able to convert a much higher percentage of their crop to profit.
4. In far northern climates such as Canada, Scandinavia, and Russia, storing snow and converting it to cooling in warmer months is a viable opportunity.  Snow is abundant and free, although there are energy costs to storing it.  Much of the power of this strategy, however, comes from a combination of factors; since air conditioning (refrigeration) is the single largest factor in climate change, any strategy that replaces it serves a disproportionately high return on investment.  Snow is relatively cheap to store now, but it remains to be seen whether this strategy will lose efficacy as climate change adversely affects Arctic snow cover.
5. Answers will vary.
6. Answers will vary.