A small but growing source of greenhouse gases is the group of refrigerant chemicals used in cooling systems in vehicles, homes, offices, and other settings. The United Nations Environment Programme says emissions from these substances now make up less than 1% of the world's greenhouse gas effects, but their use is expected to increase by an average of about 8% per year. By 2050 they could make up anywhere from 7-45% of all equivalent global CO2 emissions, depending on the projected scenario.
- "HFCs (hydrofluorocarbons): A Critical Link in Protecting Climate and the Ozone Layer,"  November 2011.
Refrigerants have already evolved numerous times in order to address certain problems that eventually became apparent. One of the major shifts was after global adoption of the 1987 Montreal Protocol on Substances that Deplete the Ozone Layer, which led to the phasing out of chlorofluorocarbons (CFCs) that are now essentially out of use.
One substitute has been hydrochlorofluorocarbons (HCFCs). Consumption has increased substantially since the 1960s, but is just beginning to slow down and possibly reverse. Since the late 1980s, HCFCs have generally been viewed as a transitional refrigerant, and the phase-out was accelerated in 2007.
A newer major class of replacement chemicals, hydrofluorocarbons (HFCs), has come into common use since the early 1990s, and is expected to be highly effective at reducing ozone impacts. But many HFCs (which also are used for a few things besides refrigeration, such as foam agents and fire retardants) also are very potent greenhouse gas sources.
To help make refrigerants less of a greenhouse gas problem, while still addressing ozone concerns, the UNEP report offers a range of recommendations, including use of HFCs with a very short atmospheric lifespan (days or weeks, instead of the dozens of years for a few HFCs now in use). Another recommendation is use of alternative substances such as ammonia, hydrocarbons, and dimethyl ether; however, some of these can create substantial toxicity or flammability problems, an issue the report acknowledges.
Other suggested remedies include widespread adoption of building siting and design criteria that reduce the need for air conditioning; changes in air conditioning systems so they perform more efficiently and effectively; and changes in manufacturing, maintenance, and disposal practices. Each of these might be effective, if properly done, but might also create problems of its own. For instance, HFCs with a short atmospheric lifespan can contribute more than long-lived HFCs to localized increases in ground-level ozone and other toxic breakdown byproducts.
Your reporting on this issue can range from the local to the global scale.
Coverage in your local area can include a focus on local refrigerant manufacturing plants, safe handling and disposal of refrigerants, black markets for refrigerants being phased out, building codes, planning and design practices (both old school and cutting edge), and public perceptions of the problem and solutions.
State and national issues include incentives and regulations for use of less harmful refrigerants, issues related to phasing from one generation of refrigerants to the next, and more comprehensive approaches to understanding the problems (including non-greenhouse gas issues) and crafting solutions.
Global issues include the relative role of refrigerants in climate change (and adapting to climate change, which involves more use of air conditioning in some settings); the role of various countries in contributing to and solving the refrigerant problem; global sources of chemicals, minerals, and other substances needed to make the current and next generations of refrigerants and the equipment in which they're used; and coordination of global agreements that address the ozone layer, climate change, toxicity, and other issues linked with refrigerants.
For one example of media coverage of the report, see:
- "Ozone-Safe Refrigerant Chemicals Add to Climate Danger,"  Environment News Service, Nov. 21, 2011.
A number of products and end users are mentioned in the report, providing starting points for you to identify sources. Among the many other sources you can contact on this issue are:
- American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Position Documents  (Climate Change, Natural Refrigerants, and Ammonia as a Refrigerant); media. 
- Air-Conditioning, Heating, and Refrigeration Institute  (US manufacturers); members. 
- Recycler's World, Coolants and Refrigerant Recycling Category. 
- EPA-Certified Refrigerant Reclaimers. 
- EPA, Stratospheric Ozone Protection and Climate Change. 
- EPA, Stationary Refrigeration and Air-Conditioning. 
- EPA, Motor Vehicle Air Conditioning. 
- EPA, Black Market CFCs/HCFCs and You: A Criminal Combination ; Enforcement Actions under Title VI of the Clean Air Act. 
- Center for Climate and Energy Solutions (begun in November 2011 as the successor to the Pew Center on Global Climate Change), High Global Warming Potential Gas Abatement. 
- Rep. Henry Waxman (D-CA) and Rep. Edward Markey (D-MA), April 3, 2009, letter to President Obama  requesting regulation of HFCs through revision to the Montreal Protocol.
- National Institute of Building Sciences, "Whole Building Design Guide: Landscape Architecture,"  May 28, 2010.
- American Society of Landscape Architects, "Combating Climate Change with Landscape Architecture,"  2011.
- Urban Land Institute; Climate Change, Land Use, and Energy.