Around 150 countries have agreed to limit the use of hydrofluorocarbon (HFC) greenhouse gases in an attempt to protect the Earth's climate. <br/><br/>Used in refrigeration and air conditioning, HFCs play a growing role in increasing global temperatures. <br/><br/>The developed nations have commited to decreasing their use of the chemicals sooner than poorer countries. <br/><br/>US Secretary of State John Kerry told delegates in Rwanda yesterday that HFCs are disastrous for the climate.