Has there been a substitute to CFC?Is CFC still used nowadays?

Answer 1

Long Answer:

CFCs are chlorofluorocarbons that were great for refrigeration because they were very inert and non-toxic. That means they would float around after a leak and never hurt people. Until they got to the upper atmosphere where they would catalytically destroy ozone, which protects us from the sun's uv rays and helps minimize things like skin cancer.

After this was discovered, about 20-30 years ago, eventually a worldwide ban was instituted. While many developing economies cheat, in the past 5-10 years atmospheric levels of CFCs have started going down, although it can still take 50-100 years for the ozone levels to go back up. However, the original problem remains--you want compounds with certain properties that are very non-toxic to use in refrigerants. The non-toxic part is very important because all refrigerators and air-conditioners constantly leak. So people started using HFCs--hydrofluorocarbons (no chlorines in them). They break down before they get to the ozone layer, so they don't deplete ozone.

On the other hand, they are ~100 times more effective at being a greenhouse gas than carbon dioxide. This means they could potentially really aggravate global warming. In case you're wondering how bad global warming is, it is now predicted that the polar ice caps will melt by 2040. I hope you don't live in coastal Florida. The European Union just (literally this week) instituted a ban on the most commonly used HFCs, and amusingly enough, it looks like the most likely substitute will just be carbon dioxide itself.

Short Answer:
There's a worldwide ban on CFCs although there's some cheating in developing nations. The alternative is HFCs although the European Union just banned them and it's likely other countries will follow suit.