Global warming will leave coffee drinkers with a bitter aftertaste as it cuts usable coffee farming land in half by 2050, driving prices up and quality down.
The impact of extreme weather conditions could mean the amount of land farmable for coffee falls by as much as 50 per cent in a matter of decades, the Climate Institute says.
Coffee farming has already been affected by rises in temperatures and changes in rainfall in key coffee growing regions such as Mexico, Guatemala and Nicaragua.
"Consumers are likely to face supply shortages, impacts on flavour and aromas, and rising prices," Climate Institute chief executive John Connor said.
The knock-on effect of rising temperatures could mean farmers would be forced to higher ground, possibly coming into conflict with other land uses such as nature conservation and forestry, Mr Connor said.
The report, commissioned by Fairtrade Australia and New Zealand, also found that for the 25 million farmers around the world and their local communities any changes would be hard to adapt to as they lack the resources to do so.
But coffee drinkers can help by buying brands that are carbon neutral and which pay their farmers a fair wage, Mr Connor said.
"[Coffee drinkers can] demand climate action from the coffee companies and our governments to ensure all products, business models and economies are carbon or climate neutral," he said.