The 195 countries of the UN framework convention on climate change (UNFCCC) are meant to seal a pact to ensure warming is limited to 2C over pre-industrial times.
Laborious and complex, the talks have been dogged by finger-pointing between rich and poor countries over sharing the burden for curbing carbon emissions.
“Ambitious greenhouse-gas reduction proposals by the G7+EU states are central for a successful outcome in Paris,” said the CAT analysis.
“These countries are responsible in aggregate for around 30 percent of global greenhouse gases emissions and 40 percent of global GDP.”