"As an essential step toward this long-term reduction, the group of developed countries should cut their emissions to an average of 30 per cent below 1990 levels by 2020 under a new global climate change agreement," the commission said.
"The EU should take the lead by committing autonomously to reduce its own emission by at least 20 per cent by 2020."
The commission said the EU target would be increased to 30 per cent if other major industrialised powers also agreed to more cuts.
It said a 50 per cent reduction in emissions is needed by 2050 if temperatures are to rise no more than 2C, "which in turn should prevent massive and irreversible disruption of the global climate system".
Many industrial nations say that reducing greenhouse gases will impose extra costs on their economies and reduce growth.
The EU said that member nations should turn to greener forms of power to reduce their output of carbon dioxide and other harmful gases.
Jose Manuel Barroso, the EU Commission president, said that it was time for Europe to embrace a "low-carbon economy", in a speech to mark the initiative on Wednesday.
The EU says that 20 per cent of all its energy should come from renewable power by 2020 and 10 per cent of vehicle fuel from biofuels.