Europe must stop selling new petrol, diesel and conventional hybrid cars by 2028 in order to stand a better chance of honouring the Paris Agreement’s most ambitious target, according to a new study.

Research conducted by the German Aerospace Centre, commissioned by Greenpeace Belgium, says that passenger car engines as we know it need to be completely phased out from new sales before the end of the next decade.

Otherwise, Europe will struggle to “meaningfully contribute” to limiting global warming to 1.5 degrees Celsius, the most ambitious part of the Paris Agreement on climate change’s “well below 2 degrees Celsius” overall aim.

Green activists have now urged governments to adopt effective phase-out regimes, so that existing fleets can be replaced in good time, according to Euractiv.com.

The study provides two clear options for meeting the 1.5 degrees goal: one uses a so-called carbon budget that means there will be a 50% chance of hitting the target, while another assumes a more ambitious 66%. A carbon budget is the amount of CO2 we can emit before global warming takes effect and pushes the planet over a certain average temperature.

In the one-in-two chance scenario, the findings insist that unchecked passenger car emissions will eat away the carbon budget for staying under 1.5 degrees within a decade.

For the more ambitious 66% likelihood, the news is even more grim as the budget will be exhausted within just five years if business-as-usual continues.

The German Aerospace Centre study authors concluded that those figures show either “stringent” CO2 cuts to passenger cars are necessary or further cuts in other sectors have to be identified.