Europe Rolls Out Vision for a Carbonless Future, but Big Obstacles Loom

That proposal, which would be gradually introduced from 2023, has not been welcomed by many countries that trade with Europe, including the United States. If passed, it could be challenged in the World Trade Organization.

The hundreds of pages of proposed laws — which the Commission has called “Fit for 55,” a slogan that some have joked would better suit a yoga studio — will be sharply debated and inevitably amended before becoming binding on the 27-member bloc.

There are concerns that the poor will pay an inequitable share of the cost of decarbonization and that it will be seen as an elite project, prompting more political backlash from populist parties and groups, like the 2018 “yellow vest” protests over a climate-related increase in French gasoline prices.

But without the new legislation, said Simone Tagliapietra of Bruegel, a Brussels-based economic think tank, Europe would have reduced its emissions only 60 percent by 2050, rather than reaching carbon neutrality.

The 12 legislative proposals presented on Wednesday are designed to reduce reliance on fossil fuels including coal, oil and natural gas; to expand the use of renewable-energy sources including solar, wind and hydro power to at least 38.5 percent of all energy by 2030; to force the faster development of electric cars with much tighter CO2 limits and hope to end the sale of all internal-combustion cars by 2035; and to support clean-energy options for aviation and shipping, which are prime polluters. For the first time, a carbon market will be established for road transportation and buildings.

Transportation and buildings respectively account for 22 percent and 35 percent of all E.U. carbon emissions, Mr. Tagliapietra said. But creating a separate market for them will be politically difficult, because it will increase fuel costs for families and small and medium businesses, he said.

The European Union is “the first large economy in the world to start translating climate neutrality ambition into real-world policy action,’’ he said. “But if there is one principle that should be guiding the negotiations over the next two years, this certainly is the principle of climate justice.”