Beyond US President Donald Trump’s decision in June to withdraw the United States from the 2015 Paris climate agreement, a more profound challenge to the global climate pact is emerging. No major advanced industrialized country is on track to meet its pledges to control the greenhouse-gas emissions that cause climate change.

Wishful thinking and bravado are eclipsing reality. Countries in the European Union are struggling to increase energy efficiency and renewable power to the levels that they claimed they would. Japan promised cuts in emissions to match those of its peers, but meeting the goals will cost more than the country is willing to pay. Even without Trump’s attempts to roll back federal climate policy, the United States is shifting its economy to clean energy too slowly.

The Paris agreement offered, in theory, to reboot climate diplomacy by giving countries the flexibility to set their own commitments. As of July 2017, 153 countries have ratified the agreement — 147 of which have submitted pledges to reduce emissions, also known as nationally determined contributions. The idea is that as each country implements its own pledge, others can learn what is feasible, and that collaborative global climate protection will emerge. That logic, however, threatens to unravel because national governments are making promises that they are unable to honour.