A replica of the Statue of Liberty by Danish artist Jens Galschiot emits smoke in a park outside the 23rd U.N. Conference of the Parties climate talks in Bonn, Germany, on Nov. 17. (Martin Meissner/AP)

The recent round of U.N. climate negotiations ended Friday in Bonn, Germany. While no important decisions were made on climate finance — transfers from wealthy to poor countries to support climate mitigation and adaptation — the question of who pays for global climate gave rise to heated debates.

Formally a technical meeting to finalize the design of the 2015 Paris agreement on climate change, the summit was the first after President Trump’s June 2017 announcement to withdraw from the deal.

Trump’s decision leaves the United States alone outside the Paris agreement. While U.S. noncooperation shouldn’t deter other countries from pledging climate action, my recent research with Thijs Van de Graaf shows that it threatens industrialized countries’ promises of climate finance for mitigation and adaptation in poorer countries.

The overall Paris framework will probably survive without the United States

The basic idea of the Paris agreement is pretty simple. Each country pledges action to lower its carbon footprint, and countries together review everyone’s efforts every few years. For example, a country could pledge to reduce carbon dioxide emissions by a certain amount by the year 2030 or promise to double the share of renewable energy in power generation. The hope is that over time countries increase their ambition level so that they can reduce their greenhouse gas emissions and we all can avoid rapid climate change.

Trump’s withdrawal is unlikely to directly threaten this growing ambition. The entire world — and much of the United States — is behind the Paris agreement, and the cost of clean energy is falling. With solar power, electric vehicles and more, inexpensive opportunities to reduce greenhouse gas emissions are expanding.

But the U.S. absence will take a real bite out of funding for climate mitigation

However, Trump’s withdrawal can threaten future cooperation through another channel. If the United States refuses to finance climate mitigation and adaptation in developing countries, then industrialized countries will have a hard time keeping their promise to offer $100 billion in climate finance every year from 2020.

These funds would support renewable energy, energy efficiency, forest conservation and other projects that reduce greenhouse gas emissions. The money would also help poorer countries adapt to the consequences of climate change. For example, climate finance could fund levees to protect cities from flooding.

In 2014, the United States offered about $2.7 billion in climate finance, a sum comparable with contributions from Germany and France. With the Trump administration refusing to contribute, other industrialized countries will face great difficulties in putting together enough funds.

There’s a real risk that developing countries will no longer trust the governments of the industrialized world on climate issues. The broken promise could poison climate negotiations in the future.

Besides spurring disagreement and bad faith in negotiations, a failure of climate finance would also threaten future pledges under the Paris agreement. The governments of many developing countries, such as the Philippines, have promised to adopt ambitious measures conditional on financial assistance.

If U.S. noncooperation means that funds dry up, these conditional promises have little value. The lack of U.S. climate finance leaves a wide gap, and other industrialized countries will have a difficult time convincing their citizens that they should step in.

In the future, growth in greenhouse gas emissions is more likely to come from developing economies than from industrialized countries. The combination of economic growth and larger populations means that energy demand will grow in countries that are still poor, and some of that demand might be met with fossil fuels. If U.S. noncooperation reduces these countries’ willingness to cooperate, future negotiations will be very difficult.

Each year that goes by will make it harder to reverse the damage in developing countries

 A more climate-friendly U.S. president could bring climate finance back on track, but the delay in climate action in the interim could be costly. Early investments in clean energy and energy efficiency could put emerging countries on a low-carbon development track. The risk is that these countries could find themselves with lots of expensive energy infrastructure running on fossil fuels. Fixing the damage later would be hard — and even costlier.

For other industrialized countries, the question is whether they can fill the gap in climate finance that U.S. noncooperation leaves. Japan, the European Union and others have the funds, but their willingness to pay for climate protection in uncertain economic times is far from clear. These issues will be prominent soon, as countries plan to review the state of climate finance in 2018.

There has been much talk of China “taking the driving seat” on climate change in the absence of U.S. leadership. But would finance from China restore faith in the trustworthiness of industrialized countries?

If China were to replace the industrialized countries as a climate finance leader, this would be yet another sign that the wealthier countries are not willing to step up and lead on climate. For now, China’s climate leadership remains uncertain, as the country remains dependent on coal despite rapid progress in clean-energy investment — and Beijing hesitates to commit to goals it might fail to achieve.

Trump’s hostility to climate policy poses a threat to future climate cooperation because it threatens to break a promise that industrialized countries made together in the 2015 Paris talks. Other industrialized countries would reap lots of goodwill and long-term benefits from filling the gap, but it remains to be seen whether they are willing and able to put together the funds required.

Johannes Urpelainen is the Prince Sultan bin Abdulaziz Professor of Energy, Resources and Environment at the Johns Hopkins School of Advanced International Studies. He is also the founding director of the Initiative for Sustainable Energy Policy (ISEP).