President Trump will withdraw the United States from the Paris climate accord, which is aimed at sharply cutting the world’s greenhouse gas emissions. If global emissions continue at the so-called business-as-usual level, they could reach 69 gigatons by 2030.

In 2015, nearly 200 countries signed the Paris agreement and set individual targets to reduce emissions. Those pledges would reduce global emissions to 56 gigatons in 2030.

The United States is the world’s second-largest carbon polluter. Its pledge to cut emissions made up a substantial portion of the overall agreement. Other initiatives by states and companies may help reduce American emissions.

China, the world’s largest polluter, said it would remain committed to the agreement “regardless of how other countries’ climate policies change” and encouraged other countries to do the same. China is expected to emerge as the new global leader on climate.

The European Union also remains committed to its pledge. Miguel Arias Cañete, the European commissioner for climate action and energy, has said that the bloc “will defend the clean energy transition.”

Concern has risen over how much India, the third-largest polluter, and other developing countries will be able to do without financial support. India, Brazil, South Africa, and China have asked that developed nations “honor their commitments” to give $100 billion a year. President Trump has said he will cut payments to United Nations climate programs.

The overall goal of the agreement is to limit global warming to less than 2ºC. Most of the current pledges do not go beyond 2030. Longer term pledges, which countries will submit periodically, will need to be stronger to reach the goal.