Two weeks of climate talks organized by the United Nations ended Thursday as countries failed to resolve differences about implementing the Paris climate accord.
The negotiations will resume in Bangkok in September, where an extra week's meeting has now been scheduled.
The pact's 197 signatories have set a December deadline to agree on the precise rules that countries have to stick to under the Paris agreement.
The lack of progress threatens to unravel three years' worth of work to complete the Paris agreement, a landmark deal reached in 2015 that set a goal to limit fossil-fuel pollution in all nations for the first time and keep global warming below 2 degrees Celsius by the end of the century.
Overall progress at the meeting in Bonn was very slow, with some countries such as China looking to renegotiate aspects of the Paris deal.
Patricia Espinosa, head of the U.N. agency that oversees climate talks, described the package being negotiated as "highly technical and complex.'' It aims to ensure that the efforts countries claim they're making in the fight against global warming can be verified and compared.
The administration of President Barack Obama was widely credited with helping to bring together the diverging interests of rich and poor countries in the drive to secure the Paris deal. His successor, President Donald Trump, withdrew the U.S. from the accord in June 2017. His administration has attacked climate science, saying it questions whether human activity is behind climate change, and is focused on boosting the fossil fuel industry.