Even in the best-case scenario, summer months without sea ice will start to occur in the Arctic sometime in the middle of the century, earlier than top climate scientists had anticipated. In its most recent historic assessment, the United Nations-sponsored Intergovernmental Panel on Climate Change predicted that if greenhouse gas emissions from humans remain high or moderate, the region would start to experience Septembers without sea ice around 2050. The current study, which was released in Nature Communications, asserts that this will nonetheless occur even in a low-emissions future. By 2030 to 2040, higher emissions will lead to Septembers without ice. "We basically are saying that it has become too late to save the Arctic summer sea ice," said Dirk Notz, an oceanographer at the University of Hamburg in Germany who specialises in sea ice and is one of the authors of the study, as well as an IPCC report author. "There's nothing really we can do about this complete loss anymore, because we've been waiting for too long." While the IPCC speculated that an ice-free summer would likely take place for the first time before 2050, the models it looked at allowed for some hope that a low-emissions path could postpone such a grim milestone, Notz said.