The head of the United Nations’ top science panel on climate change said Tuesday that the world needs to “do more and faster” to prevent global warming on a scale that would cause irreversible environmental damage and hit poor societies hard.

Hoesung Lee, who chairs the Intergovernmental Panel on Climate Change (IPCC), told diplomats at the U.N. climate summit in Poland that scientists had reviewed data for their recent report on the impact of average global temperature increases.

“The report shows that not just action, but urgent action is needed,” Lee said. His comments come as national leaders and ministers gathered in Poland for the final stretch of the two-week talks, with just days left to break through issues that diplomats have struggled to resolve.

U.N. climate chief Patricia Espinosa urged delegates to show a “spirit of unity” through the end of the week.

Lack of unity was on full display Saturday, when the United States, Russia, Saudi Arabia and Kuwait blocked endorsement of the IPCC’s report. The move prompted anger from environmental groups, which accused the four countries of putting their interests as oil exporters before the need to curb global warming.

Scientists say emissions of greenhouses gases such as carbon dioxide — which is produced through the burning of fossil fuels — need to drop significantly by 2030. Emissions need to reach near zero by the middle of the century if the 2015 Paris accord’s most ambitious goal is to be achieved.

“We are moving in the right direction in many areas, but we need to do more and faster,” said Lee, adding that cutting emissions sooner would give the world more room for moving later.

Negotiators have until Friday to finalize the rules of the Paris accord, including details such as how countries will record and report their emissions.

The talks are also meant to push countries to commit to more ambitious targets for reduction in greenhouse gas emission.

Poor countries, meanwhile, want promises of financial support to tackle climate change.

— Associated Press