Adapting to global warming could cost up to five times higher than initially estimated -- as much as $500 billion a year by 2050 -- according to a new report out of the United Nation's climate change conference in Lima.

The "Adaption Gap Report," conducted by the U.N. Environment Programme (UNEP), found that even with current publicly sourced funding reaching $23 billion to $26 billion in 2012-2013, "there will be a significant funding gap after 2020 unless new and additional finance for adaptation is made available."

Helping developing countries adapt to climate change "could climb as high as $150 billion by 2025/2030 and $250-500 billion per year by 2050," the report said.

These figures were calculated under the assumption that greenhouse gas emissions could be restricted enough to prevent temperatures from rising to 2 degrees Celsius, a level which, if exceeded, could cause catastrophic planetary effects.

If temperature rise cannot be adequately contained, UNEP said adaptation costs could reach "double the worst-case figures."

The report, produced in collaboration with 19 leading institutes and research centers, expands on previous estimates made by the Intergovernmental Panel on Climate Change's Fifth Assessment Report, which estimated adaptation costing $70 billion to $100 billion by 2050. Those numbers were based on World Bank figures from 2010.

"National authorities and the international community should take the necessary steps to ensure the funding, technology and knowledge gaps are addressed in future planning and budgeting," said Achim Steiner, Executive Director of UNEP and Under-Secretary-General of the United Nations. "Of particular concern are the implications on least developed countries, whose financial resources for investing in development will need to be redeployed to financing adaptation measures."

In November, President Barack Obama announced that the U.S. will give $3 billion to a new international climate designed to help the world's poorest countries address climate change, according to The New York Times.

U.S. Secretary of State John Kerry recently told reporters in Brussels, "We intend to continue to try to build momentum moving into next year."

"We believe that not only is there obviously the practical advantage of responding to the events - to the transformation taking place in the climate that is contributing to very severe weather events, to major flooding, major fires, major drought, to shifts in agriculture and other impacts that have huge cost - but we believe it is becoming more and more evident that it is cheaper to invest in the new technologies and move to the clean energy economy," Kerry said. "And we are going to continue to work for that."

A separate report released from the climate conference named Australia as the worst-performing industrial country in terms of climate change, as it has apparently "reversed the climate policies previously in effect."

China, the world's largest emitter, was ranked 45th, while the U.S. was placed at 44th, The Guardian reported.