International efforts to mitigate climate change are insufficient to meet the goal of keeping global warming to below 2 degrees Celsius above pre-industrial levels, a United Nations report warned Monday, just a month before a major conference on the issue is held in Durban, South Africa.

The report laid out a list of options to achieve the target, including more cuts in greenhouse gases from additional sectors, stronger accounting rules both within the UN Framework Convention on Climate Change (UNFCCC) and through other multilateral and domestic strategies, sharing mitigation efforts based on countries' capacities or contributions to the problem, and legally binding commitments.

The report, Building the Climate Change Regime: Survey and Analysis of Approaches, was published by the UN Environment Programme (UNEP) and the World Resources Institute (WRI), a global environmental think tank with the support of the Irish Government. It reviewed more than 130 proposals put forward by governments, non-governmental organizations (NGOs), and academics to design a climate regime capable of delivering adequate mitigation.

It is the latest in a long series of UN warnings that world is falling behind in the battle against global warming. Just last month, at a Leaders' Dialogue on Climate Change on the eve of the high-level session of the General Assembly, Secretary-General Ban Ki-moon urged governments to show greater commitment.

Scientists say that keeping to the 2-degrees Celsius limit over the course of the 21st century is crucial to avert widespread disasters, from the disappearances of low-lying island nations under rising seas and searing droughts, famines, extreme storms and flooding, to the extinction of species.

"The analysis provided in this new report offers many options that can happen either in the formal negotiations or as complementary measures elsewhere, options that can assist the more than 190 United Nations Member States move quickly to harvest the opportunities of a transition to a climate resilient, low-carbon, resource-efficient Green Economy," UNEP Executive Director Achim Steiner said.

The report highlights the need to mobilize a range of public and private sector groups at the international, national and sub-national levels, who can contribute to climate governance, emission reductions and adaptation investment.

"At the upcoming climate meeting in Durban, countries have the opportunity to turn these ideas into action and start to bridge the ambition gap needed to truly have an impact," WRI Interim President Manish Bapna said, while Irish Environment Minister Phil Hogan called the report very timely.

The report stressed that the issue of legally binding commitments is central to debates ahead of Durban and noted that it is possible to build upon existing UNFCCC processes to strengthen the climate regime and raise the overall level of ambition to reach the target.

"Whilst a number of studies have demonstrated that the level of climate mitigation pledged to date is insufficient to limit temperature increases to 2 degrees Celsius, this paper clearly demonstrates that there are a range of good ideas and options available that could help correct the course and move toward a safer and more stable climate," UNEP said in a news release.