Over the past two weeks, international negotiators from 195 member nations met in Warsaw, Poland, for the 19th Conference of the Parties (COP 19) to the United Nations Framework Convention on Climate Change (UNFCCC). The goal of the meeting was to work towards developing a new legally binding international treaty to curb rising global greenhouse gas (GHG) emissions in order to limit the global average temperature increase to 2°C by the end of the century. This future agreement, slated to be signed in 2015 and enter into force in 2020, would replace the Kyoto Protocol, which expires in 2020. The conference came after the release earlier this autumn of the 5th assessment report from the Intergovernmental Panel on Climate Change, which again states that warming of the climate system is unequivocal and asserts that "human influence on the climate system is clear". What was hoped for at the end of COP 19 was a clear roadmap and timeline to conclude negotiations on a new international climate treaty by the COP meeting in Paris at the end of 2015. Negotiations ended on Saturday with a directive for all nations to establish and submit their emissions reduction contributions to the UNFCCC by early 2015, providing a short window of time for review before the Paris conference. A stalemate over the use of the word 'commitments' ran the conference into the weekend, but the consensus for nations to submit 'contributions' rather than 'commitments' roughly keeps the negotiations on track for the 2015 agreement deadline. In the interim, governments will draft the new climate agreement, which will appear at the next UN climate conference in Peru in 2014. Despite this progress, the question currently remains as to whether each government's contributions to reduce GHG emissions will be enough to keep increased average temperatures to 2°C by 2100. According to the UNFCCC website: "The reality is that a looming gap remains between current national and international actions and intentions to reduce emissions and the actual level required to keep average global temperatures rising no more than two degrees above their pre-industrial level." The origins of UN climate negotiations The UNFCCC is an international environmental treaty that was originally negotiated at the UN Conference on Environment and Development in 1992. The treaty's objective is to "stabilise greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system" (UNFCCC is also the name of the secretariat that supports the institutions involved in international climate change negotiations). Since the treaty was established, the 195 parties to the convention have met annually since 1995. The first UNFCCC international climate treaty, the Kyoto Protocol, was adopted in 1997. The Kyoto Protocol established legally binding obligations on 37 developed countries to reduce greenhouse gas emissions with emission reduction targets. The Kyoto Protocol entered into force in 2005 with 192 parties. The Protocol's first commitment period started in 2008 and ended in at the end of 2012. In 2011 and 2012, a weaker version of the Protocol was agreed upon and extended for a second commitment period, which began on 1 January 2013 and will end in 2020. At the 2007 COP in Bali, it was decided that a framework for climate change mitigation beyond 2012 was to be agreed upon at the 2009 COP in Copenhagen. However, no legally binding international agreement was adopted at the Copenhagen conference. The document that was ultimately produced, the Copenhagen Accord, addressed climate change as one of the greatest modern challenges, asserted that actions should be taken to keep the average temperature increase to below 2°C, but did not include any legally binding commitments, nor a target year for peaking emissions, nor a baseline for the 2°C target. In 2011, the Durban COP laid the framework for the time period beyond 2020, when the Kyoto Protocol expires. At the Durban conference, all member nations committed to a "comprehensive plan that would come closer over time to delivering the ultimate objective of the Climate Change Convention: to stabilise greenhouse gas concentrations in the atmosphere at a level that will prevent dangerous interference with the climate system and at the same time will preserve the right to sustainable development". The parties also launched a new platform of negotiations to deliver a "new and universal greenhouse gas reduction protocol, legal instrument or other outcome with legal force by 2015 for the period beyond 2020. The new negotiation critically includes finding ways to further raise the existing level of national and international action and stated ambition to bring greenhouse gas emissions down". Since the Durban conference, the UNFCCC has been working towards this goal and the development of a second treaty. Obstacles to be overcome for coordinated universal action on climate change To limit GHG emissions and thereby keep the global temperature increase below 2°C, coordinated international action is required, resulting from an effective, legally binding universal agreement, which has as of yet not been achieved in international climate negotiations. Any future agreement must include not only numerical emission reduction targets and timetables, but also a strong enforcement mechanism (the Kyoto protocol only had the latter, and only addressed industrialised nations). Finally, an effective future agreement needs to have a mechanism for rich countries to effectively transfer technology and resources to poor countries to finance sustainable development. While mechanisms for technology transfer and resources have been discussed and were negotiated at the Warsaw conference, along with a mechanism for reducing deforestation (a potent source of GHG emissions), a legally binding international agreement for emissions reductions will likely remain elusive. Burden sharing is difficult to achieve, and the free rider problem, inherent to climate reduction efforts being a public good, gives each nation an incentive to understate their true willingness to engage in climate mitigation action in the hope that other nations will shoulder more of the burden. Public goods problems are not new, though they have often proven difficult to overcome. Despite the less than optimistic conclusion of the Warsaw conference, climate change mitigation needs to be effectively addressed. Even if we are successful in holding global warming to 2°C, we will still have a climate that is fundamentally distinct from the one that human civilisation has known over the last 10,000 years. If GHG emissions are not limited, CO2 levels will climb well above double their pre-industrial levels to 800 or 900 parts per million by 2100, leading to a likely temperature increase of 5°C, with mostly negative consequences for human well-being and the survival of many species on earth. *Libby Blanchard  is doing a PhD in Geography. Picture credit: Stoonn and www.freedigitalphotos.net.