There were high hopes that last year's United Nations (UN) Climate talks in Copenhagen-COP15, would deliver a legally binding agreement for action on climate change.
But the outcome, "the Copenhagen Accord" was instead a political 'statement of intent' that fell significantly short of expectations.
Now, after a year of interim meetings and several texts, parties to the UN Framework Convention on Climate Change (UNFCCC) would gather in Cancun, Mexico dubbed "COP16", from November 29, with the sole aim to try again.
Their success would largely depend on settling disputes, particularly between the developed and developing world.
About six key issues are expected to come up for discussion, namely shared vision; adaptation; climate finance; technology transfer; reducing emissions from deforestation and degradation (REDD+) and post-2012 emissions reduction targets.
Background: In the Bali Action Plan, adopted at the 2007 UNFCCC talks in Indonesia, countries agreed to develop a shared vision of the long-term cooperative action needed to implement the convention effectively up to and beyond 2012, when the first commitment period of the Kyoto Protocol ends.
The vision is meant to include a long-term global goal for emission reductions that takes into account the principle of 'common but differentiated responsibilities' whereby everyone shares the common goal of effectively dealing with climate change, but with differing degrees of responsibilities for causing it as well as the different socioeconomic conditions and technological and financial capacity for action that exists within each country.
This long-term goal addresses mitigation for all parties to the convention, including the United States and large emerging emitters such as China and India that do not have binding commitments under the Kyoto Protocol.
Maintaining separate discussions on a long-term goal has been very important for the large emitting developing countries that are looking for voluntary commitments and are resisting the risk of being roped into binding post-2012 emissions reduction targets.
The Copenhagen Accord, similarly, emphasises the need for funding, and includes a 'collective' promise of US$10 billion each year until 2012, rising to US$100 billion by 2020.
But a large gap remains between the level of funding made available and estimates of that which is needed.
Progress in negotiating a deal on climate finance has been slow the biggest obstacle is raising new and additional money through public funding sources of developed countries.
Another bone of contention are the 'allocation decisions' that determine who gets what and gives priority to adaptation and low carbon development efforts in developing countries.
It is controversial because, according to the commitments made under the UNFCCC, developed countries are committed to provide financial assistance to all the developing countries.
The extent to which developing countries would effectively implement their commitments under the convention depended on the effective implementation by developed countries of their commitments under the convention, in particular related to financial resources.
But developed countries have so far failed to provide sufficient financial assistance to meet the adaptation and mitigation needs of developing countries.
Instead, they wanted developing countries to commit to binding agreements and to prioritise countries among them for assistance Environment Climate Negotiations 3 Hohoe Compromise would be required on both sides to find middle ground on this issue.
Animosity between the two sides, particularly between superpower rivals China and the United States, rose to dizzying heights at the pre-Cancun discussions in Tianjin, China in October 2010.
China blamed the United States for failing to meet its responsibilities to cut emissions, while Washington accused Beijing of refusing to have its voluntary energy savings verified internationally and criticised its insistence on legally binding commitments for developed countries and purely voluntary ones for the emerging ones.
The lead Chinese climate negotiator, Su Wei, described the United States of behaving like a 'preening pig', complaining about Beijing when Washington had done so little itself.
The lead US negotiator, Jonathan Pershing, responded that Washington would not sign any binding deal that did not also bind China.
Other unresolved issues in the negotiations on climate finance include: who will oversee the implementation of climate funds (the governance issues); how financial resources would be accounted for; how 'new and additional' funds would be defined and what would qualify as a clear and transparent baseline from which to count new funding.
Tricky Targets: Perhaps the most contentious issue in global climate talks is emissions reduction targets beyond 2012.
The need to reduce emissions is clear, if we failed, global temperatures will continue to rise, exacerbating the impacts of climate change.
Under the UNFCCC, a special group, the Ad hoc Working Group on Further Commitments for Annex 1 Parties under the Kyoto Protocol (AWG-KP), has been trying to establish post-2012 emissions reduction targets since 2006.
But despite more than four years of work, it has made little progress.
For many developing countries, a second commitment period of the Kyoto Protocol (that is, emissions reduction targets post-2012) is a prerequisite for any global climate deal.
The G77 and China, for example, have said that they would not compromise on a second commitment period.
But one of the biggest problems facing the working group is that countries cannot agree on how to set the targets for this period.
Developed countries, hard hit by the economic crisis, want a bottom-up approach where they could set targets that suit their national situation and aggregate them into a global goal.
But many developing countries are concerned that this approach was not stringent enough, when individual targets are aggregated, they fall far short of what science says was required to avoid increasing global temperatures above the 'tipping point' of 2ï¿½C.
So the developing world is pushing for a top-down approach that sets a global target, rooted in science, and then distributes contributions to that target based on an agreed methodology.
With neither side looking likely to give much ground, negotiations in Cancun may prove difficult.
Divisive Tales of the Table to be Negotiated in Cancun: Whereas developing nations would want all building blocks in the Bali Action Plan included in negotiations, developed nations crave for a focus on long-term global goal for emissions reduction.
On the issue of adaptation, developing countries are demanding negotiation for financial compensation for the unavoidable loss and damage caused by climate change, developed counterparts are calling for further study.
About climate finance, while developing nations demand new and additional money through public funding sources, developed nations want more binding action from developing counterparts.
Whereas developing countries wanted easy and affordable access to patented technology on technology transfer, developing nations want stronger patent laws to protect intellectual property rights.
Beyond Cancun: Resolving each of the issues outlined above would be critical to establishing a global climate deal that parties to the UNFCCC are happy to sign.
But the breadth and depth of disputes makes it highly unlikely that a binding agreement will be reached in Cancun.
The disappointing result in Copenhagen has led to a widespread loss of faith in global climate change negotiations.
The UNFCCC has spent much of the past year simply assessing the status of its negotiations, agreeing ways of working and looking for ways to rebuild trust in the process.
Hopes are much lower this time round; both the UNFCCC Executive Secretary and the UN Secretary General have admitted to reduced expectations of a substantial outcome.
And across the board, people are already looking beyond Cancun, perhaps to next year's talks in South Africa, as the likeliest place for a long-term global climate change agreement to be reached.
By Maxwell Awumah.