Lazaro Sumbeiwyo and John Danforth

The world’s attention was rightly seized by the terrible conflict in Sudan’s western region of Darfur, in which hundreds of thousands of civilian lives were lost. It is often forgotten, however, that the tragedy of Darfur came after Sudan’s north-south conflict, Africa’s longest running civil war, in which more than 2m people were killed. On Friday it is five years since the historic Comprehensive Peace Agreement was signed between north and south Sudan, yet there is a real threat of all-out war returning to Sudan and still no permanent resolution to the Darfur conflict.

We are writing as individuals privileged to experience the peace process at close hand. We witnessed the long, frustrating and sometimes seemingly impossible process of negotiating the CPA. We saw how the parties’ common desire for peace gradually overcame enmity and distrust, and how the CPA, signed on January 9 2005, established a government of national unity between two former enemies.

The CPA spelled out how the government of national unity would deal with delicate issues such as wealth- and power-sharing, border demarcation and repositioning of troops over a six-year transitional period. It also established a semi-autonomous government in the south and three transitional areas. In two of those areas, Southern Kordofan and Blue Nile, residents were promised a democratic process of popular consultations; in Abyei, the third area, they secured the right to decide, through a referendum, whether to join Southern Kordofan (part of north Sudan) or the southern Sudanese state of Bahr El Ghazal. Central to the CPA was an affirmation of the right of southern Sudanese to hold a referendum on self-determination in 2011.

Since then, five years have lapsed and the parties stand on the brink of a new chapter in Sudan’s history. National elections are scheduled for April but crucial parts of the CPA have not been implemented. Unless international support is dramatically increased to help north and south agree on the foundations of their future, the elections and referendum may throw Sudan back into civil war.

Deteriorating conditions in Sudan highlight the urgency of the situation. Violence in south Sudan spiked in 2009 – in recent months more people have been killed there from armed conflict than in Darfur. At the same time, while violence has decreased in Darfur, the root causes of conflict have not been addressed; and the situation in eastern Sudan and the transitional areas of Abyei, Southern Kordofan and Blue Nile is also still volatile.

The CPA was not able to solve every problem. But it was designed to pave the way for elections and a southern referendum intended to be the culmination of a six-year process to help Sudan emerge more democratic, better governed and at peace. Time is running out to realise these aspirations. Sudan is three months away from elections that are likely to fail to live up to democratic standards and to exacerbate ongoing violence.

We are deeply concerned that the historic opportunity offered by the CPA – and hailed by world leaders as a momentous victory for peace – will be forgone unless the intensity of effort required to reach the agreement in the first place is resuscitated. We implore concerned nations to support the Sudanese parties in an attempt to find a permanent peace. Here are three ways countries can help.

First, agree on a joint mechanism, including intensified mediation and technical support, to help north and south Sudan implement the remainder of the CPA, including the popular consultations in Southern Kordofan and Blue Nile as well as the Abyei and southern referendums.

Second, press the government of national unity to make free and fair elections possible.

Third, support increased measures for civilian protection by the UN Mission in the Sudan and the United Nations-African Union peacekeeping force in Darfur, including through contingency planning around potential flashpoints for violence.

It is already too late to implement the full promise of the CPA. But there is still some time to avoid a near certain disaster that would set the people of Sudan back to the darkest days of the north-south war. We urge world leaders to use every day that is left.

Retired Lt Gen Lazaro Sumbeiwyo was chief mediator in the Sudan peace talks. John Danforth was US special envoy in Sudan, 2001-2004, and is on the board of Refugees International