UN humanitarian organisations operating in Darfur belatedly acknowledged this week that conditions are poised to deteriorate rapidly for some 4.3 million conflict-affected persons in the vast western region of Sudan, which for five years has been the site of genocidal counter-insurgency warfare. A "perfect storm" of threatening developments is brewing, warned UN humanitarian coordinator Mike McDonough on Sunday, and there can be little quarrelling with his grim assessment. Most ominously, the UN's World Food Programme reduced daily food allowances for beneficiaries in Darfur by almost 50% at the beginning of May. Now, the WFP and other UN agencies are warning that "at least 2.7 million people will be affected by a reduction for at least the next two months." These next two months, unfortunately, are in the middle of the rainy season, which largely coincides with the traditional "hunger gap" between spring planting and fall harvest. Malnutrition rates are rising even as heavy rains will soon turn much of Darfur's terrain into a sea of mud and a network of raging torrents, making food deliveries to many locations impossible by ground transport.

What prompted the WFP to cut rations to Darfur's long-suffering civilians? Unsurprisingly, given the region's increasingly violent character, the answer is insecurity, an issue that both UN and nongovernmental humanitarian organisations have repeatedly raised in the most urgent of terms. Food truck convoys, which must make the long trip from Khartoum through Kordofan Province and into Darfur, face the constant threat of hijacking. Drivers are beaten, robbed and too often killed. According to the UN, this year alone there have been 160 vehicle hijackings in Darfur, and eight humanitarian workers have been killed.

As a result, WFP drivers increasingly refuse to make the dangerous trip, and only approximately half the required food tonnage is reaching Darfur. The regime in Khartoum should of course provide military escorts for these critical, though highly vulnerable, convoys. But the National Islamic Front (National Congress party) comprises the very men responsible for orchestrating the Darfur catastrophe. Although they have mouthed various commitments about protecting food convoys, they have in fact done nothing of significance. Militarily, the regime is still responding to the ill-conceived attack on Omdurman, Khartoum's twin city, in early May by the Justice and Equality Movement rebel faction. A proxy war against Chad, which has supported JEM, seems of considerably greater urgency to Khartoum.

But massively reduced food deliveries, while critical, are only part of a deteriorating humanitarian picture in Darfur. The fall harvests in both North and South Darfur (three-quarters of the region's population) were disasters, and there is no evidence that this year will be better, given the terrible insecurity in rural areas. Indeed, the UN notes that 180,000 people were displaced from their homes in the first five months of 2008. And yet camps are already over-crowded, and in many the water tables are falling dangerously low. Both water and sanitation services are overstretched, the UN agencies note, and "diseases such as diarrhoea and acute respiratory infections in the forthcoming rainy season will be more severe if people are weakened by a shortage of food." Khartoum bridles at public use of the word "cholera", but both cholera and dysentery epidemics loom threateningly if people resort to drinking ground water.

Yet another problem is simply ignorance. Khartoum has compelled the UN organisations to suppress their own malnutrition studies, as well as those of nongovernmental organisations, thus making the most efficient targeting of resources impossible. Last fall, the last time nutrition studies were widely promulgated, malnutrition among children under five was above emergency thresholds. The UN now asserts that malnutrition is in line with what was observed last year at this time, but so much of Darfur is inaccessible (approximately 60% at any given time) that it is hard to know how to quantify the "spikes" in malnutrition reported. And the very fact that Khartoum has suppressed 11 studies, and has worked to limit the ability of humanitarians to gather new data bearing on malnutrition, reveals all too much of the regime's attitude toward the people of Darfur and humanitarian efforts generally.

Shamefully, the UN organisations have been reduced to pleading, declaring that the monitoring of malnutrition and sanitation "can only succeed if aid agencies are able to undertake and release the results of surveys and assessments in a timely manner and without restrictions." Without any tool or leverage to secure compliance, these organisations can merely state that "the government of Sudan must urgently enact its agreement to release the results of technically cleared humanitarian surveys - including nutritional and crop surveys." But unless a four-year pattern of humanitarian obstruction is addressed meaningfully by the UN security council, pleading is all that will be left to aid workers.

Conscious of the impending rainy season, the UN organisations speak for the broader "humanitarian community in Sudan," which is "warning that limited time remains to safeguard against an increasingly precarious situation." But time is decidedly not on the side of the humanitarians. Recent regional weather forecasts predict that heavy seasonal rains will soon reach Nyala (pdf), the capital of South Darfur and a humanitarian hub. Much of the area affected by the rains, which gradually move northwards, peaking in August and September, will soon be impassable. The pre-positioning of food that has taken place in the past as a response to transport challenges during the rainy season is woefully inadequate this year.

How to improve humanitarian access? How to protect WFP convoys? How to provide the minimum security that will allow aid workers to continue? How to police the camps for displaced persons, which have become tinder-boxes of rage, despair, and too often ethnic tensions? Some argue that because there is no peace to keep, it makes no sense to have sent a UN peace support operation to Darfur. And to be sure, the UN/African Union "hybrid" mission for Darfur (Unamid), authorised by the UN security council last July, has proved barely distinguishable from its weak and ineffectual African Union predecessor. The shift to a UN command at the beginning of this year has been followed by deployment of only a few hundred additional personnel for a mission that was to have included more than 6,000 civilian police and more than 19,000 troops, all meeting UN standards for training and equipment. Altogether, only about 9,000 troops and police have actually deployed, and Darfuris are fast losing any confidence they may have had that this UN force would make a difference.

Let us be very clear, however, about the consequences of refusing to muster the international will and courage to make of the UN-authorised mission a success: humanitarians will leave, food distribution will come to a halt and massive starvation and disease-related deaths will occur in the near term.

Glib declarations that there is "no peace to keep" in Darfur skirt the true questions: Are we really prepared to see the world's largest humanitarian effort collapse amid insecurity? Are we really prepared to accept the consequences of a precipitous end to international aid operations in Darfur? Are we really prepared to countenance the agonising deaths of hundreds of thousands of innocent civilians? There are no more urgent questions in the world today.