If fine words could save lives, the survivors of Cyclone Nargis would have nothing to fear. Germany's Angela Merkel found the Burmese junta's indifference to people's plight "inexplicable", only to be trumped by French President Nicolas Sarkozy's "utterly reprehensible". For once, US President George Bush seemed to have come up with a few bons mots with his description of the Burmese regime as "either isolated or callous" but the award for soundbite of the week surely goes to British Foreign Secretary David Miliband's "malign neglect" and "a humanitarian catastrophe of genuinely epic proportions". Well done, David.

However, the most revealing comment came from a clearly frustrated Foreign Office minister, Lord Malloch-Brown, in Rangoon yesterday. "We cannot accept no' for an answer," he said of the generals' refusal to admit foreign aid workers. What's interesting is that it appears to be diplomatic-speak for exactly the opposite.

As things stand, there is nothing in prospect to mitigate what is becoming a triple calamity. First, the cyclone itself. Even with more early warning from the government, many would have died as hurricane winds tore through handmade homes, followed by a 12ft tidal wave. The tally of dead, officially 35,000, will probably end at nearer 100,000. Those "lucky" enough to survive now face a macabre obstacle course.

At this moment a second entirely man-made tragedy is unfolding as thousands more succumb to the effects of disease, exposure and "cyclone burns", caused when grit whipped up by the storm rips off skin. With little or no fresh water and water courses choked with faeces and bodies, diseases such as cholera, dysentery and diarrhoea are killing children, the elderly and the weak. More will succumb to malaria and dengue fever as mosquitoes breed freely in the many pools of stagnant floodwater.

Now Elizabeth Byers, of the UN Office for the Co-ordination of Humanitarian Affairs, warns of a third impending disaster: starvation. By yesterday, the World Food Programme had been able to distribute only 175 tonnes of food.

Yet, while rice stocks in Burma near exhaustion, unbelievably rice exports continue. While most governments consider themselves to have a duty of care for their people, this one seems to have a death wish for its.

Yesterday some of the few aid workers to have penetrated the Irrawaddy delta reported that, while foreign food aid was piling up on the runway at Rangoon airport, an hour's flight away soldiers were distributing small quantities of low-grade rice. Some of it was rotting. Who in their right mind could claim, as Vice-Admiral Soe Thein did this week, that Burma has no need of foreign aid workers or logistical experts? Yesterday, as soldiers continued to unload planes by hand, what was probably the final diplomatic initiative was exhausted when the Burmese government sent packing a Thai delegation with fleas in their ears. The most charitable interpretation is that this isolated and xenophobic regime is concerned about loss of face. A more likely one is that it knows opening the country to outsiders would lead to its downfall.

Government troops, who were swarming everywhere during last September's pro-democracy demonstrations, were nowhere to be seen in most of the affected region, though seem to manage to pop up to arrest and deport any foreign journalist who manages to get across the border. Meanwhile, there are stories of human traffickers prowling devastated villages on the look-out for young women to trade as prostitutes. Traders in human organs are probably not far behind. Could Dante have devised a more grotesque dystopia?

In China, too, the stench of death is everywhere, after this week's Sichuan earthquake, but the scale, efficiency and tone of the government's response merely lends emphasis to the genocidal inadequacy of the Burmese junta.

While aid trickles along the roads between Rangoon and the Irrawaddy delta, in China the highways are packed with aid trucks, soldiers and heavy equipment. There are going to be terrible recriminations about cost-cutting in Chinese schools built of concrete without metal reinforcement, but it's hard to fault the legions of red-eyed soldiers with spades and rain capes, digging around the clock for survivors. The few images emerging from Burma show desperate children begging for food or listless survivors squatting beside flattened homes, while China has managed to convey the image of a well-oiled machine bringing some order to the chaos. And, by contrast with past disasters, the Chinese government is trying to show it cares. While Prime Minister Wen Jiabao rushed to the afflicted area, declaring: "Your pain is my pain" to the bereaved, Burma's General Than Shwe has been in hiding. It's hard to know whether this is China minding its Ps and Qs in an Olympic year or a burgeoning affluent middle class that expects more from its government than in the bad old days when disaster casualty figures were state secrets.

There's another interesting contrast between the anodyne global response to Burma - full of sound and fury, signifying next to nothing - and the surge of empathy and generosity that followed the Boxing Day tsunami in 2004, which triggered the biggest international aid effort in history. Perhaps it was the sprinkling of western tourists, mixed in with the barefoot farmers and fishermen of Indonesia and Sri Lanka that made the difference.

Yet, if we continue to stand by, waiting for an invitation from the Burmese government that will never come, the eventual toll from a triple catastrophe of cyclone, disease and starvation in the Irrawaddy delta could easily exceed lives claimed by the tsunami. Oxfam believes 1.5 million are at risk.

If the UN can't muster a multilateral response before it's too late, it raises questions about why it exists. It raises questions about what is known as "R2P", the UN's "responsibility to protect", a doctrine championed by Canadians and recognised by the UN in 2005. The role model was Nato's military intervention in Kosovo.

This week Ed Luck, special adviser to the UN secretary-general, advised that R2P only applied to genocide, war crimes, crimes against humanity and ethnic cleansing, but not negligence following a natural disaster. Why not? In this country, if someone threatens the life of a child or even a dog by locking it in a room and walking away, the authorities, rightly, consider it their duty to break in and rescue them. Unless we are as morally bankrupt as the Burmese generals, we should do the same there, if not under R2P, then under the 2006 Security Council ruling imposing a responsibility on the international community to protect people whose governments fail to do so.

This specifically includes "the denial of humanitarian assistance".

The west seems more than happy to breach national sovereignty when oil or opium or militant Islam are involved. Why can international law be used to validate bombing into submission the people of Iraq and Afghanistan but not to save the lives of 1,500,000 poor people, traumatised and abandoned by their own government. It's not good enough for western governments to say the right thing. They must do the right thing.