At the height of the last economic boom most rich countries declined to redistribute wealth at even the minimum levels needed to improve, or just stabilise, the basic health structures of the developing world. Shamefully, they refused the trade deals necessary to let the poorer countries kick-start their own economies, and thereby strengthen their social infrastructure.

They doled out the crumbs from their table, like aristocrats before the French Revolution, never countenancing the peasants becoming traders, merchants (and competitors) in their own right.

Some countries - Sweden, Norway, the Netherlands, France and Britain - did better, recognising the imperative to support lifting millions out of destitution and despair. But Australia was not one. Rather, it is a deadbeat of international aid.

We allocate about $3 billion a year on overseas development assistance, or just over 0.3 per cent of gross national product, well below the 0.46 per cent average spent by all OECD countries, itself far short of the United Nations target, 0.7 per cent. The Rudd Government has modestly increased it from the derisory levels of the late Howard years, although it is still below the 0.47 per cent spent in first year of the Hawke government.

But even though some countries do better, the OECD estimated the total global amount of development assistance was about $US120 billion ($168 billion) last year. Compare that to world military spending in 2007 of about $US1.47 trillion.

The consequences of these selfish and counterproductive policies are becoming apparent.

In a globalising world, people are free to travel around the world almost as freely as capital. But when people move in large numbers, so do viruses and pathogens of all kinds.

In the past few decades there have been ominous warning signs that the rich world's failure to invest in the poor world's health systems might have serious global consequences. SARS, avian flu, swine flu and HIV/AIDS emerged, initially undetected and unreported, from the poorer countries where primary health-care systems were weak or non-existent. By the time the problem was understood, the damage was done. The pathogens spread around the world as fast as planes could fly.

The present outbreak of swine flu in Mexico is another tolling bell.

If the situation worsens, restrictions will be placed on travel to and from the United States, as happened in Asia at the time of SARS. Apart from the human toll of death and suffering, the airline industry could not survive a prolonged collapse in passenger numbers. This would have dire economic consequences, particularly for sectors dependent on mass travel and commerce.

The enemies that now pose an existential threat to our global civilisation are not "terrorists", "jihadists", teenage pirates or the few pathetic refugees fleeing the carnage visited upon their countries by the industrialised West. Rather they are slivers of virus, and molecules of carbon dioxide.

The vast conurbations of the developing world are largely unsewered. They have little clean water. They pile humans, pigs, chickens, dogs, cats and rats on top of each other. The largest cities each contain as many people as Australia. They are perfect incubators of species-hopping viruses of all kinds. And the viruses only have to make it to the nearest airport to make a global impact.

There is, however, no need to terrify ourselves about the inevitability of new pandemics.

We know how to prevent the spread of most pandemic diseases and to stop minor outbreaks from becoming major problems. A century ago, industrialised countries invested in sewers and water works and created basic primary healthcare systems available to all, regardless of income. Livestock was banished from the cities and instead raised and slaughtered in separate, hygienic new facilities.

It is in our own interest to give to our neighbours the power and resources to eradicate or mitigate these problems. We need to help them embark on massive sewering and water engineering programs, build robust primary healthcare systems and remove large-scale animal husbandry from the cities.

This may take decades, and cost trillions of dollars. But the investment will be dwarfed by the costs of a serious global influenza pandemic. A 2006 Lowy Institute paper by Warwick McKibbin and Alexandra Sidorenko estimated that a mild influenza pandemic would cost the world 1.4 million lives and close to 0.8 per cent of global gross domestic product (about $US330 billion in 2006 dollars). In an "ultra" flu pandemic, 142 million people would die and global GDP suffer a loss of $US4.4 trillion.

The costs of inaction about global heating are similarly staggering.

If we do not invest now in the public health and engineering required to make the cities of the developing world safe to live in, new pandemic diseases and global heating will bring about upheavals, suffering and the displacement of populations that will dwarf even the bloodiest wars of the 20th century.

Australia is contemplating spending vast sums on new armaments and engines of destruction to fight wars of a scope, scale and type unlikely to happen. We will lift our military spending to more than 3 per cent of GDP or about 10 times what we give to development assistance. But no Joint Strike Fighter can target an influenza virus, and no submarine can take out a molecule of carbon dioxide. As is sadly apparent in Afghanistan, armies cannot build or reconstruct nations or provide health care.

We all would be much better off if we immediately reversed the balance between military spending and development assistance. The billions should be spent where they will make a direct and rapid improvement in the human condition, not where they won't.

Bill Bowtell is director of the HIV/AIDS Project at the Lowy Institute for International Policy.