The warning signs are there for the perfect storm
The unusually large rainfall from this year's monsoon has caused the most catastrophic flooding in Pakistan for 80 years.
Perhaps 20m people are homeless, along a path of destruction over 600 miles long. Meanwhile, the UN is warning of impending food shortages and the World Bank is estimating that £640m-worth of crops have been ruined.
This is a crisis of the very first order. What is particularly disturbing about it is that, in spite of long-range forecasts, appropriate warnings appear not to have been issued.
Heavy monsoon precipitation has increased in frequency in Pakistan and western India in recent years. Last year, deadly flash floods hit north-western Pakistan. Karachi was also flooded.
The danger is that Pakistan, and the Indian subcontinent in general, will become the focus of much more regular catastrophic flooding. This is not just a question of trying to mitigate natural hazards better, but one with profound implications for geopolitics and inter-national security.
How can better flood warnings and prevention measures be a part of the solution? On the warnings point, there have been major advancements since the 1990s in the international exchange of weather forecast data, with regional computer models used widely by authorities across Asia.
In practice, however, there is great sensitivity in many countries about long-term warnings being issued publicly, especially in international media, due to the anxiety and potential mayhem this could cause.
Especially once heavy rain is imminent, much better short-term warnings could help to inform local communities about the likely duration of precipitation and flooding; such warnings are now much more reliable because the interaction between flood waters, soil and vegetation is better understood.
Yet whereas some countries, for instance China, have generally issued effective short-term warnings, few — if any — were apparently given by the Pakistani authorities in advance of this most recent disaster.
The Chinese example is a good one for other countries in the region to aspire towards. Local communities in China receive detailed short-term forecasts before floods — allowing sufficient time for community workers to move people, especially the elderly and sick, to higher ground. Similar arrangements have also been established in Bangladesh.
The need for such short-term warnings is especially clear in developing countries. If monsoon flooding does become a perennial concern in Pakistan in the future, what may be inevitable is migration away from particularly flood-prone areas towards urban zones. Similar movement to urban areas has taken place in Africa.
As for prevention, some argue that nothing could have been done to mitigate the flooding. Aside from the very real issue of authorities being weighed down by security and other social problems, one of the key issues here appears to be the embezzlement and mis-spending of public funds for flood prevention.
Syed Adil Gilani, head of Transparency International's Pakistan office, says that 60%-70% of the 85bn Pakistan rupees (about £640m) spent by the country's Federal Flood Commission has been embezzled since the commission's inception back in 1977. Whatever the truth of this claim, the Pakistani government, the military, and the international community will now need to consider carefully what can be done to introduce cost-effective flood prevention and resilient flooding infrastructure, so as to help avoid a repeat of the current disaster.
In the context of more variable monsoons and more catastrophic flooding, the introduction of better warning systems and enhanced infrastructure is essential.
If the international community fails in this mission, societies and governments will be unable to respond to the devastating combination of changing environmental stresses, a growing population and geopolitical instability.
Lord Hunt is a former director general of the Met Office