Global warming, devotion, the lunar calendar: Why this will be one hot Ramadan 2010

Devout Muslims are waiting for the first sighting of the new moon, probably Tuesday night, marking the start of the fasting month of Ramadan 2010. This year's fast will be the first in almost 30 years that corresponds with the hottest days of summer.

This Ramadan, the fasting month whose call on Muslims to act with more charity is challenged by the crankiness brought on by going without food and water during daylight hours, presents one of the stiffest challenges for the devout in 28 years.

For most of the world's 1.5 billion Muslims, the fast will begin Wednesday at dawn (though some will delay a day if the new moon isn't sighted by a religious authority they follow). With the Islamic lunar calendar cycling through the solar Gregorian calender that the West uses roughly every 30 years, Ramadan now – and for the next five or so years – will correspond with the hottest and longest days of summer for most Muslims.

And, at least from a short-run perspective, those hottest days have been getting hotter. The mostly Muslim countries of Pakistan, Sudan, Iraq have all recorded their highest ever single-day temperatures this summer. The US National Climate Data Center, using both land and sea readings, estimated that the first six months of 2010 were the hottest on record.

August is not likely to slack off much, making Ramadan's requirement that nothing be consumed during daylight hours that much tougher. In Iraq, Ramadan may even see an increase in violence: US officers there say the start of Ramadan usually means more attacks, perhaps driven by the religious fervor of some of the militants.

To be sure, short-term temperature spikes don't necessarily correspond to long-term trends (though it appears this decade will be hotter than the 1990s, which in turn were hotter than the 1980s). But there's no doubt that it's going to be a grueling few Ramadans before the month corresponds with the cooler, and shorter, days of spring and winter.

While all this is leading to more grumbling in capitals from Cairo to Tehran, the rhythms of Ramadan will remain much the same, with shorter office hours, large family get-togethers to break the fast in the evening, and the central contradiction of the fasting month: People tend to put on weight more than any other time of the year, since they gorge themselves at their least active times of the day and generally eat richer and larger meals than for the rest of the year.

In medieval precincts of Cairo, dawn criers will still take to the streets in the dark, beating drums and calling out "it is better to pray than to sleep" to remind the devout to wake up, pray, and get something to eat before the sun rises over the city's ancient spires and the teeming warrens of downtown. In Jakarta (and many other cities), the charitable rich will be setting up chairs and tables outdoor, where the poor will be invited to buka puasa ("break the fast") for free at sundown.

From Damascus to Istanbul, central bankers and economists are bracing for the inevitable bump in monthly inflation driven by greater Ramadan demand for food and new clothes, and in some countries like Qatar, governments have tried to prevent price gauging by merchants by fixing the price of popular items.

Some accommodations are being made. In the United Arab Emirates, where August daily temperatures often top 110 and high humidity can make the act of breathing feel like sucking soup through a snorkel, a government-linked religious body issued a fatwa that told laborers that it is acceptable to break the fast if they feel the need to.

Ramadan is the holiest month of the year for Muslims because the devout believe that it was during this month in 610 A.D. that the Angel Gabriel, as an emissary of God, began revealing the Koran to the prophet Mohammed.

Exceptions from fasting are typically made for travelers and pregnant women. The global spread of Islam has also led to some interesting fatwas that will certainly be coming into play this year.

In towns in the Arctic Circle, Muslims will be facing 17-hour or longer days, and in a few years, when Ramadan falls during the solstice, there will be 24 hours of daylight for some. In essence, the guidance for Muslims is that they can reduce the length of their fasts to take into account the limits of the human body.