July 27, 2007: Ethnic "Arabized" tribes from Niger and Chad are crossing the Chad-Sudan border. "Arabized" is a vague term, but it usually means the tribe is Muslim. In Sudan it also usually means the tribe is "pro-Sudanese government." One nomadic tribe which regularly crosses the Chad-Sudan border is the Um Jalool. Since late 2004 Darfur rebel groups have claimed Um Jalool tribesmen have served with the various janjaweed militia groups operating in Darfur. The movement of the tribes has also sparked accusations that the Sudanese government is practicing more "demographic warfare." This means the government is moving pro-Khartoum groups into the Darfur region. This serves two purposes. The first purpose is to provide "settlers" to take over villages emptied by the militias. The second purpose is a little less immediate but is something on the minds of the Khartoum government. Ultimately there will be international pressure for a plebiscite to decide Darfur's final status" (to use the term that refers to the UN's process for determining what will happen to Kosovo). In other words, if the claims about tribal movement into Sudan are true, the Sudan government is importing pro-government voters. UN observers note that the tribal movements appeared to be "well planned." The most reliable figure is 75,000 people moving into Darfur. How will the rebels respond? A form of "counter ethnic-cleansing" could occur, where displaced Dafurians attack the tribesmen who have occupied their old villages. The possibility exists that these reports are overstate. Nomadic tribes do move from place to place, and have done so for centuries ­ long before the current political borders were drawn on maps.

The main reason behind all this is a population explosion. A thousand years ago, the population of Sudan was three million. A century ago, it was six million. Now it's 40 million. All this growth was because of Western technology and public health practices. The Sahel (the band of semi-desert land the stretches across Africa below the Sahara) has been dry for the last 1,500 years. During the last ice age, which ended 12,000 years ago, the Sahel was more like the American Midwest. But ever since the ice age ended, northern Africa kept getting drier and drier. That was happening even during the time of the Roman empire, and the people back then noticed, and even left us a few notes on the matter. All this has been well documented. There are too many people, and too little water, in Darfur. The government has moved out people they don't get along with (black Africans) and moved in people (ethnic Arab Sudanese) that do.

July 25, 2007: At least 170,000 refugees are "out of reach of food aid" in Darfur. Since July 10, nine food convoys have been attacked in the Darfur region. There is also an escalation in direct attacks on humanitarian workers. The convoys attacks are above the norm for a two-week time period. At least 77 convoys (of all types) have been attacked this year (including the nine since July 10). The UN (through the World Food Program) has approximately 700 trucks in the Darfur region.

July 21, 2007: Sudan's president Omar al Bashir paid a visit to Darfur. Bashir urged Darfurians to combat "tribalism and sedition."

July 20, 2007: Sixteen armed men attacked an aid convoy near Tawila (North Darfur state). The drivers were taken prisoner and then released after a ransom was paid.

July 19, 2007: The Sudanese government apparently nipped a coup in the bud. The Sudanese Ministry of Justice has stopped all media from reporting on a case involving 17 alleged conspirators.