While Tom Ricks is away from his blog, he has selected a few of his favorite posts to re-run. We will be posting a few every day until he returns. This originally ran on July 29,2011.

By Eric Hammel
Best Defense guest columnist

Over the past year, I've worked the vast security implications of global climate change into a few comments on The Best Defense, but they haven't taken hold. I cannot fathom the prevailing so-what attitude as the FEMA-grade weather disasters mount toward becoming serial and routine occurrences. It's here now, for all to see.

Tens -- perhaps hundreds -- of millions of heat, drought, flood, and famine refugees are probably going to be shaken loose within a decade. (Some estimates say half of humanity -- 3,000,000,000 people -- will have to move or die just from heat-related causes.) Thanks to topsoil erosion via drought and helped along by deadly, unstoppable tornado clusters and unlivable ambient temperatures, the bulk of farming in North America will shift northward and most likely will become restricted to a narrower band in the upper Midwest and on into higher Canadian latitudes-assuming there is sufficient rainfall there. Sea-level rise from melting glaciers on land will soon be poised to shake loose uncountable refugees from drowned coastal regions, where most of the world's people live. If the warm North Atlantic conveyor current is halted or recedes southward due to desalinization via the Greenland freshwater ice melt, the Canadian Maritimes, New England, and northwestern Europe will probably experience unbelievable winters and might (this is counterintuitive) freeze over.

Global famine is going to force the use of our military as a police force organized to feed unknowable masses of people (until cold reality sets in as reserve food stocks evaporate). I believe that North America's first up-close brush with famine-motivated mass migration will take place in northern Mexico and on into the U.S. border states. (Refugees fleeing in the wake of the collapse of Mexico's central government could precede drought- and heat-related dislocations. Are we prepared to handle such a dress rehearsal?)

The only force on Earth with the inherent capability to police, process, house, feed, and move refugees on a mass scale is the U.S. military, but, though its reach is global, its capacity and stamina are nonetheless limited, probably to one or two major disasters at a time, not the overlapping rolling meta-disaster climatologists predict. (Remember, the only components of the Katrina effort that worked at all were the military responses, beginning with Coast Guard helicopters.)

The implications for military use alone in the looming weather-related crises are mind-boggling, but no one appears to want to face up to them with an action plan, a doctrine, a list of precepts. I find it worrying to the nth degree that there is absolutely no public discussion. Have the relevant agencies studied it all already-and thrown up their hands? I already know from a series of phone calls to relevant local and state agencies that there is no actual integrated plan in place to respond to high-impact earthquakes in major California population centers. The "plan" is to play it as it lays. And I sincerely doubt that a repeat of Katrina would be met with an effective plan based on lessons learned.

Can we bring this out of the shadows, and least in this venue?

Eric Hammel has written more books about the U.S. military in Vietnam, Korea and World War II than most people have read.

Basra continues to perplex me. Weird news over the weekend out of there, as  police fired at or over (not clear) demonstrators upset by the lack of electricity.

Meanwhile, my CNAS colleague Will Rogers checks in with other resources and utilities news. He reminds me of something I read years ago in a history of Iraq, that life there has always been a struggle against the people who live just upstream of your irrigation canal and can cut off your water-a tool the British used effectively in putting down the 1920 Shiite uprising.  

By Will Rogers
Best Defense deputy chief, Iraqi natural resources bureau

In Iraq, a country where one in four citizens do not have access to safe drinking water - let alone enough water to irrigate their crops -- water shortages could drown any hope of long-term, meaningful reconciliation between the Iraqi people and the government.

Many Iraqis have been pleading to Baghdad to devote more resources to shore up the country's crumbling infrastructure and unsustainable water management policies in order to effectively tackle the chronic water challenges that have been exacerbated by four-years of drought. "If our government was good and strong, we would get our [water] rights," one Iraqi told The New York Times recently.

Ali Baban, Iraqi Minister of Planning and Development Co-operation, warned last July that Iraq's intense drought conditions could push the frail state to a breaking point. "We have a real thirst in Iraq. Our agriculture is going to die, our cities are going to wilt, and no state can keep quiet in such a situation," he cautioned. But with the government still in limbo after the recent March 7 election, it is unlikely that Baghdad will have the capability or capacity to address these water woes anytime soon.

Read on

With the polar icecap shrinking, the Canadians are gearing up for a confrontation eventually over whether other nations' ships will need their permission to transit the Northwest Passage. They say it's an internal waterway; we maintain it's an international strait.

Here's an article exploring how the Northwest Passage is central to Canadian identity. I think we'll be seeing a lot more of these in the future.

This is one way the BP oil disaster is going to have second and third order consequences: Anytime the United States asserts a right to passage, people can just hold up a photo of the oil mess in the Gulf of Mexico, and say, "Hey, you guys can't take care of your own waters, so stay the hell out of ours."