Millan Millan and the Mystery of the Missing Mediterranean Storms, Part II

In which Millan Solves the Mystery by Reading the Land

Welcome to part II of Millan Millan and the Mystery of the Missing Mediterranean Storms. In part I we followed Millan’s early career as he encountered, in the early 1970’s, the traditional two-part approach to climate, which Millan refers to as “two legged:” a leg for atmospheric carbon dioxide and the greenhouse effect, and a leg for land change (disturbance) and water-cycle effects. Here we step forward to the mid-1990’s to see how Millan, by understanding the role of landscapes in the climate system, solved the mystery of why the summer storm regime was collapsing throughout the Western Mediterranean Basin.

As we will see, the processes he uncovered bear implication well beyond the Mediterranean. For instance, when in 1995 he delivered his results at a symposium in California, a regional official with the US Forest Service said: “If what you say is true, California is in a lot of trouble in twenty to twenty-five years.”

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Millan Millan is a highly technical and practical scientist, steeped in physics and applied meteorology, and even holds an engineer’s stamp. Yet he turns poet when describing how soil, water and plants all work together to recycle water and regulate climate, employing the tercet: water begets water, soil is the womb, vegetation is the midwife.

What he means by water begets water is that healthy landscapes seem to grow water. Of course, water just can’t be created. There’s a set amount on earth, the same since the dinosaurs, and though we think of it as spread amongst clouds, oceans, lakes, rivers and glaciers, it is also inside living things. Humans are 60% water, birds 75%, fish 70-84%. A typical cat weighs in at 67%, while plants and trees are almost entirely water, 80 to 90%. How much water a landscape can hold is therefore proportional to how much life is in the landscape and soil to hold it. This water, once held, is transpired by vegetation back into the atmosphere as vapor to make clouds and future rain. Like this, the same water is recycled over and over, up and down, across landscapes. Though it used to be thought that virtually all inland water came from large water bodies and atmospheric circulations, it’s now realized that 40-60% of most rain comes via this recycling, increasing the farther inland you go. It’s called the small water cycle, and in some places, like the arid Sahel, it provides up to 90% of the rain.  The more life in a landscape, the more water it can “milk” from ocean flows. It’s a self-amplifying circle: water, through life, begetting more water, begetting yet more life, gathering yet more water, and around it goes, the result being climate-cooling and moderation. 

Soil is the womb because it holds the water. But here again it is really life holding the water, the rich below-ground microbial community which makes the difference between compacted, water-repellent dirt and clumpy absorptive soil. Picture soil as a sponge, held together but full of tiny cavities. There are grains of sand, clay, and minerals within that matrix, but what binds them into a sponge is life, an astounding plethora of the invisible and nearly invisible: protists and bacteria, nematodes and soil mites, and up to eight miles per square inch of fungal hyphae. It is their exudates and decaying bodies which not only glue the particles together, but hold them apart, making room for the water so crucial to life. When it’s all working properly, a very fortuitous feedback loop appears—the more carbon (life) in the soil, the more water the soil can hold. The more water in the soil, the more vegetation it can grow. The more vegetation it can grow, the more moisture it can feed the sky and the more carbon it can draw down into life and soil. It’s a virtuous cycle, “begetting” water, sequestering carbon, unseen and underground, womb-like.

Vegetation is the midwife because it delivers the water to the atmosphere as vapor, where it rises, condenses, and falls again as rain. But vegetation doesn’t only send up water vapor, it also delivers the seeds of future rain drops, called cloud condensation nuclei. These are microscopic grains of various biota, such as bacteria, fungal spores, and released vapors, all of which have uniquely low freeze thresholds, hastening the vapor’s condensation from vapor to ice to water and its subsequent return to land as rain. Clever, these living landscapes: they not only send the water up, they bring it back down.

You’ve probably noticed water features prominently in this analysis. That’s because from the standpoint of climate, water is elemental. For one thing, it has the highest heat capacity of any common earthly substance and can therefore move massive amounts of heat around. But as previously mentioned, water has an additional ability: to phase-change, to go from water to vapor and back again, exchanging heat at each juncture. Water is the shapeshifter of climate, dancing between rising vapor and falling rain, keeping things cool in the process.

Here's how it works. When water goes from liquid to vapor (evaporates) there is a cooling, no different from what we feel when we sweat in a breeze. That’s because the phase-change from water to vapor requires energy, drawing it as heat from the surroundings, which is felt as cooling. The heat required to turn liquid water into gaseous vapor, 540 calories per gram water, enters the vapor as a chemical potential called latent heat, like a spring pulled back. When the vapor rises and condenses back to liquid, the equation reverses, the spring rebounds and the same heat is released, only higher in the atmosphere, where it is much cooler. Though most of that heat will return to earth miles, even thousands of miles away, some will escape.

Scientists use the term transpiration for this ability of plants to turn water into vapor, but it can also be thought of as a kind of sweating. Since green is a darkish color, the tree or plant is not only absorbing sunlight for photosynthesis but is also absorbing a good bit of heat. To get rid of that heat, it basically sweats, just as we would do in a dark shirt under a hot sun. Under each leaf and needle are thousands of microscopic pores called stomata, which release moisture during the daytime, keeping both the plant, or tree, and its surroundings cool. Tremendous volumes of water are involved in this process; 100 liters per day for a typical tree. A gram of water requires 540 calories to evaporate. At 100 liters/per day for a typical tree, that translates to a cooling equivalent of 54,000 kcal, or 2 hotel air conditioners running all day. Add the evaporative cooling of soils and you have a sense of just how powerful a forest or woodland is at cooling its surroundings.

With Millan’s tercet in mind, let’s look at what happened in the Western Mediterranean Basin, that portion of the Mediterranean west of Italy, particular the area around southeast Spain, where we humans have been, well, changing things for a while.

The Western Mediterranean Basin was once lush, with vast oak forests, springs and extensive coastal marshlands. Early Romans said a squirrel could travel limb to limb from the Pyrenees to the Strait of Gibraltar and never touch the ground. But around two thousand years ago that began to change with the steady spread of the Roman Empire. Marshes were drained first to counter endemic malaria, then for agriculture, with widespread deforestation and mining in the mountains. By the 16^th century much of the oak forests had been cut and lowland agriculture was spreading higher into the mountains, along with grazing and further land disturbance. Then came the industrial revolution, followed by modernity. In the 1950’s, mass urbanization sealed yet more land as Spain industrialized. A booming tourism industry was particularly devastating for Spain’s coastal marshes, covering key links in the water cycle with parking lots, sandy beaches and hotels. But the deathblow came in the early 1970’s when, due to unrest in the Middle East, massive petroleum infrastructure was moved across the Mediterranean Sea from the Middle East to the shores of Spain, France and Italy, resulting in “intense industrialization of the coasts.”

Millan confronted a basin-wide hydrologic system in the final stages of collapse. The midwives had not only been cut, but the climatological regime by which the oaks of old could live had long passed. In its place was a much dryer climate, supporting mostly pinyon and scrub, the maqui. The soil womb was mostly sealed under concrete or eroded away, stretched in places over bare stone. A classic example of how badly things can go wrong is found in the nearby province of Almeria. In the 1850’s its dense oak forests were clearcut to stoke the furnaces of lead smelters. The collapse to desert was so profound that the area eventually became a film locale for spaghetti westerns. Millan has come to believe the entire Western Mediterranean Basin is at such a tipping point, on its way to becoming an Almeria style desert, a point from which it is very difficult to return. “Once you hit rock,” he says, “you’re done.”

Early in his analysis, he uncovered a key detail.  When the morning winds came in, their water content was 14 grams per cubic meter of air, not enough to form clouds, which under those specific conditions would require a moisture level of 21 grams water per cubic meter. The rest of the moisture, 7 grams per cubic meter, would have to come from somewhere else, which brings us back to the land.

At one time, that same sea breeze passed over vast coastal wetlands stretching miles inland, gathering the water vapor rising off of them. Then, proceeding toward the mountains, it would gain even more moisture from the great oaks, each a water tower in its own right. By the time it was climbing up the last high ridges it was saturated not only with moisture but cloud condensation nuclei. One can imagine the thunderheads billowing up, stacked plumes rising two miles in the air, releasing their latent heat to dissipate high over the mountains while dropping cold rain back on the land, rehydrating the vegetation and recharging the aquifers and marshes.

Now, however, rather than marshes and oaks, the sea breeze encounters concrete, steel and degraded landscapes. Not only is it deprived of the moisture it needs to make storms, it’s buffeted by the heat rising off the man-made materials, gaining 16^oC before reaching the mountains. What finally reaches the hills finds shrubs and scattered pinions, skeletal remains of the ancient oak forests. Not only is there too little respiring life to provide the missing 7 grams water per cubic meter air to make the rain cloud, but the intense heating of the air mass means it requires even more moisture to produce rain clouds. The pattern now is a few clouds gather in the late afternoon, rise, spread, then wisp away. The warm, moist, now-polluted air, instead of releasing its gathered heat and dropping rain on the land to replenish the system, merely flows back over the Mediterranean Sea.

This roughly explains the loss of summer storms, but the process doesn’t end there. The moist, polluted layers of air pile up over the Mediterranean Sea, layer upon layer, day by day. Those layers, soupy with powerful greenhouse gases like water vapor and ozone, steadily warm the sea below, so that by the end of summer the warmed sea begins supercharging coastal storms, as well as storm tracks that curve down over the Mediterranean on their way back up to central Europe. These storm tracks gather up the warm, moist layers and become supercharged as well, contributing to the devastating floods in Eastern Europe.

So where did the summer storms go? They left with the forests, soils and wetlands. Why are the coastal storms getting worse? In part from a sea-body warmed by the hydrological effects of ruined forests, soils and wetlands. Where are the drenching central European rains coming from? In part from moisture picked up over the Mediterranean that should have emptied out as rain over the inland mountains. What to do about it? One, stop ruining forests, soils and wetlands. And two, start restoring forests, soils and wetlands. Or as Millan puts it in his own imaginative way, start “cultivating storms.”

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By 1995 Millan had finished his analysis and began publishing his work and making presentations. It was a heady time. Nobel laureate Paul Crutzen reportedly considered it the most important climate science in twenty years. His mentor, Ted Munn referred to his use of traditional meteorological charts as a kind of proof, a “smoking gun.” High level officials within the European Commission were excited as well, and soon asked him to contribute chapters to their climate reports explaining how climate models were missing land effects, and to talk to the modelling community about the problems with their models. This, though, is when the troubles began. The modelers didn’t appreciate his insights as to how their models were off, many simply refusing to believe what he was telling them. For Millan, these were not pleasant assignments, and it was about to get worse.

He was soon invited by the IPCC to contribute to their Third Assessment Report, scheduled for publication in 2002. But he ran into the same conflict. The modelers there “questioned every result we presented,” he said, describing a time of endless argument and report generation, which he eventually grew impatient with, leaving the IPCC.  “I had 80 mouths to feed at CEAM (Mediterranean Center for Environmental Studies) and no time to argue,” he recalls.

The political environment didn’t help. Politicians much preferred the narrative of the modelers to what Millan was telling them. The last thing a politician wants to hear is that wherever they develop land, whether for a school or a factory, they damage the climate. They preferred what the modelers offered, a globally dispersed problem for which they had no specific local or regional responsibility. All the better if it allowed them to promote growth and burnish their job-making credentials. Indeed, the solution framework presented to them— “green” energy—allowed them to not only promote development, but at the same time be “green,” a politician’s dream-come-true.

But let’s briefly consider here the two sides of this scientific argument.

On one side we have Millan Millan, who’s conclusions are based on eighteen years of physical data utilizing assorted air balloons, gauges, instrumental aircraft and over 50 meteorological towers. Further, it incorporates and is informed by the lived experience of locals, particularly the elders who observed the changes the longest. And it relies on a minimum of computer modelling. That is, it is empirical, based on physical evidence not theoretical equations, using standard, long-tested meteorological methods.

On the other side you have individuals sitting behind computer screens, in the placeless place of a computer model, consulting what is ultimately a simulation.

Which approach seems more reliable?

Other questions come to mind, like “what happened to the land-change leg of climate?” Or “how many other regions around the world are being misread by global computer models, the local nuance of landscape dynamics missing from the picture?” And perhaps most importantly, “why don’t we know about any of this?”

It turns out these questions aren’t mysteries. They have answers, as we will find out in the third and final installment of Millan Millan and the Mystery of the Missing Mediterranean Storms, coming soon.