Discovery News: Earth Impacts News

Wildfires & Warming: Nope

As promised, I'm finally getting back to that matter of wildfires and global warming. What I've gleaned from the research over the years is that wildfires generally have no long-term effect on global warming, despite releasing tons and tons of the greenhouse gas carbon dioxide. How can this be? It's pretty simple. The carbon locked up in plants is only recently extracted from the atmosphere, unlike the carbon from fossil fuels, which has been out of circulation tens to hundreds of million of years. Living plant carbon is only months, years or decades out of circulation (the age of the plant, in other words). So while it's certainly added in a big way to the atmosphere when plants burn, it's not a big change in the overall, long-term carbon budget. This, by the way, is also the reason why buying carbon credits that are based on the planting of trees to offset carbon emissions is considered pretty darned questionable. A drought and a lightning strike is all it takes to put that carbon right back into the atmosphere. It's not a very reliable strategy for lowering atmospheric carbon, in other words. The other thing fires do is make a lot of smoke which, ironically, cools the planet's surface. The trick is that the cooling effect of smoke lasts only a few weeks, while the warming effects of carbon dioxide can last a century or more.  Another complication is that global warming is expected to cause more droughts and fires, which could seriously alter the carbon budget, which could make wildfires a player in global warming again. As you can see, there are a lot of subtleties in all of this and a lot of unknowns. I've probably oversimplified things and might have put my foot in my inexpert mouth already. If so, let me know so I can find a way to pull it out again.

A Thumbnail History of Wildfire & Humans

Here's a little tale I've learned over the years from listening carefully to some of the best fire ecologists and fire historians on the planet: Once upon a time the land burned without any human intervention. Plants and animals adapted to these periodic blazes. Then humans discovered that in many places -- like California, South Africa and Australia -- burning created a nice, open landscape which better served our needs. So for several thousand years we burned the land more and the animals and plants adapted to these more frequent blazes. But then, rather abruptly, the European culture of land management spread around the world. Fires on the land were forbidden and moved into the hearths. Lands were managed to minimize fires. Finally, in most developed countries those wood-burning hearths gave way to gas, oil, coal and electric "hearths" -- all or mostly fossil-fuel based power sources. We just dropped the fire stick altogether, in other words. At the same time, we neglected our fire-adapted landscapes, except perhaps for the fire-breaks hacked our of the brush for several meters around our exurban homes. The result is that the land is either it is heavily managed, like farms, to reduce excess build-up of fuels (a.k.a. grass, wood, etc.), or periodically subjected to "prescribed burning," or it just sits there building up a load of fuel that either rots or burns in a hellacious firestorm. The end. Whether or not you believe this tale, you can learn more about the history of fire on every continent (with the exception of Antarctica), by reading the book World Fire, by fire historian Stephen Pyne. It's an eye opener.

Smokey Doppelganger

In case you haven't seen them yet, the NASA images of the fires in Southern California are show stoppers. The gigantic coils of smoke pouring out hundreds of miles over the Pacific are a clue to the size of the fires. But I have to admit, they are not unprecedented. Just for the sake of comparison, check out the NASA images of fires from almost exactly four years ago. See any similarity? It's a different set of fires burning in 2003, but the same winds, those darned Santa Anas, stoking the flames. I remember those dry winds well from growing up in Southern California. They shake loose a year's worth of dust and debris piled up by easterly onshore breezes and blow it all out to sea, along with the smog. You can see the mountains for a change. It makes you sneeze and chaps your lips, that desert air, but I loved them as a kid (perhaps that's why I now live in New Mexico). Then there are the fires, of course. Hard to love them when they're burning up homes, but the fires are inevitable, as fire ecologists tell us and even have interesting connections to climate change (more on that later). The greener the March, the redder the October. The more years Smokey Bear prevents those fires, the greater the blaze will be. So those great plumes of smoke over the Pacific are really not so new at all. Just our new view of our old adversary.   

Short answer to that infernal question

It happened again today. I was asked that infernal question which is impossible to answer while, for instance, standing with other parents under the manic gaze of a giant plastic grinning rodent, trying to keep tabs on pre-schoolers running wild at a pizza/amusement/ADHD establishment. This time it was Michelle who asked, an intelligent mother of two and nursing student who is well grounded in science and no fool. "Larry, I've been meaning to ask you about global warming...." Despite writing about global warming from just about every angle, I always feel like I'm grasping at a million feathers in a whirlwind when I try to explain to folks what's going on with our planet's climate. It's not that there's nothing to say. It's that the arguments and the evidence are so overwhelming and piling higher every day; I don't have a clue where to start. So like always, I just dove in, jumping from one thing to another -- the out-sized million-year carbon dioxide levels, grievous changes in polar regions, the unlikelihood that we could pull millions of years worth of sequestered atmospheric carbon out of the ground and dump it into the air over a few decades without something like this happening.  In the end, however, I deferred. I suggested Michelle simply rent Al Gore's movie, An Inconvenient Truth. Regardless of anyone's opinion of Gore personally or politically, the fact is he does an excellent job explaining global warming to the non-earth scientist. I know this because communicating Earth science is the ONLY thing at which I'm genuinely an expert. So take it from me, if you want to learn what all this global warming hoopla is about, just watch the movie. Then we can have a darn good chat.

The Worst of Times: K-T Still Mysterious

There's a very simple rule about evolution that's often forgotten or perhaps ignored because it's so darned depressing: For anything to evolve, a whole lot of species have to go extinct. In the school of evolutionary hard knocks, extinction is a failing grade. You can't  move onto the next grade -- you're out, fossil fodder, you're (pre-)history dude. Adapt or die. Those are the only choices. Nowhere is  this cheery bottleneck of life more glaring than in the mass extinction events that pepper Earth's history. These are, to carry the school analogy to an extreme, the SAT's of evolution. The most famous of these is the Cretaceous-Tertiary boundary, 65 million years ago. It was the death-fest which ended the reign of dinosaurs, of course. For almost 30 years now folks have been pretty content with the idea that a meteor impact caused that die off. But did it? I was reluctant to accept the meteor idea back in the 80s. Seemed a little too sexy and there was a lot of political noise at the time about "nuclear winters", which seemed to piggy back on, and then reinforce the meteor impact mass extinction idea. So it has been with some interest that I've followed the work of Princeton's Gerta Keller and others who believe they have evidence of the Chicxulub meteor striking too early. They say something else did the global murdering. The leading alternative, to date, is the Deccan Traps of India. These are gigantic flood basalts which erupted and flowed across India at the same time dinos died out. The evidence for the Deccan Traps role in the K-T mass extinction is mounting. Will Chicxulub be dethroned? Probably not this year. But stay tuned for the latest in this debate which will likely raise voices and eyebrows at the Geological Society of America meeting, which starts Oct. 28.

The 12 Ways, Specifically

Okay, okay, I will save everybody some trouble and reveal the 12 ways New Orleans is sinking, according to geologist David Rogers of the University of Missouri-Rolla. Mind you, below are my translations of his geologese. To get it straight from the horse's mouth, check out his abstract for the coming meeting, or a pdf presentation of his I just found. Read 'em and weep: 1) Bending of the crust under the ever-increasing weight of Mississippi muds.  2) Bending of the crust from the weight of squished-together blocks of river sediments. 3) Slumping of large blocks of land into the Gulf of Mexico. 4) Drainage of old swamp and marsh deposits which squeezes underlying clays. 5) Shrinkage of drained peaty soils (by chemical oxidation). 6) Compaction of soils by builders piling up fill materials on top of them. 7) Compaction from the added weight of roads, buildings, etc. 8) More roads and buildings covering the ground, which block the way for rain water to percolate into the ground and recharge the way for water to percolate down and educed groundwater recharge because of increase in impermeable surfaces. 9) Extraction of oil, which allows the very small, but innumerable spaces between the grains of earth, once occupied by oil, to collapse and so compact even very deep sediments. 10) Extraction of gas, which works the same as in number 9. 11) Extraction of groundwater, also like number 9. 12) Changes to salt deposits which move the more buoyant materials seaward. Had enough? Sure makes me want to sing the Blues. 

12 Ways New Orleans is Sinking

There’s a lot of contention about the Mississippi Delta these days. Some folks say it’s hopelessly sinking and should be abandoned. Others want to pour billions into massive engineering projects to fight off sea level rise and the ongoing subsidence of the land there. I’ve covered this matter for at least five years now, as I was reminded by a reader who pointed me to my own article forecasting the Katrina disaster three years before it happened. But I’m still torn about what we should do. On one hand I sympathize with displaced people of that region and respect their sustained fighting spirit and determination to rebuild. On the other hand, I was trained as a geologist and I can’t help but see how inevitable the sinking is. There are, after all, sunken cities on the Nile Delta and other examples of human settlements which stood in the way of geological change. Is this any different? Is it really courageous to fight a geological process or just foolhardy? Me, I’m undecided. For anyone who wants to take a closer look at this complicated issue, there is a fellow at the University of Missouri who is slated to give what appears to be a pretty balanced presentation on the matter at the meeting of the Geological Society of America later this month – including a handy list of the 12 ways the Mississippi Delta is sinking.

Earth: Anytime, Anywhere

An old buddy of mine used to pull this prank when he was a kid. He’d call the local pizza place that advertised they’d deliver “anytime, anywhere.” After confirming that they stood behind their ad, he’d order a pepperoni with olives for the late Jurassic on the west coast of Gondwana. As phone pranks go, it was a bit more Lisa Simpson than Bart: Nerdy in a rock-hammer, hiking boot, geological sort of way. Well, I’m pleased to say that the prank stops here. I can actually deliver where pizzerias cannot (WOOHOO!). That’s right, on this blog we’ll be wandering the Earth from at least five billion years ago through several billion years in the future; from her still mysterious core to the outer reaches of her magnetosphere. And there couldn’t be a better time. In the past few years the importance of Earth sciences has really come home to folks, at least those who are paying attention (the rest, alas, believe Earth is just 6,000-years-old and that Alley Oop is historical fiction). It wasn’t just a fluke, after all, that a bunch of Earth scientists and Al Gore just won the Nobel Peace Prize. The Earth is hot -- pun intended.