Paying Attention to the History of Climate Change

One of the unfortunate consequences of the hyperbolic, circumscribed climate change discourse (It’s all hoax, No it’s not!) is that we don’t pay enough attention to the climate change that did happen in prehistory, specifically the mega-droughts that combined with other factors to cripple ancient empires.

These are complicated stories that are still being puzzled out by scientists, as I discuss in this longish piece at the Yale Forum on Climate Change & the Media. But I think these stories and the evidence of prehistoric drought are becoming clear enough for us to draw lessons from. Have a read and let me know over there what you think.

UPDATE: Via John Fleck, I see there’s an important new study on medieval megadroughts that adds to a robust body of literature.


Category: climate change, drought

Oh, the Horror!

In north Texas, a resident blanches at the idea of major water restrictions kicking in because of the area’s drought:

In Garland, it’s a major concern for resident Charlotte Piercy, who has lived in her neighborhood for 56 years. Piercy already hates her grass looking brown because of the Winter, but she fears, come the spring, it won’t get green again.

“I would hate to see us go to that stage,” said Piercy. “The neighborhood would start looking like grasslands, like dried up prairie lands.”

John Fleck tweets:

Note: You live in a dried up prairie.

 


Category: drought

These Bristlecones Are Talking

And they have a message:

Researchers say they have found new evidence of prolonged drought in parts of the West, suggesting megadroughts are not the rarity Westerners would like them to be.

Of course, there is already ample evidence for Westerners not to think this, but c’mon, who remembers what they had for dinner on Tuesday, much less how much it rained 800 years ago?

Then there’s all this climate changey stuff that people keep bringing into the picture, and it’s just…well…I bet some of my buddies out West can feel the hard reckoning in their desert-bleached bones.

There is an upside, though: Archaeologists in 3100 AD are gonna be feasting on the ruins out there. And a thousand years from today, I bet they’ll also be scratching their heads over the same thing we wonder now about the Anasazi and Hohokam: WTF were these people thinking?


Category: Archaeology, climate change, drought

Look on the Bright Side

Drought by area impacted is worst ever-though majority of US still drought free

From the Dept of Silver Linings


Category: drought

Romm: Global Warming is the Only Correct Answer

Just for kicks, here’s my revisions to the opening paragraph in this Climate Progress post:

Another week, another New York Times article Joe Romm post on extreme weather that fails to stretches climate science to simplistically connect the dots to global warming for the public.  The NYT Romm blew the Arizona wildfire story.  They He blew the Dust Bowl story.

And now, “one of the most influential global-warming blogs on the Internet” (according to Time magazine) has blown the Southwestern drought story. As Romm has so often reminded us, the media is remiss when it doesn’t connect disasters such as Australian wildfires and Russian heat waves to global warming. (The same goes for Arab revolts.) So, predictably perturbed at this NYT story, Romm titles his post:

NY Times Asks Why “Horrible” U.S. Drought “Has Come on Extra Hot and extra Early.” Their Answer is…La Nina, Of Course!”

Well, actually, that’s what NOAA’s David Miskus says in the NYT story:

A strong La Niña shut off the southern pipeline of moisture.

And, as I pointed out yesterday, that’s also what Climate Central’s Andrew Freedman reported in his WaPo’s Capital Weather Gang blog:

The drought was caused in part by La Nina conditions in the tropical Pacific Ocean, which altered the main storm track across North America, helping to steer storms across the northern tier, leaving southern areas desperate for rain. Although La Nina has waned, there are increasing signs that it may redevelop this fall or winter, according to the latest outlook from the Climate Prediction Center.

But if you absolutely, positively must mention global warming when discussing the Southwestern drought, Freedman shows us how to do it in a responsible fashion, in his next passage (my emphasis):

However, La Nina wasn’t the only force behind the drought, says [Marty] Hoerling, who leads a group of climate change attribution sleuths at NOAA. For now, though, the co-conspirators remain unknown. Although climate science research shows that droughts are likely to become more intense and more frequent in a warming world, particularly in the Southwestern US, observational evidence does not yet show clear trends in drought conditions in the U.S. to date.

Hoerling says his quick analysis led him to conclude that climate change has not played a major role in this event. “This is not a climate change drought by all indications,” he said, adding that this view does not in any way refute the fact that global warming is occurring, either.

Joe Romm, for all his blustery criticism of journalism, could take some pointers from an actual climate journalist like Freedman.


Category: climate change, climate science, drought

A Complex, Combustible Landscape

This nuanced statement by Tom Kenworthy, a former reporter, was spot on until the very end (my emphasis):

The reasons that the desert Southwest is having another extreme fire season are complex. They include decades of poor forestry and livestock grazing practices, misguided federal firefighting efforts that have prevented low-intensity fires in Ponderosa pine forests from clearing out underbrush and small trees, and prolonged, exceptional drought caused by climate change.

John Fleck, a science writer for the Albuquerque Journal, grasps the complexity of the fire story, and Andrew Freedman does a superb job unpacking the scorching Southwestern drought in a must-read post at the WaPo’s Capital Weather Gang blog:

The drought was caused in part by La Nina conditions in the tropical Pacific Ocean, which altered the main storm track across North America, helping to steer storms across the northern tier, leaving southern areas desperate for rain. Although La Nina has waned, there are increasing signs that it may redevelop this fall or winter, according to the latest outlook from the Climate Prediction Center.

However, La Nina wasn’t the only force behind the drought, says [Marty] Hoerling, who leads a group of climate change attribution sleuths at NOAA. For now, though, the co-conspirators remain unknown. Although climate science research shows that droughts are likely to become more intense and more frequent in a warming world, particularly in the Southwestern US, observational evidence does not yet show clear trends in drought conditions in the U.S. to date.

Hoerling says his quick analysis led him to conclude that climate change has not played a major role in this event. “This is not a climate change drought by all indications,” he said, adding that this view does not in any way refute the fact that global warming is occurring, either.

Hoerling noted that as average temperatures increase due to climate change, drought impacts would likely get worse. Drought plus heat “is just going to make a bad situation that much worse,” he said, since higher temperatures dry soils out much more rapidly. “We haven’t necessarily dealt with drought and heat at the same time in such a persistent way.”

He said the drought serves as a reminder that society needs to be more prepared for significant, relatively rare events such as this one, regardless of whether they are due to global warming or natural climate variability.


Category: climate change, drought, wildlife

Mega-Droughts Stalk the Southwest

A few weeks ago, I mused that the American Southwest may be on borrowed time. Forget that.

The Southwest is toast.

A new paper in Nature spells doom. From the abstract:

The potential for increased drought frequency and severity linked to anthropogenic climate change in the semi-arid regions of the southwestern United States is a serious concern. Multi-year droughts during the instrumental period and decadal-length droughts of the past two millennia were shorter and climatically different from the future permanent, ‘dust-bowl-like’ megadrought conditions, lasting decades to a century, that are predicted as a consequence of warming.

Nature’s Quirin Schiermeier has an article on the study, and this eye-popping quote from Richard Seager, a Columbia University climate researcher:

The drying we expect for the twenty-first century is entirely the result of increased greenhouse forcing.

But we’re not there yet, Seager tells Nature:

A signal of anthropogenic drying is emerging, but it is still small. I’d expect that by mid-century the human signal will exceed the amplitude of natural climate variability. Then we can safely say that the Southwest has entered a new climate stage.

UPDATE: Prehistoric drought in the SW is a big interest of mine, so I’m going to provide all the relevant press coverage links, as they come in. John Fleck, a science writer for The Albuquerque Journal, has a story and a post at his blog.


Category: climate science, drought, southwest

Let’s Talk Drought

Drought, like global warming, is a slow motion event that humans can’t get seem to get ahead of. Or properly grasp. For a good historical case study examining how the Maya, the Vikings, and the U.S. (in the lead-up to the Dust Bowl) each responded to drought, see this paper by Ben Orlove, who observes:

From the comparative history of the past, it can be seen how fragile human societies can be and how resistant they can be to changing established patterns of action; it can also be seen that most people somehow survive in both a biological and a cultural sense.

The big difference today, obviously, is that we know this history and also have some ability to see into the future, as this new study suggests:

The United States and many other heavily populated countries face a growing threat of severe and prolonged drought in coming decades.

What’s notable about this research by Aiguo Dai, a scientist at the National Center for Atmospheric Research (NCAR) in Boulder, Colorado, is that there’s a global warming angle:

The detailed analysis concludes that warming temperatures associated with climate change will likely create increasingly dry conditions across much of the globe in the next 30 years, possibly reaching a scale in some regions by the end of the century that has rarely, if ever, been observed in modern times.

Before going any further, it’s important to point out that modern times (especially in the U.S.) are not the best measuring stick, which this definitive paper succinctly explains in its abstract:

Severe drought is the greatest recurring natural disaster to strike North America. A remarkable network of centuries-long annual tree-ring chronologies has now allowed for the reconstruction of past drought over North America covering the past 1000 or more years in most regions. These reconstructions reveal the occurrence of past “megadroughts” of unprecedented severity and duration, ones that have never been experienced by modern societies in North America.

This in no way diminishes the threat of natural occurring droughts worsened by anthropogenic global warming, which NCAR’s Dai lays out in his new study. Those findings are bound to make a splash in the media and blogosphere today. To understand why, here’s Dai in an early MSNBC report:

We are facing the possibility of widespread drought in the coming decades, but this has yet to be fully recognized by both the public and the climate change research community. If the projections in this study come even close to being realized, the consequences for society worldwide will be enormous.

So it’s a safe bet that the hook to this story is going to be climate change. Fair enough. Dai makes that explicit in his paper (which people should read). But he also concludes on this note:

Given the dire predictions for drought, adaptation measures for future climate changes should consider the possibility of increased aridity and widespread drought in coming decades.

I don’t expect that message to be emphasized in the spot reporting of the study or much discussed by climate bloggers, but given the history of prolonged droughts and civilization, here’s hoping it echoes in the halls of policymakers and planners.


Category: climate change, drought

Africa’s Ancient Mysteries

This article by Roger Webster, a South African historian, is intriguing on several levels. I was drawn in by this opening:

One of the many aspects of history and archaeology that fascinates me is that, in many respects, archaeology becomes the verifier, or the destroyer, of history.

Be sure to read it all the way through to the haunting poem about drought that closes the piece.


Category: Africa, Archaeology, drought

The New Norm

The indispensable Jeffrey Gettleman has a heart-wrenching dispatch on Dot Earth:

We walked through a camp for displaced people, absorbing the human wreckage all around us. There were stick-skinny children with horrible, rattling coughs that sounded like an old Chevy Nova trying to start up on a cold morning. Emaciated goats snacked on piles of garbage, filling their stretched bellies with nothing more nutritious than black plastic bags. Families of ten packed into sweltering lean-tos made from sticks and cloth, many of them fleeing either war or drought, Somalia’s twin killers that have sent more than 20 percent of the country’s population on the run.

Gettleman then surveys Somalia’s desperately parched conditions and notes that

even the camels are dying, which really frightens people, because camels can plod along for days on just a sip of water. They are the last animals to keel over in the desert and disappear into the sands.

Now here’s the passage that makes this latest chronicle of Somalia’s seemingly endless tragedy horribly complicated:

True, droughts are cyclical, and various studies suggest that Africa has experienced parched epochs before. But many people here these days believe the extreme dryness may be evidence of climate change and leaders in far-from-industrialized Africa, which produces just a tiny fraction of the world’s CO2, are increasingly saying that their countries are paying a high price for greenhouse gases that are raising global temperatures worldwide.

Next, Gettleman quotes Nicholas Wasunna, an aid official in Kenya, who obviously combines these cyclical droughts with greenhouse gas-induced climate change to conclude:

This is the new norm. We’re going to be see more of these periods of intense droughts followed by intense rain,

to which, Gettelman then writes, ” is the situation predicted for East Africa this year.”

Okay, right here-this gray zone, where failed states, such as Somalia, collide with natural cycles of drought and the exacerbating factor of anticipated climate change-is where environmental security experts should step up their game and weigh in with policy prescriptions. Yes, we know that this might be a case study of “climate security,” the kind that we’ll see arising in other politically unstable countries, which the CIA will now be examining more closely for our own national security purposes.

But if we know Somalia’s misery owes largely to its decades-long failed state status, an enduring human tragedy now compounded by a four-year drought, and perhaps worsening environmental conditions from global warming, well, what’s the foreign policy/humanitarian strategy for tackling all these disparate “forcing actions” in a coherent manner?

After all, it is presumed that the carbon load already in the atmosphere is going to lead to “irreversible climate change,” no matter what happens in the U.S. Congress or in Copenhagen this year. So what’s the environmental security game plan for Somalia and other countries like it?


Category: drought, environmental security