NEWSBYCHRISTOPHER MIMS

Did Nashville flood because of global warming?

The short answer is the well-worn, "no single extreme weather event can be directly attributed to climate change, because of the inherently chaotic nature of the global climate system. But the Nashville floods are certainly characteristic of the type of events we expect to see more of in a warmed world."

But the long answer is, basically: Yes.

According to Rich Hayes, deputy communications director at the Union of Concerned Scientists and a Nashville resident, "A report by 13 federal agencies last year found that one of the most pronounced precipitation trends in the United States is the increasing frequency and intensity of heavy downpours. More precipitation is falling during very heavy events, often with longer dry periods in between.  Climate models project more heavy downpours and fewer light precipitation events."

Understanding why this is the case requires grokking a single fact of basic physics – the sort we'd all have memorized by heart if our leaders wise enough to prioritize climate change at the top of the list of threats to this country and curious enough to educate themselves about its particulars.

Warmer air doesn't just hold a little more water. It holds a lot more water. Exponentially more. Here, courtesy Wikipedia, is a graph of the change in the maximum amount of water vapor the air can hold as temperature increases. (Click for a larger image.)

"If the fossil fuel emissions that cause global warming continue unabated, scientists expect the amount of rainfall during the heaviest precipitation events across the country to increase more than 40 percent by the end of the century," says Hays.

And those future projections are simply a continuation and acceleration of a climate change trend/impact that is already in progress. Hays continues: "Very heavy rain and snow events, defined as the heaviest 1 percent of all precipitation events, now drop 67 percent more water on the Northeast, 31 percent more on the Midwest and 20 percent more on the Southeast than they did 50 years ago."

So, was Nashville's record flooding caused by global warming? If you're asking that in the sense of "If we stop heating up the planet, can we save ourselves untold billions in damage due to flooding, as well as hundreds or thousands of lives lost?" Then yes, absolutely. And frankly, I can't think of any other way in which that question can be answered that is not an equivocation designed to throw a bone to the delayers and deniers, whose goal, intentional or not, is death, destruction and impoverishment - through inaction.

Photo credit: president raygun

Americans currently spend a smaller percentage of their household budget on food than at any other point in history. There are about 40% more calories available per person in the U.S. today than there were before 1980.

So even though climate change is going to affect our farms and food security, we've got a long way to fall before we're shedding pounds like Cubans did when the Soviet Union cut off their supplies of subsidized fuel.

Not so the developing world.

The world's poorest 2 billion, many of them subsistence farmers or slum dwellers who can barely afford food as it is, are staring down the barrel of a gun when it comes to climate change and food security.

It's a given among those who worry about the tradeoff between food and fuel epitomized by ethanol that the notion that the U.S. might produce even more of the stuff – say, in an effort to wean ourselves from offshore drilling – is horrific.

First off, there are the environmental consequences of ethanol. It's made from corn, and corn requires mind-boggling amounts of fertilizer, a lot of which ends up forming a giant dead zone in the Gulf of Mexico that kills sea life just as dead as an oil slick.

However, I've recently come to question, just a little bit, the notion that turning all that corn into fuel will ultimately lead to an increase in world hunger.

One of the things we've long known about climate change tipping points is that we won't know when we've crossed them. Like any other inflection point in a long-simmering trend – the economy, peak oil, the waning appeal of certain aging rockers  – these transitions from avoidable catastrophe to unstoppable disaster are only visible in retrospect. I submit that in as much as the most significant tipping points in the climate change system are, like the problem itself, anthropogenic, we've just crossed one.

For those of you who aren't familiar with the Congressional dithering over the forthcoming climate bill, Chris Santiago has been covering it for Change.org: the bottom line is that for purely political reasons Harry Reid (D-NV) bumped up submission of the immigration bill, something Republican co-author of the house climate and energy bill Lindsey Graham is loathe to support.

This is a problem, because without Graham, there are pretty much zero Republican supporters for a climate and energy bill. With him, perhaps an extra one or two could be brought on-board – enough to get it passed, anyway.

Now the climate bill is back, sort of, but the odds that it will come to the floor of the House, much less pass, are worse than ever.

Wednesday's announcement that the U.S. Federal Government had finally, after nearly 10 years, approved the nation's first offshore wind farm marked the end of a long, strange journey for what should have been a straightforward move to initiate the clean-energy revolution favored by an overwhelming majority of Americans.

The forces arrayed against the project, known as Cape Wind, included the usual suspects — noted TeaBagger Scott Brown has some vague, hand-wavey objections to it that appear to derive more from political expedience than his professed love of the rights of Native Americans, which he claims the windfarm will infringe — and one that has always struck me as more than a little bit peculiar: Robert F. Kennedy Jr.

Climate scientist Andrew Weaver is suing the conservative Canadian newspaper the National Post for libel. His beef: The paper published four articles that contain patently false information, with intent to damage his reputation in the eyes of the public.

The claims are varied, but here's one you can look up right now: was Andrew Weaver planning to leave the International Panel on Climate Change, where he's had a leadership position for some years? Weaver says no. (The full complaint is available at DeSmogBlog.)

Canada's libel laws derive from the same Common Law as the U.K., which has a looser standard than the United States' rather stringent test for what constitutes defamation. In other words, it's much easier for Weaver to win this case on that side of the border.

The suit raises the question: Are the courts a venue for dealing with climate change disinformation? My first instinct is "no," simply because the majority of it tends to originate in the U.S., where we proudly defend the right of all crazies to say any damn thing they please.

And that's a good thing. Because if recent events — such as Texas' attempt to use Climategate as a pretext for suing the EPA — tell us anything about the nature of Americans, it's that the threat of legal mutually assured destruction is no protection whatsoever, and that the ability to sue over the validity of claims related to climate change will surely be used by both sides of the debate.

Science forbid that the various energetic deniers out there should get it into their heads that they have another means to harass scientists besides endless requests for every scrap of information available under the Freedom of Information Act.

Photo credit: dutchlad

Science journalist Eli Kintisch's new book Hack the Planet explores the emerging science of geoengineering — its promise, peril and inevitable use as a political cudgel by both the left and the right. I recently caught up with him on an Amtrak ride up to New Haven, on his way to give a talk on geoenginnering at Yale.

A survey announced at the recent Asilomar meeting on geoengineering revealed that 97 out of 100 people cannot correctly define the term "geoengineering." Do you find yourself doing a sort of 101 on it a lot, just teaching people the basics?

Very few Americans know what geoengineering is. It's striking that in three to four years something that was on the periphery of science has become something that the Royal Society and The National Academies of Science and AGU and mainstream science organizations are saying we must study.

What kind of responses do you get when you talk to audience about geoengineering?

I tend to find that the more knowledgeable the audience is about the probability of climate change, the quicker they come to the conclusion that this is a regrettably required topic for scientists and the public to think about.

If you want to be culturally literate about climate change, there are two books that you must read. The first is Mark Lynas's Six Degrees. The other, which just hit the stands yesterday, is Straight Up, the second book by Joe Romm, who was Acting Assistant Secretary of Energy for Energy Efficiency and Renewable Energy during the Clinton Administration. It represents the best of his blog Climate Progress, lightly edited and presented so accessibly that even veterans of that site will find it informative. No one in the public eye understands climate change, its solutions and its detractors better than Romm.

Here is what Joe Romm says in Straight Up that is worth repeating over and over again, until everyone with any decision-making power whatsoever knows it:

1. If we want to avert disaster, we must stabilize the earth at 450ppm CO2 by 2050. This means reducing our carbon emissions by 80 percent by that date.

2. On our current trajectory, climate change will lead to much worse than most people suspect. Impacts we can expect by the year 2100 include:

Hot on the heels of South Africa's scoring $3.75 billion for a gigantic new coal fired power plant, the country has announced that it's going to use a portion of that power to desalinate seawater.

Desalination is extremely energy intensive and has nasty consequences for the environment.

In other words, in response to a water crisis deriving from global warming and accelerating desertification, and on top of an energy crisis that hardly leaves them enough spare power to carry out this desalination, South Africa is going to burn coal to warm the earth even more.

Last Friday, in a move that surprised no one, the World Bank approved a $3.75 billion loan to South Africa for a coal fired power plant that will spew 25 million tons of carbon dioxide into the atmosphere per year. In one fell swoop, that's equivalent to adding more than two million SUVs to the world fleet.

Defenders of the plant argued that South Africa, which had rolling blackouts in 2008, desperately needs the new plant to allow continued economic growth and to alleviate poverty. There's a lot going on here to distract an observer from the real issue, including politics — the president of the World Bank is a neoconservative appointed by the Bush administration.