Live Earth: Of Pledges and Wedges

by John Osborn

[Note to readers: Ever the editor, I have taken the liberty of updating this blog and tightening its arguments since first posting it last weekend. -- John Osborn]

If you were among those who attended one of the seven Live Earth concerts held around the world on 7/7/07, or tuned in via MSN or NBC, you were asked to commit yourself to six steps, the last of which entailed adding your name to a seven point "Live Earth pledge", making for a total of thirteen environmentally friendly acts. Of these, according to event organizer Al Gore in a pre-show interview, the first of the Live Earth pledges is by far the most important. It reads:

"[I pledge] to demand that my country join an international treaty within the next two years that cuts global warming pollution by 90% in developed countries and by more than half worldwide in time for the next generation to inherit a healthy earth."

By Sunday afternoon, July 8, when I wrote this this entry, roughly 163,000 souls worldwide had signed up, yet I'd wager that few even remotely understand what is being asked. Which pollutants are we talking about, for example, and why is a fifty percent worldwide reduction the right number? What do we mean by "in time for the next generation?" And are the seven actions on the list sufficient (the first clearly is not) or merely representative?

Answering these reasonable questions -- something I could not have done a week ago -- requires a quick tour of current climate science and a look at a useful tool -- "stability wedges" -- devised by two Princeton scientists at the Carbon Mitigation Institute. And a good place to start is with "Field Notes from a Catastrophe", an exemplary 200-page piece of reporting and science writing by New Yorker staff writer Elizabeth Kolbert, which I read on two steamy New England afternoons over the July Fourth weekend.

If you supplement Field Notes with two or three of the scientific papers and essays she cites as well as the three recent working group reports of the U.N. Intergovernmental Panel on Climate Change (IPCC), you'll know as much as any informed citizen can be expected to know about the science behind the Live Earth pledges, and can decide for yourself whether you wish to sign on. In the meantime, here's a summary of what I learned.

Carbon dioxide is the primary engine of global warming

First, to the question of "pollution." The key villain in our climate crisis --whether you believe it's here or in the future -- is carbon dioxide. That's the gas that climate scientists and policy-makers typically single out for their greatest attention, though methane, nitrous oxide and soot also play important roles and will have to be dealt with. Reducing carbon dioxide is a good place to start. Here's why.

Average carbon dioxide concentration in our atmosphere reached 378 parts per million (ppm) in 2005, well above the 299 ppm reached 350,000 years ago, , according to paleontologists, and last equaled 3.5 million years ago. Some scientists believe that carbon dioxide concentrations haven't been this high since the Eocene period, fifty million years ago, when, as Kolbert puts it, "crocodiles roamed Colorado and sea levels were nearly three hundred feet higher than they are today." And of course, because we continue to pour more of the gas into the atmosphere, concentrations will continue to rise through the end of century, with various models predicting levels of 549, 717, 856 and even 970 ppm by 2100.

High concentrations of carbon dioxide are of concern because the gas traps heat, and plays a leading role in driving global warming. There seems to be broad agreement that temperatures today are on average a half-degree higher than they were at the start of the 20th century (1900) and that the many observable changes to our natural environment and climate, which we're hearing more and more about on the nightly news, are due to that seemingly small increase. The half degree rise in temperature has closely followed the explosive rise in carbon dioxide. Even if we were to somehow stabilize carbon dioxide concentration at 450, 500 or 550 ppm, average temperatures are still likely -- according to the IPCC and nearly everyone else -- to rise another degree or two by 2100, if not more. No one really knows what the consequences are likely to be, whether some gotcha -- or as climate scientists call it, a "disastrous anthropogenic interference (DAI)" -- lies in wait, such as the melting of the Greenland ice sheet or a dramatic slowing down of the circulation responsible for the Gulf Stream.

How much carbon dioxide is too much?

Many scientists seem to have settled on 500 (+/-50) ppm as an objective point of danger for carbon dioxide concentration. Five hundred ppm is roughly double that of preindustrial levels, though, as Kolbert points out, "this figure has at least as much to do with what appears to be socially feasible as with what has been scientifically demonstrated." Some scientists think 450 ppm is a threshold, while others argue that it's likely to be 400 ppm or lower. An influential paper by James Hansen of NASA says 475 ppm may be too much. The truth is that no one really knows.

Cutting current carbon dioxide concentration in half over a generation (say twenty years), if that's what the Live Earth organizers are proposing, would be a challenge, to put it mildly. Carbon dioxide in the atmosphere lasts for roughly 100 years, so to cut the current concentrations in half anytime in the next century would mean stopping all man-made carbon dioxide emissions today, tantamount to shutting down the world economy. Even stabilizing carbon dioxide concentrations within a generation at 500 ppm -- the consensus danger point -- looks beyond reach, unless, as two Princeton scientists, Robert Socolow and Stephen Pacala, wrote in an influential 2004 paper, we find a way to hold constant the number of tons of carbon dioxide we add to the atmosphere annually.

Mankind is adding roughly 7 gigatons (7 billion tons or 7 Gt) of carbon dioxide to the atmosphere per year (7 GtC/yr), and under Socolow and Pacala's 2004 "business as usual (BUA)" scenario, that amount will grow to 14 GtC/yr (or more) by 2054. To stabilize carbon dioxide concentrations at 500 ppm over that period of time, they wrote, we need to find ways to run our world without letting our output of carbon dioxide rise any further. Can it be done?

Socolow and Pacala say yes. But the problem is huge. How can the world economy continue to operate (and grow in places like India and China) without adding more and more gas to the atmosphere. Socolow and Pacala proposed breaking the problem into segments, or "wedges". What we need they wrote, are at least seven major initiatives, each of which is capable of preventing one billion tons of new carbon output from being emitted by 2054. Here's a visualization of the problem and its solution.


In fact, Socolow and Pacala managed to come up with 15 initiatives -- "wedges" -- each capable of keeping one gigaton of carbon dioxide out of the atmosphere over the next 50 years and each possible with current technologies. Among the wedges they proposed were a doubling of nuclear power capacity, the mandating of carbon capture and storage for all new coal burning plants, exchanging biomass fuel for fossil fuel, reduced use of vehicles, and so on. The numbers involved are huge, and the U.S. and China, in particular, will have to be on board for most of the initiatives to work. For that reason, the Live Earth organizers suggestion that 90% of the reduction in climate changing pollution needs to come from the developed countries of the world is probably not correct. Each "wedge" needs its own analysis and plan of action, and for any one option, a developed region may or may not have the greatest role to play.

Pick a wedge, one for now another for later; we'll need more than one

For more details, take a look at the list of fifteen wedges posted at the Princeton-based Carbon Mitigation Institute (CMI) website. You'll find that several shed light on one or more of the seven Live Earth pledges. For example, there's Live Earth Pledge #6: plant new trees and join with others in preserving and protecting forests. Socolow and Pacala propose that one-half wedge can be created by reducing the clear cutting of tropical forests over fifty years to zero and another one-half wedge added by planting 741 million acres of new trees (I'll leave it as an exercise to figure how many states that's equivalent to). Clearly the numbers required are huge, well beyond anything attempted to date.

Or take Live Earth Pledge #4: work for a dramatic increase in the energy efficiency of, among other things, our means of transportation. Socolow and Pacala create one wedge by increasing the fuel efficiency of the two billion cars they expect to be in use by 2054 from 30 mpg to 60 mpg. They can create a second wedge if everyone in the world drives on average 5,000 miles per year instead of a predicted 10,000 miles per year. But wait, are we even at a fleet average of 30 mpg? Watching the current struggle in Congress over fuel efficiency standards for U.S. automakers does not raise one's confidence. And the increased miles U.S. commuters are driving -- in he country with the most cars -- makes the second wedge look equally daunting.

So, it's conceivable that seven wedges aren't enough. What if, for all sorts of reasons, some are unable to deliver their one GtC/year of carbon dioxide savings or are simply beyond the will of our institutions? What if carbon dioxide output rises faster than the currently projected rate? At least we have 15 wedges to choose from. But Martin Hoffert, an emeritus NYU physics professor, argues that we'll need more to get to where we need to be. In a much discussed 2002 report that preceded the helpful notion of "wedges", Hoffert advocated for research and investment in a number of futuristic technologies that have the potential to provide us with additional options for the second half of this century, when we may need them desperately. Unlike the CMI wedges, those on Hoffert's list are carbon free. They include fusion, space-based solar power, wind turbines suspended in the jet stream, a Buckminster Fulleresque world-uniting power grid and much more.

Taking the pledge

Such thinking takes us a long way from the Live Earth pledges, but also suggests how big the problem is and how enormous the scale of solutions required.. We're the ones who are going to have to start the work and pay for it. Sacrifices lie ahead, even if we can't fully predict yet what they'll be or who will have to bear them. Sure we can kick them down the road, but then we'll be leaving our children and grandchildren with an even bigger problem. The next generation could find itself dealing with carbon dioxide concentrations of 600, 650 or 700 ppm and mitigation will seem even more impossible.

At least the science now provides us with numbers that we can use to create a kind of global dashboard. On the one-hand, 500 ppm seems like a number we don't want to exceed if we're to limit the amount of warming that occurs over the next hundred years to one degree Celsius or so and if we're to avoid potential DAI events whose triggers are seemingly unknowable until they occur. On the other hand, the notion that we can approach the problem in terms of a series of "stabilization wedges" -- some for now, others for later -- gives us a tool we can use to create solutions of appropriate size (and seriousness) and to measure progress.

Will we do it? There's no evidence we will. At present there are few incentives to implement any of the wedges that have been proposed. No carbon taxes, no carbon caps, no worldwide treaty, no strong signals from the marketplace. So it can't hurt to take the Live Earth pledge, but we need to understand what we're signing up for. If we're agreeing to fight for a 90% decrease in our own production of carbon dioxide, or even a 50% decrease in worldwide growth (7 GtC/yr versus 14 GtC/yr), then we need to be prepared for changes that will be a lot less fun than a rock concert.

In her book, Kolbert lists a number of natural feedback loops that threaten to amplify the environmental changes already underway, in the absence of collective action. But, she concludes:

"Perhaps the most unpredicatable feedback of all is the human one. With six billion people on the the planet, the risks are everywhere apparent. A disruption in monsoon patterns, a shift in ocean current, a major drought -- any one of these could easily produce streams of refugees numbering in the millions. As the effects of global warming become more and more difficult to ignore, will we react be finally fashioning a global response? Or will we retreat into ever narrower and more destructive forms of self-interest? It may seem impossible to imagine that a technologically advanced society could, in essence, choose to destroy itself, but that is what we are now in the process of doing."


M. David Peterson
2007-07-08 22:55:05
Thanks for this, John! Just committed my name to the list...
Keith Breinholt
2007-07-10 08:08:24
I think it wonderful that people are interested in the environment but there are missing facts that people should really consider before devoting their lifes and fortunes to a wedge of C02.

First, all CO2 produced by humans constitues three to five percent (3-5%) of the total world production of CO2. Even if we cut all human production in half we only cut the global production of CO2 by 1.5 to 2.5 percent.

Second, the number one producers of CO2 are organisms in the ocean. The number two producers of CO2 are organisms in the soil.

Third, the rise in CO2 follows the rise in temperature, not precedes it. The revelation here is that more CO2 is produced as temperatures rise because as the oceans and earth warms the organisms in the soil and oceans does their output of CO2.

There are more biological organisms that produce CO2 than humans on earth...and we are a miniscule contribution to the overall production.

Fourth, CO2 is actually a minor greenhouse gas when compared to other gases such as methane. Methane is more of a contributor to the greenhouse effect than CO2 by between one and two orders of magnitude.

Again, the number one producers of methane are organisms that live in the ocean and soil. The number two producer of methane are trees. They produce the organic matter on which all those organisms in the soil live and on which we depend for life.

Unless you want to sterilize the oceans and soil the production of CO2 and other greenhouse gases will continue to rise with the temperature.

So what is the missing piece of information here?

Consider that 30 years ago scientists were predicting a global ice age because temperatures had been falling for nearly 30 years. Looking back we now see that this was an overreaction because it was a normal low in a cycle of temperature variation that has existed long before man came to this planet.

The upshot to this is that CO2 production will also fall as the earths temperature falls with the same 30-40 year cycle of the sun and earth. If you doubt this fact search the web for the terms Atlantic Multi-decadal Oscillation (AMO), Pacific Decadal Oscillation (PDO or El Nino/La Nina), Arctic Oscillation, etc.

We are at the peek of a normal pattern in earths ecology and it is absurd the people have become so histerical while living through their portion of the earth and sun's changing climates.

Why should government dedicate billions of dollars to change something that will change without our intervention? Because there are people who have setup corportions to make huge profits from this histeria and they have influence in government to push their personal agenda to grow their wealth. (Al Gore to name one.)


Keith L. Breinholt

M. David Peterson
2007-07-10 11:01:02

Answer me this: Would it be a bad thing for us, as a human population, to consume less, use more efficient products, reduce our dependence on oil, and overall reduce our footprint on this planet?

There's more to the ingredients the collectively form global warming than *just* the debate on global warming. For example, pollution. Would it be a bad thing for us to reduce our pollution output and clean the air we breathe as a result?

I agree: There are a lot of factors out there that suggest that global warming in and of itself has a lot more to do with issues that are outside of our control. But there are also a lot of factors that suggest that we need to be doing more than we are, and not just to reverse the effects of global warming, but to clean up our planet and, as a result, make it livable for generations to come.

Or do you believe that pollution is "yet another attempt by corporations to *scare* us into paying them more money"?

2007-07-12 11:49:36
Keith, the key issue of CO2 production is not that anthropogenic sources are the primary source of emissions (they aren't) but that the nonanthropogenic sources have been historically highly stable, while our contributions are not. This is similar to the consensus view of the "lagging CO2 levels" issue: a small perturbation in CO2 levels (or other forcing) stimulates a temperature increase, which in turn stimulates increased CO2 emissions, which stimulates an even larger temperature increase ... and so on (at least until hypothesized homeostatic mechanisms kick in and start an ice age. Speaking of ice ages, don't mistake a Newsweek article from the '70s on "global cooling" for scientific consensus. Global warming theory started with Arrhenius). Because Earth exists near the edge of the solar system's habitable zone, small changes in atmospheric greenhouse gases can create large changes in retained temperature.

Atmospheric CO2 levels have historically remained within the 270-290 ppmv range, with ice core samples showing short-lived spikes (possibly up to 315 ppmv) several thousand years ago. However, over the past 200 years of industrialization, atmospheric CO2 levels have reached 367 ppmv and continue to grow. In other words, human sources of CO2 don't have to be the largest contributor to tip the entire system over.

IPCC and US government figures show that an estimated 71% of methane emissions are from human sources (including agriculture and animal husbandry). In the US, most of the methane emissions come from landfill decomposition, natural gas production and use, and animal husbandry, respectively; globally, natural gas, animal husbandry and rice cultivation are the primary culprits. Over the past 200 years, atmospheric methane levels have skyrocketed from 650 ppbv to 1800 ppbv and continue to rise. As global warming continues, we may see an increase in methane releases from oceanic clathrates (though the rate of release is highly uncertain).

As for the Atlantic Multidecadal Oscillation and other temperature signals, these are derived after removing linear temperature changes. In other words, global warming is factored out of the data before the analysis begins. (Without removing the rise, then they tend to both exaggerate and minimize the warming trend.) Are they interesting? Yes. Do they have effects on the global warming trend? Yes. Are they the cause of the warming trend? Mais non!

Let me finish by saying that the underlying model of global warming is not meteorology: it's physics. Unless you know of some exception to the laws of molecular energy absorption and emission, we have to deal with their atmospheric effects. Or, to put it another way, there's only two laws when you're gambling against nature:

1. You can't win;

2. You can't break even.

Keith Breinholt
2007-10-05 14:28:30
David, no one is arguing that we shouldn't help cleanup the environment. If you google my name you will find that I have spent a significant amount of my time doing just that in my own community and other areas in which I can have a direct impact.

The argument that I presented is this. Evaluate what and where we target our effort because our resources are limited and what is being hyped may not have the impact intended.

For instance, there is a way to have a huge impact on the U.S. output of CO2 and at the same time cut our dependency on oil. Can you think of a technology that would help us in this venue? Kill two birds with one stone so to speak? The answer is to replace oil and coal burning electric generation facilities with nuclear power plants.

If we can replace oil and coal power plants with nuclear plants we can then begin to replace gas powered vehicles with plug-in vehicles. Without that change we only change the location at which we burn the oil (and even worse, coal).

Solar cells would need to increase output by several orders of magnitude to be able to replace power plants.

tWb, you make several claims that just don't hold water. You dismissed PMO, AMO, PDO and El Nino/ La Nina by saying that linear temperature changes were factored out. Uh, no.

The observation and calculation of these Oscillations predate the GW debate all the way back to and before the time when some scientists were talking about the coming Global Ice Age. (1970s) Which just happened to be the trough of the Oscillations. So to say that there has been a linear increase is to ignore spikes and oscillations in both directions...which most of the current GW hype does ignore.

Also, tWb, your figures on previous CO2 spikes are off by almost an order of magnitude. The number you are looking for in the Eocene era is 1295 ppm which is three almost four times current highs...and that's long before HUVs, coal power plants and land fills. Current guestimates are that volcanoes producing methane were the main culprits with the CO2 spike following the increased warming trend and increase in bio-organisms.

We don't need to find a new physics. The physics we have is just fine thank you...unless we get excited about GW hysteria and let reason disappear into feel good efforts that burn money and time without EFFECTIVELY addressing real issues.

Hydrogen powered cars are not a solution, the cheapest source of hydrogen is made from...oil. The only renewable source of hydrogen is from electic hydrolysis, and electricity in the U.S. is mostly generated from coal, oil and gas burning power plants.

If we paved the entire United States with solar cells we would generate an estimated 4-6% of our energy needs: solar cells help but they are not a complete solution...they would need to increased efficiency by several orders of magnitude...which is not reasonable since energy conversion for commercial solar cells is 20%. One order of magnitude increase would mean solar cells collect 200% of the solar energy that falls on them. Solar cells help but we need other clean sources as well.

Biofuels take almost as much energy to create as they actually produce in work...and that doesn't factor in the quadrupling of CO2 pollution that is created because we have to almost quadruple the energy burned to create an equal amount of work energy. Biofuels are just an expensive form of farm subsidies and should be abandoned unless we can create at least double the amount of energy used in production.

Wind energy is subject to long spells of 'good' weather where no power is generated.

Hydro power and nuclear power are the only relatively clean energy alternatives that can meet our growing energy needs and relieve our dependency on oil.

Given the fact that we mostly know how to reprocess spent nuclear fuel and our ability to do so increases with each year, nulcear power looks like our best option to reduce CO2, reduce oil dependency and supply our energy needs.


Keith Breinholt