Global Warming: The Era Of Fossil Fuel Energy Is Ending
by Steven H Johnson, Principal, Wallcharts Workshop Inc

Current debates over Global warming bring to mind an ocean liner staying on course while its crew speculates on the significance of the iceberg that's dead ahead. Yet, despite the apparent confusion, the core issue is as not all that complex. It boils down to the fact that while we don't know the exact number with certainty, there's a safety limit to atmospheric CO₂. Exceed that limit and climate disasters multiply. Climate safety demands that atmospheric CO₂ be capped at the lowest possible total.

Conceptually, it doesn't matter what the safety limit is -- the action implications are much the same. Every plausible scenario for assuring safe levels of global CO₂ requires net annual emissions of carbon dioxide to go to zero. If the higher limit scenario is valid, we may have a few years of lead time remaining. If lower, our lead time is all used up. Going to zero on net carbon dioxide emissions ends up being the only safe answer under all scenarios.

That's the central thesis: let's back up, review the basics, and build the case step-by-step.

We start with heat balance. Over the long run, the Earth maintains its average temperature by radiating away into space all the heat it receives from the sun. Our planet's average temperature, however, is affected by the presence of greenhouse gases -- water vapor, clouds, carbon dioxide, methane, and a number of others. If greenhouse gases didn't exist, the planet's average temperature would stabilize at -20°C. At historic concentrations of CO₂, the Earth's average temperature stabilizes at +13°C. (Carl Sagan, Billions and Billions, pp 102 - 103.)

What happens to the earth's heat balance, though, when new greenhouse gases are added to the atmosphere? Heat balance rises and, in time, stabilizes at a new and higher temperature level.

The question of how greenhouse gases affect the planet's thermal regime is a question of utmost importance. CO₂ is a very persistent greenhouse gas -- because it's so non-reactive, scientists say it remains part of the atmosphere for centuries. Every ton of coal and gallon of gas add irreversibly to the world's total.

A few scientists anticipated this problem more than fifty years ago. As an important first step, in 1958, they established the world's first CO₂ observatory putting it on Mauna Loa, Hawaii, to be as far removed from industrial sources of CO₂ as possible. The measurements they've taken regularly since 1958 give an excellent picture of the global average.

CO₂ is not a major atmospheric gas -- at least not during this geological era. When Mauna Loa scientists measure its concentration in the atmosphere, they report their results in ppm. Mother Nature's pre-industrial norm, 280ppm, is another way of saying that carbon dioxide used to make up slightly less than three one-hundredths of one percent of the total atmosphere. Today's measurement: 380ppm, and climbing.

Like many others I have difficulty relating to measurements that are expressed in ppm. I would rather deal with, say, the tons of CO₂ output from my car and my house each year, or the billions of tons of CO₂ present in the atmosphere.

My first questions -- once I started doing some digging on global warming -- were tonnage questions:

• How many tons of CO₂ are in the atmosphere now?
• How rapidly is atmospheric tonnage growing?
• How does that compare with emission tonnage?

According to Wikipedia, the world's atmosphere weighs 5.15 quadrillion tonnes (tonnes = 1000 kg = 2204.6 lb). One one-millionth therefore weighs 5.15 billion tonnes. In e-mail correspondence with scientists, who track these matters for a living, I have learned that one part per million of carbon dioxide -- a heavier gas than oxygen or nitrogen -- weighs approximately 7.77 billion tonnes.

Here's the trend, stated in billions of tonnes. The pre-industrial norm for atmospheric CO₂ is 2175 billion tonnes. Atmospheric CO₂ weighs in today at 2955 billion tonnes, a 36% increase above Mother Nature's norm. The total stock is growing by 140 to 150 billion tonnes per decade. It's important to note that this growth rate has accelerated enormously over the past four decades.

In the early 1960s, the growth rate of atmospheric CO₂ averaged 5.5 billion tonnes per year. By the late 1980s, the growth rate had shot up to 13.2 billion tonnes per year, two and a half times faster. Total global emissions of CO₂ are somewhat higher. The world's oceans absorb about two-fifths of any new CO₂; the remaining three-fifths end up in the atmosphere.

There's an interesting anomaly in the early 1990s. The June 1991 eruption of Mount Pinatubo in the Philippines discharged an enormous amount of sulfur into the atmosphere. Sulfur aerosols softened sunlight and stimulated photosynthesis for more than two years afterwards, with an impact significant enough to show up in global CO₂ measurements. (Scientific American, March 28, 2003)

Now, in 2006, we're seeing a CO₂ growth rate of 140 to 150 billion tons per decade. The Kyoto Protocol calls for annual emissions to be reduced, and sets a target 9% below the 1990 average. As the chart above shows, Kyoto targets imply atmospheric CO₂ growing at 125 billion tonnes per decade instead of 145, an almost inconsequential reduction.

As if this weren't alarming enough, the picture becomes even more serious when methane and other greenhouse gases are taken into account. According to NOAA's Climate Monitoring and Diagnostics Laboratory, total radiative forcing -- the additional solar energy the Earth receives from human-caused greenhouse gases -- is up more than 20% since 1990. A 20% rise in only sixteen years!

Given the above the central question that faces the world is simple: and stark. Do we think it safe for atmospheric CO₂, a greenhouse gas, to rise steadily and without limit? If limitless growth isn't safe, how dangerous is it? (A similar question can be asked of methane and other greenhouse gases.)

I will leave it to ardent risk-seekers to defend the proposition that a limitless increase in CO₂ is nothing to worry about. For the rest of us, civic prudence dictates a different conclusion. Rising tonnages of CO₂ eventually become so risky that setting an upper limit is essential for the planet's well-being.

Keep in mind that we're dealing with a long-fuse issue here, because greenhouse gas operates with long lead times. Carbon dioxide warms the climate by first warming the oceans and the land. Each increase in atmospheric CO₂ raises greenhouse potency. The world's oceans don't adjust instantly -- it takes several decades for them to absorb the full warming effect.

In other words, the global warming we're already seeing isn't the result of today's CO₂ levels-- 2955 billion tonnes -- but the result of somewhat lower tonnages that were present sixty years ago, forty years ago, twenty years ago.

Also keep in mind that polar regions are more sensitive to rising carbon dioxide levels than tropical regions. Water vapor and clouds are the dominant greenhouse gases in the tropics, while CO₂ represents at best 10% to 15% of the total greenhouse effect. Higher levels of atmospheric CO₂ aren't so noticeable in the tropics.

The greenhouse gas situation is different in polar regions, where the air is cold and dry, where water vapor's greenhouse role is much weaker, and carbon dioxide's greenhouse role correspondingly stronger.

Scientists who track polar climate variables report substantial changes. Shrinking polar ice cap. Polar bears in decline. Alaska's Bering Strait islands losing their protective shield of sea ice. Summer melting rates on the Greenland ice sheet up markedly in the past two decades.

Those who follow these issues closely have begun to wonder: what amount of atmospheric CO₂ will it take to cause ice sheets on Greenland and West Antarctica to melt completely?

If we stay with fossil fuels globally, it's a very good bet that we'll learn the answer the hard way. CO₂ levels will rise higher and higher. Thawing permafrost will contribute dangerous concentrations of methane. At some point in the next generation or two, if it hasn't happened already, our atmospheric CO₂ will pass the point of no return, the ice sheets will melt, and scientists will say, "Ah ha, so that's how much CO₂ was needed. Now we know for sure."

Once these two ice sheets melt, calculations show, the oceans of the world will rise by 40 feet or more. Low-lying coastal regions that are presently home to hundreds of millions will be so much underwater real estate. Say good-bye to Bangladesh, The Netherlands, much of Florida, the US Naval Academy, and quite a bit of Annapolis, Maryland, which happens to be my home.

This brings us back to the central question: "Is there a danger zone tonnage for atmospheric CO₂, a global total whose potential climate consequences are so severe we dare not take the risk?"

Jim Hanson, a NASA scientist and one of the leading climate modelers in the world, argues that 450ppm is the point where the safety zone runs out and the danger zone begins. Exceed that level and too many climate triggers get pulled, causing an irreversible cascade of events. If we assume that 1ppm equals 7.77 billion tonnes, the allowable CO₂ maximum is 3500 billion tonnes.

Given today's fossil fuel consumption trends, it won't take us more than three decades to shoot right past the 3500 billion tonnes danger marker.

But what if the trigger tonnage is 500 billion tonnes higher? Or 1000 billion tonnes higher? Or 400 billion tonnes lower? What if we've already passed the safety limit?

No matter which answer is the most accurate, the action implications are the same. No matter what safety limit we pick, if we're not to exceed it, net emissions of CO₂ have to fall to zero. Worldwide. And stay at zero. For centuries to come.

Suppose we pick 4000 billion tons as the end of the safety zone, the beginning of the danger zone. The only way to hold atmospheric CO₂ below that level is to take net emissions of carbon dioxide all the way to zero. Otherwise, it's just a matter of time till total CO₂ rises into the danger zone.

The same reasoning applies to 3500 billion tonnes, or 3200 billion tonnes, or any other number.. To stay within the safety zone, annual emissions have to go to zero. Given the centuries-long persistence of atmospheric CO2, there's really no other option.

Oddly enough, hardly any of America's leading environmental organizations have figured this out. Apparently their leaders haven't taken a very hard look at the math. Instead, groups like the Sierra Club and Environmental Defense promote Kyoto-style emission reduction as their main theme. Drive less. Buy smaller cars. Switch to better light bulbs. Ratify and implement the Kyoto Protocol. These steps modestly delay the inevitable. Instead of shooting past Hanson's danger marker in 2035, say, we shoot past in 2040, or 2045.

If one believes the inconvenient truths that the numbers presented here indicate it would appear that the leaders of the environmental movement went down a blind alley quite a long time ago. Instead of framing humanity's central challenge as executing a shift from dirty technologies to clean technologies, they argued for reduced consumption as the strategy for saving the planet. Since prosperity was thought to depend on dirty technology, only by consuming less would it be possible to save the planet.

At its core, this view is almost pure poppycock. The root issue is dirty technology, not consumer behavior. Energy efficient consumer behavior is a good idea, but by itself it will never keep atmospheric CO2 from escalating to deadlier and deadlier levels. Conversely, clean technology not only saves the planet, it can also support a higher, more abundant standard of living.

So about all that's standing between us and a sane, prosperous future is the global popularity of fossil fuel energy and a lack of will to replace it with something better. It's difficult to see how environmentalists could have overlooked this rather obvious point, but somehow all but a handful of brave souls have carefully ignored this 800-lb gorilla sitting in the middle of our collective living room. Rather than call for as rapid a transition from fossil fuels to renewable energy technologies as is technologically and economically feasible, they ask only for more efficient consumption of fossil fuel. Rather than partner with corporations in a global campaign to leave fossil fuel energy behind, they attack corporations for promoting rising standards of living.

This clash is a waste of everyone's time. A safe and healthy climate is essential to environmentalists and corporate leaders alike.

The transition from fossil to renewable energy sources is quite possible, but it will take some unconventional thinking to make it practical and acceptable to both the general population and the business community. Part of the key to success will be for stakeholders to partner as broadly as possible. Instead of asking individual homeowners to retrofit their homes, we should devise programs that enable neighborhoods to undertake community-wide retrofits that have greater economies of scale. If we're to shift to non-fossil fuel vehicles, we need to develop a national program of moon-shot proportions which evokes cooperation from motorists, service station owners, and auto companies. A safe climate is of equal value to Republicans and Democrats. The more we see ourselves as mutually engaged in a shared patriotic transformation, the more successful we'll be.

Imagine Home Depot and Lowe's devoting a thousand square feet of exhibit space in every store to photovoltaics and geothermal wells and thermal mass construction and small-scale wind generators. Imagine Popular Mechanics and Popular Science talking up earth-friendly energy for every home, business, vehicle, and power plant.

Were every capital budget in this country to be put on a 25 year clean energy timetable, as a nation we'd have the go-to-zero annual emissions challenge pretty much licked by the early 2030s. Once the nation commits to a post-fossil fuel future, experience curve effects will sharply reduce unit costs. Today's somewhat pricey answers will become tomorrow's affordable answers, not only for Americans, but for all the world.

The world's earliest surviving steam engine is said to be on display at the Henry Ford Museum in Dearborn, Michigan. Wouldn't it be something -- in 2040, say -- if America's very last fossil fuel engine were to end up in Dearborn as well? Two bookends to the era of fossil fuel technology. An era that was good for quite a long time, yet also an era that finally had to take its leave.

About The Author

Steven H Johnson has spent some years as a number-crunching management consultant. He presently runs a small non-profit, The Wallcharts Workshop, and is at work on a book, Stewards of the Whole: How to Create a Future That's Not Broken. Steve lives in Annapolis, Maryland, in a house that's only twenty-five feet above sea level. He can be contacted here.

Suggested Readings

Tim Flannery, The Weather Makers: How Man Is Changing the Climate and What It Means for Life on Earth
Elizabeth Kolbert, Field Notes from a Catastrophe: Man, Nature, and Climate Change
James Gustave Speth, Red Sky at Morning: America and the Crisis of the Global Environment
Al Gore, An Inconvenient Truth: The Planetary Emergency of Global Warming and What We Can Do About It

Author's Note:

Once you study the issue closely enough, you'll have little trouble finding the flaws in State of Fear, science fiction author Michael Creighton's rebuttal of global warming. One important example is how Creighton misses the lag time issue, the fact that it takes several decades for higher CO₂ levels to take full effect. Creighton also misses the point that global warming affects polar regions long before it affects temperate and tropical regions. He gets tied up arguing the minutiae of climate modelers and their temperature change predictions, meanwhile overlooking the driving fact that atmospheric CO₂ is now growing at nearly 7% a decade. Nevertheless, I do agree with Creighton's final point -- research funding should be double-blind. Researchers won't be as objective as the nation needs them to be when they know who's footing the bill.