More on Carbon Isotopes

Here are two charts that take the C14 story back in time. You can see how the C14 ratio was declining from the early 1800s, then shot up as nuclear tests added C14 to the atmosphere. When the tests ended in the 1960s, C14 started to decline again. This is dispositive evidence that the extra CO2 has come from fossil fuels.


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Are Humans Causing Global Warming? Ask Floyd Landis.

Blog Post for Columbia University Press

The earth is warming. But can we be sure that humans are the cause? Yes. The same way cycling officials were sure that biker Floyd Landis doped with synthetic testosterone while winning the 2006 Tour de France.

With Lance Armstrong retired and most of the other top riders expelled for illegal drug use, Landis had become one of the favorites. He was leading when in stage 16 he fell to eleventh place. Then, just as his chances of winning seemed dashed, Landis won the next stage going away and went on to ride the Champs-Élysées in the winner’s yellow jersey.

A few days later, Landis’s team announced he had failed a test for banned steroids. Landis appealed the ban, raised an estimated $1M for his defense, and wrote a 300-page book titled, “Positively False: the Real Story of how I won the Tour de France.”

After years of denial, in 2010 Landis reversed himself and admitted that from 2002 through 2006 he had used a grab-bag of banned substances and methods. Why did he finally have to give up his denial? Because the carbon isotope test proved beyond reasonable doubt that he had doped with synthetic testosterone.

Testosterone is mostly carbon. Synthetic testosterone is made entirely from plants, which have a different carbon isotope ratio than our environment overall. The carbon in Landis’s body had the distinctive plant ratio, proving beyond reasonable doubt that he had doped with synthetic testosterone.

So how do scientists use the method to confirm that humans are causing global warming?

Since 1800, CO2 in the earth’s atmosphere has risen 40% and because of the greenhouse effect, warmed the planet. The obvious source of the added carbon is the 330 billion tons of carbon that burning fossil fuels has added to the atmosphere since the Industrial Revolution. Yet global warming deniers deny this obvious fact. Well then, let’s prove it.

First, coal, oil, and natural gas also come from plants and also have the distinctive carbon isotope ratio of plants. As CO2 in the atmosphere has built up steadily, its isotopic composition has shifted just as steadily in the direction of plant carbon. That tells us the added carbon is coming from plants. But what kind of plants? That question we can also answer.

One carbon isotope, C14, is radioactive and dies away to undetectable levels in 50,000 years or so. Fossil fuels, being millions of years old, have no C14 left. Adding ancient carbon should have lowered the proportion of C14 in the atmosphere—and it has. For the last 50 years, as the amount of carbon in the atmosphere has increased, its C14 ratio has fallen steadily.

Just as the carbon isotopes prove that Landis doped his body, they prove beyond reasonable doubt that humans are doping the atmosphere with ancient plant carbon, carbon from fossil fuels.

Unlike people, isotopes do not lie.

Eggs Cause Chickens to Hatch

Letter in the Santa Barbara News Press, January 24, 2012

A letter from Goleta is titled, “Get ready for the coming ice age.” But there’s no need to rush—the next ice age is at least 20,000 years in the future. If we continue to add CO2 to the atmosphere, the ice is even farther away. Let’s correct some of the letter’s other myths.

“Temperature changes cause CO2 changes.” That’s like saying, "Eggs cause chickens to hatch.” Changes in the earth’s orbit and axial tilt started the warming that ended the last Ice Age. But once started, CO2 amplified the warming. It has to: it’s a fact of physics that more CO2 means higher temperatures.

“Humans cause only 3% of CO2 emissions.” True, but misleading. Before we started burning fossil fuels, the amount of CO2 emitted and the amount absorbed by the oceans and plants were in balance. Beginning about 1800, we began to upset that natural balance and since then CO2 levels have risen by 40% and temperatures by about 1.4°F.

“In 1975, Newsweek said the almost unanimous view of climatologists was that the cooling trend would result in famines that could be catastrophic.” Scientists actually said something quite different. From 1965-1979 they published 68 studies on future global temperatures. Only 10% of them predicted oncoming cooling. Today the percentage is too low to count.

Finally, the writer assures us that this “brief period of warming” will be followed by “an abrupt plunge in temperature.” Will you stake your grandchildren’s future on that blind assertion?

A Day of Darkness

April 22, 2012. Earth Day: A day of darkness to prevent an age of darkness.

Washington DC – Thousands of Internet sites are taking part in a “blackout” to protest the lack of government action to prevent dangerous global warming. The most prominent social networking and communication sites went down for 24 hours starting at midnight last night, showing a dark homepage and directing users to the protest movement's central site.

Included were Facebook, Google, Twitter, Wikipedia and WordPress, which urged the owners of the 72 million sites that use its service to join. Wikipedia founder Jimmy Wales said, “A few months ago we went dark to protest legislation that the U.S. Congress was considering that would fatally damage the free and open Internet.” He continued, “But something much more important than the Internet is at stake: the future of humanity.” Twitter CEO Dick Costelo said, "We declined to join the earlier protest because we thought it was foolish to close a global business in reaction to single-issue national politics. But global warming threatens all businesses and all peoples.” He summed up, “Twitter is in."

By the end of the day, President Barack Obama, surrounded by the senior members of his party and a surprising number of Republicans, told the press that, “Our society cannot function without the Internet and it cannot function for long with global warming. It is time for reason and scientific knowledge to direct congressional action to curb carbon emissions and put the world on track to limit global temperature rises to 2°C.” The president went on, “Everyone who has children and grandchildren should demand that their elected representatives act and act now.”

Many dark US sites urged visitors to call their Congressional Representative, most providing the name and number. went further by offering to call a visitor, provide talking points, and connect the visitor with his or her member of Congress.

Congressional telephone lines and e-mail servers were jammed as millions joined the protest. Following President Obama’s press conference, Republican Leaders Mitch McConnell (R-KY) and John Boehner (R-OH) jointly pledged to take up action to curb carbon emissions as their highest priority.  

The protest site asked each member of Congress to take the following pledge: “I accept the findings of the US Academy of Sciences that ‘Climate change is occurring, is caused largely by human activities, and poses significant risks for a broad range of human and natural systems.’” By the end of the day, every Democrat and many Republicans had signed the pledge and the number was growing hourly.

Many university sites joined in the blackout, including MIT, Oxford, Stanford, and the University of Queensland. Scientific journals including Science Magazine and Nature also went dark. Shutting down for the day were the British House of Commons and the German Bundestag.

Many climate blogs joined, including,, and    

Noted climate scientist James Hansen, who has been arrested for joining protests against carbon polluters, said, “This may be humanity’s last chance.”  

Response to another letter in the Santa Barbara News Press

Letters: Arguments against the hoax theory

Dr. James L. Powell Buellton

December 7, 2011 5:28 AM

A letter writer from Goleta thinks "man-made global warming is a hoax." The evidence? "Hidden e-mails from the unethical Intergovernmental Panel on Climate Change showing how [scientists] have have cherry-picked their data ... and hidden data that ... contradict them." Not so.

First, there have been nine independent investigations of the so-called Climategate e-mails (stolen from a UK university, not the IPCC) and each has found that no data were manipulated or hidden -- there was no wrong-doing.

Second, if global warming is a hoax, then it must be possible to organize scientists from around the world into a global conspiracy. No one who has ever attended a faculty meeting could believe that.

Third, if global warming is a hoax, then why was the first decade of this century the warmest on record? Why are twice as many high-temperature records being set as low-temperature records? Why is spring starting earlier and fall later? Why are glaciers, Arctic sea ice, Greenland and Antarctica melting at unprecedented rates? Why is sea level rising faster than any time in history? Why is the world experiencing more extreme weather events? Why are animals and plants migrating toward cooler climes?

Global warming is real, but is it our fault? Yes. The same carbon isotope fingerprint that nailed cyclist Floyd Landis shows that the extra CO2 in the atmosphere came from burning fossil fuels.

Response to letter in the Santa Barbara News Press

To the Editor:
“Why should we believe temperatures aren’t still rising and falling as they have naturally in the past? Has something changed….?” The News Press recently singled out these questions from a letter writer as “Choice Words.”
Well yes, something has changed. Since the Industrial Revolution 200 years ago, humans have burned huge amounts of coal and oil, increasing the CO2 concentration in the atmosphere by 40 percent. The greenhouse effect, a fact of physics, means that the more CO2 we add to the atmosphere, the higher the temperature at the surface. Scientists have proved that the extra CO2 came from fossil fuels, not from some natural source.
As fossil fuel combustion and atmospheric CO2 have risen, so has temperature. 2010 had the highest temperature on record. Since 1970, each decade has been hotter than the last. In the last 12 months, US record high temperatures have outnumbered record lows by nearly 11:1. Next week, Minneapolis is forecast to hit 116°F!
Ice caps on Greenland and Antarctica are shrinking, Arctic sea ice is declining, glaciers are melting, sea level is rising, species are migrating, spring is coming earlier and departing later, and so on. And the weather has turned weird--or has the climate itself started to change? Meteorologist Dr. Jeff Masters estimates that 2010 had the most extreme weather since at least 1816, when a huge volcano blew up.
These facts are why 100 national and international scientific organizations say that global warming is real, caused by humans, and dangerous. Not a single scientific organization in the world denies global warming. Ninety-seven precent of climate scientists accept human-caused global warming.
We can either trust scientists or put our children and grandchildren at risk.

What is Global Warming?

Without the gases in the earth’s atmosphere, the average temperature at the surface would be nearly 60°F colder and human civilization could not exist. Our planet would more closely resemble Mars, which barely has an atmosphere and whose temperature as a result varies from lows of about −125°F during the polar winters to highs of up to +23°F in summer.

Scientists have known since the 1820s that gases in the earth’s atmosphere trap heat and reradiate it down to the surface, warming the globe enough to allow us to live here. In the 1860s, scientist John Tyndall discovered which gases do most of the absorbing: water vapor and carbon dioxide. These gases allow the sun’s rays to pass through to the earth’s surface nearly unimpeded, but then absorb the escaping heat waves and re-radiate their energy back down. We call this the greenhouse effect, a useful shorthand but actually a misnomer because in a greenhouse, the glass simply blocks the heat waves from escaping rather than interacting with them.

That atmospheric gases warm the surface of the earth is a fact of physics. The more CO2 in the atmosphere, the warmer the earth. In the next post, I will address the obvious question of how much warming a given amount of extra CO2 might cause. In the post after that, how we know that human emissions of CO2 have caused the observed global warming.
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