How Much of Atmospheric CO2 Increase is Natural?

August 27th, 2014

I frequently get asked the question, if natural CO2 emissions are about 20 times what anthropogenic emissions are, how do we know that all of the atmospheric CO2 increase is due to human activities?

One answer often given (and the one I often use, too) is that since we emit twice as much as is needed to explain the atmospheric increase, there is no reason to look elsewhere. Just assume the huge natural sources and sinks of CO2 are in balance, and then humans are responsible for the small changes we see.

Natural Variations in CO2 are LARGE
But what if (I’m NOT necessarily advocating this) most of the CO2 humans produce, which is near the land surface, is absorbed by vegetation, and the observed global increase is partly or mostly due to outgassing of the oceans?

Scientists seem to make the assumption that nature is always in balance. But this clearly isn’t the case for natural sources and sinks of CO2 (you can find such plots in the IPCC reports, too):

Fig. 1. Yearly anthropogenic CO2 emissions versus yearly increases in atmospheric CO2.

Fig. 1. Yearly anthropogenic CO2 emissions versus yearly increases in atmospheric CO2.

There are obviously some very large natural yearly imbalances in CO2 sources and sinks, with the atmospheric yearly increase ranging anywhere from 23% to 100% of anthropogenic emissions. If the yearly fluctuation are this large, how do we know that nature is in long-term balance for CO2 sources and sinks? The answer is, we don’t. This is why NASA launched the OCO-2 satellite, to try to get a better handle on the regional sources and sinks of CO2 around the world.

Furthermore, in contradiction to IPCC predictions, the ability of the Earth to absorb extra CO2 seems to be increasing with time: the equivalent of 40% of our emissions were being absorbed early in the record, a fraction which has increased to 50% late in the record.

Given these very large year-to-year variations, is it that unreasonable to hypothesize that there might be a long-term natural imbalance between natural sources and sinks of CO2, which is also contributing to the observed increase?

The trouble carbon budget modelers have with this possibility is that it would require that there are even stronger sinks of anthropogenic CO2 emissions at work, and the IPCC is already having trouble explaining where all of the “extra” CO2 is going.

For example, rather than nature normally being in perfect balance and then absorbing ~50% of our CO2 emissions, nature would have to be absorbing (say) 75% of our emissions but contributing the remainder to the observed atmospheric increase from a natural source elsewhere.

We really don’t know where these sources and sinks are…all we see is the net result of all of them expressed in the average atmospheric concentration. Like your bank balance representing the net effects of all deposits and withdrawals.

Carbon Isotopes
The arguments from carbon isotopes (C13…sorry for the unconventional notation) that fossil fuels are the source of all the atmospheric increase don’t hold water as far as I can tell. As I posted nearly 6 years ago, the C13 fraction in the long-term trends of atmospheric CO2 are not inconsistent with a natural source, after I examined the observed C13 variations at three time scales: seasonal, interannual, and long-term trends:

Fig. 2. C13 fraction variations contained in seasonal versus, interannual versus decadal variability, compared to known geophysical sources.

Fig. 2. C13 fraction variations contained in seasonal versus, interannual versus decadal variability, compared to known geophysical sources.

I believe that pointing this out is part of the reason why Murray Salby got into trouble recently. The scientific community doesn’t take kindly to some of us suggesting nature itself might be causing “carbon pollution”. Baaad scientist.

If I am misunderstanding something about the C13 arguments, someone please let me know, since I’m not an expert in atmospheric chemistry. Ferdinand Engelbeen kindly responded to my post from 2009, and if he would like to provide an updated argument I would be glad to post it here.

A Simple Analysis: Could 40% of the CO2 Increase be Natural?

I downloaded from CDIAC the latest spreadsheet with the yearly global CO2 source and sink estimates, for the period 1959 through 2012. I wanted to address the question: from a statistical point of view, how much of the year-to-year changes in atmospheric CO2 can be explained by different sources and sinks?

The spreadsheet includes yearly estimates of (1) atmospheric increase in CO2, (2) fossil fuel and cement production of CO2, (3) an estimate of the ocean CO2 sink, (4) an estimate of land use change emissions CO2 source, and I added to these variables (5) global land surface temperature [CRUTem4], and (6) global sea surface temperature [HadSST3].

As a first step, if we do simple correlations between the atmospheric CO2 variations with the other variables we find the highest correlation between temperature and CO2, and a little lower correlation with anthropogenic emissions:

Correlations with Yearly Atmospheric CO2 increases (1959-2012)
T_ocean : 0.70
T_land: 0.71
Fossil Fuels: 0.67
Ocean sink: 0.63
Land Use: -0.36

The fact that temperature has a higher correlation with yearly CO2 changes than does the anthropogenic source shows just how strongly the temperature variability affects atmospheric CO2 content.

But correlating data with substantial trends in the data can be deceiving. Strictly speaking, all linear trends are perfectly correlated with each other, even those which have no causal relationship whatsoever between them.

So, we can detrend all of the data, and see what information is contained in the departures from the linear trends. This reduces the correlations substantially, since the variability associated with the trends has been removed:

Correlations with Yearly Atmospheric CO2 variations (1959-2012, detrended)
T_ocean : 0.35
T_land: 0.34
Fossil Fuels: 0.13
Ocean sink: 0.01
Land Use: 0.00

We see that the correlation between atmospheric CO2 and temperature remains the strongest, but the fossil fuel signal is very small, possibly because the detrended variations in anthropogenic emissions are quite small, and so subject to greater errors.

The ocean sink and land use estimates seems to have no correlation with atmospheric variations after detrending, and so were excluded from further analysis.

If we then perform a multiple regression between atmospheric CO2 versus the anthropogenic source and 2 temperature terms (all detrended), and apply the resulting coefficients to the original (not detrended) data, we get the following plot:

Fig. 3. Yearly changes in atmospheric CO2 in observations versus a simple statistical model trained with detrended anthropogenic emissions and temperature data.

Fig. 3. Yearly changes in atmospheric CO2 in observations versus a simple statistical model trained with detrended anthropogenic emissions and temperature data.

At face value, what this plot shows is that the observed increase in atmospheric CO2 can be easily explained (actually, “over-explained”) with a combination of anthropogenic emissions and increasing temperatures, where the quantitative relationships are based upon detrended data. The contributions to the model trend in atmospheric CO2 is 61% anthropogenic, 22% ocean temperature, and 17% land temperature.

The model overshooting of the trend could be due to some unknown carbon sink which isn’t directly related to surface temperature. Or, it could just be an artifact of the poor assumptions inherent in the simple statistical model (e.g. that the interannual relationship between temperature and CO2 applies to long-term trends).


By itself I don’t think this “proves” anything. But it does show that since warm years tend to cause greater natural emissions of CO2 into the atmosphere, we should at least consider the possibility that the long-term warming trend (whatever its cause) is contributing to the increase in atmospheric CO2.

What caused the warming that caused the CO2 increase? Well, as I have been saying for years, chaotic circulation-induced changes in cloud cover can cause global warming or cooling. Or pick some other mechanism. Maybe that big ball of fire in the sky.

My point is, the climate system is not static.

We should remember how much we have anthropomorphized recent warming: Human activities produce CO2 in reasonably well known amounts, humans do the monitoring of CO2, then humans do the modeling. Since we really don’t understand the natural sources and sinks very well — not to the <1% level needed to document that a “natural balance” exists (since human emissions are now close to 5% of natural sources and sinks) -- we just assume they are “in balance”. There, problem solved.

So, we impose a human explanation on what we observe in nature. A common tendency throughout human history. We are searching for answers at night under the only streetlamp where we can see.

UPDATE: I didn’t address the fact that atmospheric O2 concentrations have fallen commensurate with the rise in atmospheric CO2, which is supposedly “proof” of fossil fuel burning being the 100% cause of atmospheric CO2 increase. But increased oxidation of organic matter has the same effect on O2.

Update #2:
Just to clarify…even if all of the atmospheric CO2 increase is manmade, I continue to believe it is more beneficial than harmful.

Technically, Scott Brown is Correct

August 26th, 2014

SbrownofficialGawd, I wish the media were as smart as they think they are.

Scott Brown, Republican candidate running to be a senator from New Hampshire, on Saturday participated in a debate during which he was asked if he believed:

“…the theory of man-made climate change has been scientifically proven”.

Now, first of all, nothing is science is “proven”. If you think it is, you don’t understand science.

Brown’s answer to the question was “no”. And that is correct. There is no way to prove that our addition of 1 molecule of CO2 to each 10,000 molecules of atmosphere over the last 100 years has had any measurable influence (there are no fingerprints of human-caused versus natural warming).

All the usual left-leaning news outlets have been having a cow over this supposed reversal of Brown’s position. The ThinkProgress site entitled their article, “Scott Brown Flips to Full-Blown Climate Denier“.

The “flip” is because Brown had previously (in 2012) said that climate change was “a combination between man-made and natural” in origin.

And that statement, too, is correct. As a climate researcher, I also believe it is some (unknown) combination. But there is no way to “prove” it.

I haven’t been following the race, and so have no opinions on the candidates. I’m just pointing out that Scott Brown’s position is entirely defensible, and the media conveniently hears what they want to hear.

If the media can’t ask a technical question correctly, they shouldn’t ask the question.

Or, don’t ask one question, then assume the resulting answer is to a different question.

The People’s Climate March. Do it for the Kittens!

August 25th, 2014


Crazy Man to Live on Iceberg for 1 Year

August 24th, 2014

I suppose this was inevitable.

An adventurer who has rowed solo across oceans and jogged a total of 4 lightyears is going to bring attention to global warming (what’s that?) by living on a Greenland iceberg for up to a year starting next Spring.

As reported by, Alex Bellini, a “professional adventurer” from Italy, will chronicle the melting of the iceberg (which, of course, never happened in summer before humans began burning fossil fuels).

For those new to how high-quality science works, Mr. Bellini explains in his own words (emphasis mine):

My objective is reporting and investigating, by means of scientific methods, the entire lifetime of an iceberg. I want to prove how the pace of ice-melting has dramatically accelerated over the last decades.

How exactly he is going to do that by sitting on an iceberg as it melts in the summer, which is what icebergs do anyway, remains to be seen.

The sad part is the number of people who will fall for this. Probably including Mr. Bellini himself. Pure publicity stunt, no scientific value whatsoever.

I guarantee you if he does camp out on an iceberg, he will not stay there a year. Greenland winters are brutal.

Censorship Alive and Well at Wikipedia

August 21st, 2014

propaganda-ministryThat didn’t take long. Less than 24 hours after I noted the use of the “97% of scientists agree” meme as an example of “propaganda techniques” on Wikipedia, the example has disappeared.

But “Hope and Change” remains there as an example of Ad Nauseum propaganda. Time to scrub that one, too?

The Global Warming Ice Bucket Challenge

August 20th, 2014

ice-bucket-challengeThis ALS ice bucket challenge thing seems to be very successful in raising money for ALS research.

Or is it raising awareness? I’m not sure. Maybe both.

I think it’s now time to raise awareness of global warming. After all, if we didn’t tell people about it, they would never know, right? We would instead have to actually experience global warming ourselves, rather than measure alleged temperature changes of tenths of a degree over a period of 50 years.

So, you have two choices. Either (1) pour a bucket of ice water over your head, which will require the wasting of the extra energy needed to freeze the water thereby making global warming even worse, or (2) donate $100 to Greenpeace to help make sure millions of poor people can’t avoid blindness or death by having access to Golden Rice.

Oh, wait. Maybe that’s not such a good idea…

How about donate $100 to your favorite mainstream media outlet, since they are having so much trouble convincing the public that Al Gore was right about Manbearpig after all?

Or donate the $100 to Al Gore directly, since he is allegedly being cheated out of millions of dollars of Big Oil money from his sale of Current TV to Al Jazeera. Poor guy. :-(

So, show everyone you care about global warming! Dump some ice water on your head!

(But don’t use any from the Arctic Ocean! There’s almost none left there anyway!)

Humanity is depending on you!

Wikipedia Page on Propaganda Techniques Uses 97% Meme

August 20th, 2014

If 99 billion mouths agree, shouldn't you?

If 99 billion mouths agree, shouldn’t you?

Oh, this is too rich.

I’ve blogged before on how global warming alarmists use all of the standard propaganda techniques to convince the not very super-sophisticated masses, and I listed Al Gore’s own statements as examples.

Well, it turns out the “97% of all scientists agree on global warming” meme is being used as an example on the Wikipedia Propaganda Techniques page:


Bandwagon and “inevitable-victory” appeals attempt to persuade the target audience to join in and take the course of action that “everyone else is taking.”

Inevitable victory: invites those not already on the bandwagon to join those already on the road to certain victory. Those already or at least partially on the bandwagon are reassured that staying aboard is their best course of action. (e.g., “The debate is over. 97% of scientist agree”)

I wonder how long the example will stay there, without William Connolly to play gatekeeper. I also see “Hope and Change” is given as an example. Hmmm…sounds vaguely familiar.

Of course, Tom Steyer’s recent claim that 99.5% of the country is not “super sophisticated” when it comes to global warming beliefs is belied by the fact that research shows the more educated you are in math and science, the more likely you are to be a skeptic.

Being super sophisticated doesn’t mean being smart.

New Orleans Hurricane Exactly 9 Years After Katrina?

August 19th, 2014

It’s still over a week away, but a tropical disturbance east of the Lesser Antilles is being forecast by the GFS model to grow into a hurricane, making landfall near New Orleans just 1 day before the 9th anniversary of Katrina’s landfall:

Nine day forecast of 850 mb circulation and temperature from the 12Z GFS model run on 19 August, 2014.

Nine day forecast of 850 mb circulation and temperature from the 12Z GFS model run on 19 August, 2014.

Needless to say, it IS hurricane season, so a Gulf of Mexico hurricane in late August (near the peak in the season) is not that unusual.

But note the 2014 season is supposed to be relatively inactive:

Of course, this far in advance, the hurricane (even if it forms) could make landfall anywhere along the Gulf coast. I just thought the timing and location, exactly 9 years after Katrina, was interesting.

Thermal Imaging with your iPhone

August 19th, 2014

This is SO cool.

FLIR Systems now has an iPhone add-on that turns your iPhone 5 or 5s into a thermal imager, for $349. (In contrast, my FLIR i7 imager was, as I recall, $2,000.)

FLIR One thermal imager back for the iPhone 5 or 5s.

FLIR One thermal imager back for the iPhone 5 or 5s.

Called the “FLIR One“, I think these are going to be pretty popular, and I’m sure the price will come down over time.

There are many uses (besides the gee whiz factor). You can see in the dark with it, see small animals in the woods, identify subtle temperature changes associated with water leaks, overloaded electrical wires, find insulation voids in your walls, air leaks around windows and doors, tell when your girlfriend or wife is really mad at you, and open up a whole new world of cat photography on Facebook.

Who knows? Maybe we will even have reports from all over the world documenting the existence of the atmospheric greenhouse effect.

Contrary to the TV series 24, though, you can’t see through solid surfaces like walls and roofs with it. You can’t even see through glass windows, which are also opaque in the infrared. But anything that subtly changes the temperature of the surface of a wall, like the presence of pipes or studs, can usually be seen.

I suspect that law enforcement and the bad guys will both be using it to gain an advantage. I won’t go into the ways in which that might happen.

The specifications for the FLIR One show pretty high sensitivity (0.18 deg. F), but a fairly restricted range of temperatures it will sense (32 to 212 deg. F). On the plus side, it also has a visible light camera and offers a visible/IR blending option for photos. It comes with its own battery, which is kept separate from the iPhone battery system.

Just to be clear…this is not an “App”…it can’t be done with just software. It has a microbolometer sensor array in it which receives infrared energy through a IR lens and measures the resulting tiny changes in temperature at each element in the array, then converts those changes to a pretty accurate estimate of temperature.

Since I recently switched from iPhone to Samsung, I’ll have to stick to my FLIR i7 imager for now. Oh well.

Climate Polling Results Lead to Weird Press Coverage

August 13th, 2014

A recent polling of Americans on their attitudes about how much scientists know (or claim to know) about global warming, as well as what should be done about it, has led to very different treatments in the press, specifically in the Pittsburgh Post-Gazette, which commissioned the poll.

The PG’s editorial take on the poll is that it shows that most Americans aren’t really that committed to the issue one way or the other. It suggests that the new poll questions were phrased in an unbiased manner (not assuming, for example, that global warming was a problem that needed to be dealt with), unlike previous polls claiming wide support for government action to reduce carbon dioxide emissions.

But the Post-Gazette also ran an op-ed by the pollster himself, who made it clear that Republicans are blind to established “facts” and only resist action on climate change because conservatives don’t like big government. The title of that op-ed made his views pretty clear: “Not a mystery why Republicans are blind (to) facts on climate change“.

The poll report itself is much less partisan in its comments — despite being authored by the same pollster!

The bipolar treatment by the newspaper makes the whole issue even more confusing for the reader.

But it is an interesting observation (which is widely recognized) that conservatives tend to disbelieve the supposed “scientific consensus” on global warming, and liberals tend to embrace it. The claims of ideological bias on the part of conservatives can cut both ways, of course. I can claim that liberals only believe the science because they are in favor of big government. So there.

The point I keep trying to emphasize is that not all science is created equal. Putting a man on the moon was immensely easier than understanding what factors cause the climate system to change, and especially by how much. We know the average energy flows reasonably well; but climate change involves less than 1% changes in energy flows, and we don’t understand the system that well.

When climate models can’t even hindcast global temperature changes in the last 30-40 years — where the answer is already known — how can we rely on them for forecasts?

It isn’t rocket science…it’s actually much more difficult than that.