Author Archives: Ugo Bardi

Ugo Bardi teaches physical chemistry at the University of Florence, Italy. He writes on sustainability, peak oil, climate change, resource depletion and other subjects related to sustainability on his blog "www.cassandralegacy.blogspot.com"

Stopping climate change is not just a good idea, it should be the law!

The Gummi Bears riding their “quick car” in the tunnels of the Gummi Glen. In this animated TV series of the 1980s, the characters were always shown buckling up before riding their quick car. At that time, seat belts laws were not yet commonplace and w…

The Song of the Gallic Rooster

Post by from “The Oil Crash” – Translation from Spanish by Max Iacono

As another example of the complex relation of mineral depletion, the economy, and the tendency of grabbing what is left, one way or another, this article by Antonio Turiel sheds plenty of light on the difficulties that the nuclear industry has in obtaining a steady supply of uranium

by Antonio Turiel

“All told,” I say, “I would say that if France has invaded Mali,  it’s for the uranium.  You know that don’t you?”  

“Of course I do!  Everyone knows it.”

Night was falling,  cold,  rainy and dark,  over Bordeaux.  I found myself looking at my friend, once my boss.  He was looking at the ground and then continued in a calm voice:

“France has 89 nuclear power stations, 59 of which are commercial.  83% of the electricity produced comes from nuclear sourcing.  We can’t do without uranium.”

I didn’t say anything and we continued walking.  I had lived for several years in France and at the time I didn’t quite understand how to interpret the curious display of cynicism and pragmatism with which the French public accepted certain kinds of barbaric actions  which their government committed in the name of “La France”.

*******

For a few weeks, France has been at war.  Several thousand soldiers and dozens of armored vehicles have been deployed to the battlefront in Mali.  The objective:  to prevent the advance of the Islamic front which has rebelled in the north of the country after the fall of Gheddafi in Lybia, and also due to the fear that the country could transform itself into one of the various nests of Jihad which is threatening the western world.  Or at least this is, broadly speaking, the official explanation.

Gheddafi had kept himself in power thanks to mercenary units formed starting with various Tuareg desert tribes,  and these mercenaries,  -upon the fall of the Lybian dictator, -and together with the training and military equipment they had received,- took refuge with their cousins in Mali.  In Mali and in Niger, for several years and periodically from time to time,  various armed groups rebelled calling for and seeking better living conditions for the Tuareg.  However this time their military capacities were considerably more significant.  In just over a year the Tuareg took control of two thirds of the country and without Mali’s weak and corrupt army being able to do much to stop them:  That the problem has the character of a civil war is evidenced also by the fact that not just a few of the various army units switched sides, something also indicating that Mali’s government does not have the unconditional support of its population.

In fact before France began its bombings on the 11th of January, both factions had agreed to a cease fire and were negotiating a peace accord.  Nonetheless, France pretended to present the internal conflict as a battle for democracy and against Islamic fundamentalism and organized a coalition of African countries as a defense force.   And this, so as not to appear like the old colonialist power which interferes in the affairs of its ex colony.  And it even managed to secure a UN resolution to justify the intervention.  But the support of its allies was nonetheless lukewarm.  Other than some words of support from the United States and some cargo airplanes from its European allies, France found itself alone in its fighting in Mali, while the African coalition force is yet to arrive. The fact is that France started to deploy its troops without waiting for anyone else as soon it found itself facing the real possibility that the government of Mali could fall,  and that the Tuareg could come to power.

What is driving France in this manner in Mali?  It is neither petroleum nor gas, primary resources whose potentially exploitable quantities in the country are not significant,  and which also easily could be obtained elsewhere.  Nor is it the precious metals that the country is rich in.  Rather, what is driving France to act at this time is uranium and, moreover, from a double perspective, that is, both short-term and long- term.

In the long term exploiting the uranium mines in Mali will be fundamental to satisfying the Gallic hunger for uranium on which depends its entire industrial model – one of which they are also often proud,  given that they consider the nuclear energy which is produced as indigenous (notwithstanding the fact that the base fuel, uranium, is obtained outside the country)

The quantities of uranium in Mali are significant but not spectacular, -(if one considers that at Falea there are roughtly 5,000 tons of natural uranium which is equivalent to recharging ten times – once every 18 months-  a nuclear power plant of one Gigawatt capacity,   and that the exploration phase for additional uranium is not even yet complete)  But in any case, these mines will be indispensable in the future.  And in the short term, the aspect for which Mali is crucial for France is for the transportation of uranium from Niger – not to be confused with Nigeria.  This is indeed truly fundamental for French industry:  One third of the uranium which is consumed in the old metropolitan country comes from the territory of Niger.  And the uranium resources of Niger are truly important and significant and  are among the largest in the world….

France has suffered many setbacks in Niger, which just like Mali , is one of its old colonies.  Throughout the years the governments of Niger have been rather docile and have allowed the extraction of their uranium at low cost and without having to include or internalize the costs of the environmental damage that extraction generated.  The majority of the mines are open-pit surface mines which degrade the living conditions of the peoples of Niger nearby, who often have been placed under military influence or control whenever that became necessary.  This has generated frequent revolts, strikes and increasing difficulties for the exploitation of such mines,  also due to the armed persecution on the part of separatist groups near the border with Mali.   In fact certain experts are of the opinion that behind the precipitous French action there was also the need to reinforce the security of the mines, and the observable  facts tend to confirm this directly.

To the difficulties of exploiting Niger’s uranium which already existed for some years,  now also can be added the more recent competition in the field with China, which has obtained various mining concessions in Niger and is expanding rapidly its own operations in that country.  Incapable of competing with such a powerful country,  the French company Areva opted for seeking collaboration and partnership in some mining projects, also in an attempt to lower its costs.  And this is fundamentally because the resource which it desperately needs is becoming ever more scarce, expensive and dangerous to extract in addition to now also having to be shared.

All of this scarcity on the part of our cousins on the other side of the Alps (the original article was in Spanish) takes place in a general global context  which is not at all flattering or encouraging:  Uranium is becoming more rare and scarce.  At the moment a relative stagnation is occurring in its extraction. :  According to data from the World Nuclear Association,  2012 is the the second year in a row during which global extraction has decreased.  (54,660 tons in 2010, 54,610 in 2011 and 54,221 in 2012)  Even if such oscillations of production which are observable in the historical data -coupled also with the Fukushima disaster- have decreased slightly uranium demand, there continues to be a considerable difference between the uranium which is extracted and that which is consumed;  the latter having been up to now covered by the re-cycling of uranium from Russian nuclear warheads that were being dismantled in keeping with the Megatons to Megawatts program.  Unfortunately that program will run out precisely this year, in 2013, and will not be renewed or continued, and therefore we also can expect a deficit of uranium whereby one easily can foresee a fairly serious scenario of fresh problems in its supply;  and perhaps even the precipitous arrival of the feared “peak uranium”.  And it is within this ever more tense and tight market for uranium that France is now playing out its own “raison d’etre”.

This war by France is yet another of the various wars for resources, similar to other preceding ones, and to others which will follow it.  The only thing which differentiates it from those which surely will follow it, is the extent of desperation by the aggressor.   The Industrial France which arose again with force in the twentieth century,  is now agonizing.  Its financial condition is not nearly as good or as healthy as is thought,  and probably will become prey to the same vultures which have not stopped observing and watching Spain, even if at the moment the opposite is being pretended.

France is playing with an important part of the survival of its industrial model in trying to assure its supply of uranium from Niger and Mali.  If it were now to fail, the vacillating economic and industrial fabric of France would not be able to allow itself another war.   This war is the Song of the Proud Gallic Rooster.  Perhaps its last.

Cheers, AMT

The important thing is to do something

A post by Max Iacono, inspired by the post by Ugo Bardi on the meeting on climate change held in the town of Fiesole


by Max Iacono

A meeting such as the one whichtook place in Fiesole easily could be viewed as the first in a longer series of stakeholder meetings convened as part of a participatory local economic and social development program lasting several years.   Two “development” paradigms or models come to mind here.  One is “community development” and the other is “local economic development” or more generally “local development”.  “Local development” is a more encompassing term which can include local economic, social, political/ governance, cultural and environmental kinds of development; and an adequate local response to climate change can be viewed as engaging in a particular type of “local environmental development” program; in reality the various “dimensional” types of local development mentioned above all are inter-related and mutually supportive or constraining.

Without going further into the distinctions between community development and local economic or other kinds of local development each pursued in different ways  -since the international experience is wide and diverse- it is useful to note that often participatory local development initiatives begin with an assessment of the current situation in which the locality finds itself;  the local stakeholders look at both problems and opportunities which the community faces and then try to identify strategies and programs to self-develop the locality or community to which they belong.  If the meeting in Fiesole -or in the countless other localities throughout the world where it might have taken place- is viewed in this way, then the meeting might be seen as only the first in a series of many geared to assessing local problems and needs, developing strategies and then implementing an appropriate set of practical measures and actions. 

It is of course very difficult -in fact impossible- to know in advance what practical measures eventually should or could be implemented by local stakeholders at the community or local levels in the millions of communities and localities existing throughout the world  to mitigate against climate change and its many diverse effects in each particular place.   These measures by necessity will vary enormously from place to place and context to context.
One fairly obvious general effect of climate change however is that the weather is getting “wilder” in various ways.  So there are  -and there will continue to be- more droughts, more fires, more very heavy rainfall or snowfall, more floods, more hurricanes,  more tornados, and seasons that are ever more out of kilter -e.g. longer or shorter and more intense summers or winters- thereby also affecting agriculture in various and differing ways,  as well as plants, trees, animals, insects, pollinators, vector-borne diseases and etc.
It would seem that the first thing any community or locality would need or wish to do is to understand:  i) how exactly it is being affected already in some of the ways above or in other ways over any single calendar year period;  and ii) how  is it most likely going to be affected in let’s say another five years based on current trends in the worsening of climate change.  Since this is the most probable scenario because parts per million of CO2 continue to increase by about 3 ppm per year and increasing quantities of methane also are being released and more ice melt also is occurring.   But it also can be useful to look at the history of severe weather events in the locality and around its general area over the past 50 to 100 years, if it is available.   This is because a flood that before might have occurred only once in every 100 years now might occur on average once per decade.  

Once this first general assessment is done it will be easier for local stakeholders to discuss sensibly what might be done and what could be planned and done by the local community,  or by the province or the region or the country within which it is set. 

The other aspect which I think any local stakeholders probably need to understand is the difference between various kinds of actions and measures which are possible and namely those which belong in four categories:  i) prevention ii) mitigation iii) adaptation and iv) reversal.  Measures implemented in one category may have effects in some of the other categories too but generally speaking there are different measures for different objectives.
 
For instance although Fiesole may wish to focus on preparing better for any fires which may occur, nothing prevents its residents from also being aware of what is involved in the Keystone pipeline decision in the United States which will affect prevention probably more than any other single development at this time. And although I wouldn’t necessarily advocate it because I think it would be mostly ineffective, they also could write a letter about it to president Obama so that he at least might know that people all over the world are watching what he does or fails to do.  Doing something about preparing for fires  (mitigation locally) while writing such a letter (prevention internationally) would help to synergize and further activate the concern and action for climate change by those involved.  The important thing is to actually do something and to remember that it is mostly by doing –and often by trial and error- that we learn ever more about what to do and how to do it and develop further both our capacities and our confidence and motivation for taking further action.

Ian Dunlop: an emergency war footing action against climate change


Ian Dunlop, is an energy expert, director of “Australia 21,” member of the Club of Rome, and more. On climate change, he is an extremely effective speaker who doesn’t do any pill sugaring; as you can see in the video above. The slides he presents are also avaliable on-line. From this set of slides, here is the conclusion:

The climate & energy challenge is far greater & more urgent than is acknowledged officially

“Official” solutions, and current processes, are not working and will not deliver the required transformation either to the extent, or in the time, required.

Market forces will not deliver without fundamental regulatory change.

If we are serious about avoiding catastrophic outcomes, emergency “war-footing” action is essential

“It is no use saying ‘we are doing our best’, we have to do what is required.” 

Winston Churchill

The Arctic is the real canary in the coal mine!

While the „denialosphere” is desperately trying to develop just-another-misunderstanding of climate science (search for “global warming stopped” meme), there is another *real* issue. Specifically, the last time planet Earth enjoyed carbon concentration at around 400 ppm for a longer time period, average summer temperatures in the Arctic region were significantly higher.

According to the latest and most comprehensive paleoclimatic analysis, which brought us high resolution temporal data back to the Pliocene (Brigham-Grette et al., 2013, Science), summer temperatures in NE Arctic region were ~8 °C higher compared with present-day climatology.

There are tree recent paleoclimatic temperature reconstructions from the Arctic region. Two of them are presented in the following graph:


The graph shows temperature anomalies (relative to 1960-1990 climatology) during the summer in the Arctic region with a 10-year resolution in the last 2000 years (Kaufmann et al., 2009) (txt tfile). The second reconstruction shows a newer analysis (Shi et al., 2012) (txt file), based on more proxy data and with yearly time resolution. The shortest curve represents the instrumental temperature records according to NOAA (1880-2010) for the summer temperatures in the Arctic.

The fit of the two paleo-reconstructions is not perfect, but the trends are similar and warmer, as well cooler periods in the past can be observed – the well known “Little Ice Age” and “Medieval Warm Period”. The recent “hockey stick” is also familiar to most people engaged in climate change discussion, since a similar trend is valid for the whole Nothern hemisphere and the planet.

But there is more. What we already knew is that as CO2 concentration continue to rise, global temperatures will do the same. The arctic region will warm even faster. Maybe some positive feedback loop will kick in. Maybe even more than one. But now things look even more complicated, since the recent work of Brigham-Grette et al. (2013) has shown us, what the area around the lake El’gygytgyn in the NE Arctic Russia (and by proxy also most of he Arctic) looked like last time, when CO2 concentration was approximately at the present level. Watch out:

Still concerned only about polar bears?This article was originally published at Neven’s Arctic Sea Ice Blog. There is also another excellent representation of human extremely complex influence on planet Earth, which many call “The Anthropocene”, not without a reason!

A comment by Ugo Bardi: The decline of Arctic ice is probably the most visually evident consequence of global warming. It is clear, obvious, impressive: no one can miss it. And with the troubles of the polar bears, you would think that no one could remain indifferent. You would think that a well argued and well researched article such as this one by Alexander Ac would have some effect.

Yet, the accumulating evidence fails to make a dent in the general indifference. News about the polar melting appear in the media, but they fail to generate a reaction: most people seem to be immune to memetic infection from Arctic news. In large part, this lack of reaction is due to the “Star Wars Force Push” effect. As Peter Sandman states, people react to emergencies in way that are far from being rational: “When somebody says something that people don’t want to hear – and certainly don’t want to have to think about or acknowledge – they sometimes self-mockingly stick their fingers in their ears and sing, “La-la-la-la-la.” This is a very literal representation of the essence of denial.

So, it is not enough to place the evidence in front of people: most of the times, they will just ignore it. Even if the canary dies, they’ll keep mining.

Truth is flooding out?


I don’t know what’s your impression; maybe I am biased, but I have this feeling of an acceleration, of something that’s boiling up in people’s minds. More and more people are entering the fray; and they are doing it forcefully and with strong arguments. And not just scientists: people with different backgrounds and abilities are coming forward. The latest one I stumbled upon is Gaius Publius; again not a climate scientist. It is very well written and an example of how to communicate the danger of climate change. Is truth finally flooding out?

The climate crisis in three easy charts

5/1/2013 9:00am by  

I’m preparing to pivot back to climate crisis, starting with some reformatting of the earlier Climate Series posts — the transition to WordPress wasn’t kind to them — and the organization of this material into book form. (There’s also a climate-themed novel in the works; thriller fans, stay tuned.)
As a result, I’m doing serious study to refine both the concepts (or rather, the explanation of them) and the dating of coming events (the crisis in its various stages).

The first part of that pivot includes two media appearances this week. I’ll be on Virtually Speaking With Jay Ackroyd this Thursday (May 2) at 9 pm ET to discuss climate crisis for a full hour, followed by a Sunday appearance with Avedon Carol as part of the Virtually Speaking Sundays weekly media panel.
It’s the climate discussion I want to focus on here, and I’d like to do it by focusing on three diagrams and a few references back to my earlier climate pieces.

Climate catastrophe will usher in a new geologic era

Long-scale earth history is divided into Eons, then Eras, then Periods. But in fact, prior to the Cambrian Period, when life on earth exploded in number and variety, earth history is the story of non-life or small single- or multi-celled life. And starting with the Cambrian period, there’s just one “eon” anyway. It’s eras and periods we care about.

So let’s start there, with the Cambrian Period and the flourishing of life on earth. Consider the chart below:

Mass_Extinction_500px-Extinction_intensity.svg_2
The divisions across the top are geologic periods, starting with the Cambrian (“Cm”), the period of “visible life”‘ — meaning a proliferation of hardshelled species. It’s the big explosion of life on earth. The numbers across the bottom are millions of years ago. The spikes show extinction events, with the percentage of marine species going extinct expressed on the vertical or Y axis.
The chart doesn’t call them out, but starting with the Cambrian period, we’ve had three geologic eras (the larger divisions):

Paleozoic Era — “old life”
Mesozoic Era — “middle life” or the Age of Reptiles (dino days)
Cenozoic Era — “new life” or the Age of Mammals (including us)

The Paleozoic Era runs from the start of the graph to the big spike at 250 million years ago on the X axis. It encompasses six geologic periods and ended in the greatest mass extinction event on the planet — geologists call it the “Great Dying”.

The Mesozoic Era runs from the Great Dying at 250 million years ago to the big spike at 65 million years ago, the event that wiped out the dinosaurs — and every other large species. That cleared the way for mammals to grow big and thrive.

We’re now in the Cenozoic Era. Keep those transitions in mind — when mass extinctions change which groups of species can evolve and rule, it’s the end of an era and the start of another. Now look at the chart again. The whole chart shows 540 million years, and just three geologic eras. The next extinction event on the scale of the one at 250 million years ago, or the one at 65 million years ago, will change the shape of life on earth and usher in a new era. Ready for that?

[Update: For a chart that shows geologic eras, periods and their subdivisions in one place, click here. Opens in a new tab.]

Where does man fit in?

Great question — where does man fit in? Answer: We come in very late.
First, notice the last three geologic “periods” at the top-right in the chart above. The period marked “K” is the Cretaceous, the period at the end of the Mesozoic Era. The next period (“Pg”) is the Paleogene, the one that marks the start of the Cenozoic (new life) Era. The period after that (“N”) is the Neogene, which ended just 2 million years ago. The period after that, not shown, is the Quarternary Period, our current one.

The Neogene-Quarternary boundary is the start of the time of great glaciers, and the best way to show that is with the chart below, showing earth temperatures mapped across the geologic periods (at the left end) and geologic epochs (the rest of the chart).

Earth_tem_All_palaeotemps_700px

Click here to open the full version in another tab. It’s a big, interesting chart. (Source here.)

First, get oriented. On the Y axis is global temperature using change — in °C — from global temperature in the year 1800 as the norm or zero mark. (The global pre–Industrial Revolution temperature is generally the mark from which other global temperatures are measured, unless otherwise noted. To convert from °C to °F, just double the number; you’ll be pretty close.)
On the X axis, the first big division — from 542 million years ago to 65 million years ago — represents the first two geologic eras, the Paleozoic and Mesozoic (which unfortunately aren’t called out on this chart). “K” at the top and bottom is still the Cretaceous Period, and the end of the Cretaceous Period is also the end of the dinos and the end of the Mesozoic Era.

In this respect, both charts are the same. Man hasn’t showed up yet — our mammal ancestors were the equivalent of field mice in that world, small prey with soft shells and hiding skills.

But before we look at the rest of the X axis, notice that in the left-most part of the chart, the Y axis shows a huge change in global temperature relative to pre-Industrial norms. Looks like a monster spike, especially the first one, doesn’t it?


The Cambrian temperature spike is 6–8°C (about 11–14°F) higher than pre-Industrial levels. It’s also the temperature we’re headed for by 2100.

But let’s not get distracted. Let’s set some markers in this chart in the horizontal (time) dimension. The whole rest of the chart — the part after the period called “K” — shows the  Cenozoic Era (“new life” or Age of Mammals).

From here to the right, the chart’s subdivisions show Epochs, which are sub-parts of Periods.

[Update: For a chart that shows the relationship between eras, periods and epochs, click here. it will help you stay oriented.]

Jump through the next five divisions — the epochs marked “Pal” through “Pliocene”. That takes you through the Neogene Period (“N” in the first chart) and to the start of the modern Quarternary Period, the one we’re in, and the one we’re interested in.

The epoch of the Pleistocene, which starts the Quarternary Period (again, see the chart), is the great age of glaciers. Homo habilis evolves at this time, a little over 2 million years ago. Homo erectus evolves shortly afterward. Each starts in Africa — now you can probably guess why — and each leaves Africa and spreads across the globe. (Homo erectus, by the way, lasts a long time on this earth. Longer than us by a lot.)

Homo sapiens evolved much later, in the Pleistocene — the age of glaciers, remember — just 250 thousand years ago, almost died out in Africa, but rebuilt our numbers, then spread out of Africa like our cousins. Because that was the glacier age, we’re still hunter-gatherers like the the rest of our cousins. The big beasts of the earth are creatures like woolly mammoths and sabre-tooth tigers, and we’re all alive on a fairly frozen planet with glaciers coming and going.

At the end of the Pleistocene is another extinction event. At the same time that the last glaciers recede (see chart), the big mammoths and tigers (et al) die off. Simultaneous with a noticeable change in climate, what we call “human civilization” begins. You can see that above, around 12–10 thousand years ago [corrected] as the planetary temperature stabilizes. From then until almost now, planetary temperature is pretty stable. Notice it doesn’t take much of a wobble to mark the “Little Ice Age”.

Just two more points to make in this piece and I’m done.

First the bad news

Folks, that little climb in temperature you see near the right end of the graph above is just the beginning. Remember the Cambrian spike at the left end of the graph? Take another look and note the increase — about 7°C. Now here’s Figure 21 from the Copenhagen Diagnosis, a report prepared by … oh … every single one of the world’s top climate scientists for the benefit of our world’s “leaders,” who met in 2009 to discuss how to pass the climate buck one more time:

Copenhagen_Diagnosis_Fig_21_LARGE

What you see is temperatures from 500 AD to about 2000, with a number of prediction scenarios going forward. See the scenario called “A1FI”? It’s the one in red. That’s the one we’re on if we don’t stop spewing carbon. I call it the “do nothing” scenario — otherwise known as the “Keep David Koch Happy” scenario.
All you need to know? We’re on track for about +7°C — the peak temperature in the big Cambrian spike — by the year 2100.

Now the good news

Despite all this doom-and-gloom, it’s not over yet. Truly. By my calculation, we have a 5–10 year window to avoid the catastrophe. It won’t be easy — we’re past the point where any transition will be smooth — but we can make the transition and survive as a civilized species, humans in a recognizable world.
But two things are needed:

  1. This has to be our top priority, which means you and everyone you know has to be fully aware and in full battle gear. (For reference, it’s called “hugging the monster.”)
  2. It’s us vs. David Koch and all of his friends and enablers. Tackling any other enemy is tackling a dummy while the game is being played.

Educate your friends, and put a wrench into the Koch machine. How’s that not a plus?

If the Koch Bros keep getting rich, we move backward. If Barack “Hope & Change” Obama approves Keystone, we move backward. If the U.S. develops “domestic oil” resources, we move backward. For every new car (“carbon-delivery system”) sold, we move backward. People need to know this and think like this. We can stop the crisis, but only if we stop carbon. It’s that simple; and that stark.

But it’s also doable, and we’re the species that’s most equiped for “doable.” It’s what our big brains are for.

I’ll have more in the weeks and months ahead. I haven’t given up, not by a long shot. But you can’t pull out of a tail spin if you don’t admit you’re in one. Me, I think we can pull out.

[Updated for clarity and to correct two typographic errors, one in naming and one in the age of our species. We're 250 thousand years old, not 250 million. Also updated to add links to a chart showing all eras, periods and epochs in relationship to each other.]
GP

The climate tipping point

Via “Cassandra’s Legacy.” Also a perfect example of the phenomenon that I called the “Seneca Effect”h/t “The Cost of Energy”

The Seneca effect visually shown

Here is a perfect example of the phenomenon that I called the “Seneca Effect” and which is at the origin of many types of collapse.

It would be some consolation for the feebleness of our selves and our works if all things should perish as slowly as they come into being; but as it is, increases are of sluggish growth, but the way to ruin is rapid.“  Lucius Annaeus Seneca 4 AD – 65 AD

h/t Grinzo See also “The Frog that Jumped out

Michael Mann on the role of scientists in communicating the implications of climate change

 The book by climatologist Michael E. Mann is correctly subtitled “Dispatches from the front lines” because it tells the story of a true communication war. With his reconstruction of past climate termed the “hockey stick”, Mann had been singled ou…

400 ppm: time for a communication tipping point

Image from CelsiasThe round number of 400 ppm of CO2 concentration in the atmosphere has no special physical significance. The dreaded atmospheric “tipping point” that will lead us to climate catastrophe could have been passed already, or perhaps it co…