Hi Jeff,

It is expected that the CO2 mixing ratio in the atmosphere will keep on increasing. Not only that, it will probably increase its rate of increase as well. If we reduce CO2 emissions by 30 % over the next 10 years, population growth will anihilate the reduction of emissions, since these additional folks, will need food, water, power, transport etcetera as well as we do now. I say it again, as long as population growth is not under control, CO2 will keep increasing ever faster.

This will with quite some certainty lead to the inundation of many cities against the end of this century. How come? Take Miami in Forida. It is about 20 to 30 cm above sea level. It does not have any dikes, or any other infrastructure to defend itself against flooding by an increased sea level even when it is only a mere 20 tot 30 cm.

Problem for humanity is that the most fertile land and most of the human population is found within a distance of 300 km from any coastline. This means that a vast majority of the world population lives close to seas and oceans.

Look at Bangladesh, The Netherlands (which has land permanently below sea level (below low tide!), but the best engineers at the level of flooding defense infrastructure buidling. Bangladeshi, swamp each year in the Monsoon floods. India has even built a wall at the Indian Bangladeshi border, to keep the 150 million Bangladeshi out of India, when flooding occurs. Remember the big flood of New Orleans. During that flood, dikes were destroyed at 50spots, due to their deplorable state. Now billions are invested to try to stop the sea from visiting New Orleans once more devastating it as it did during the first big flood. The dutch learned their lesson in 1958 with a big flood with 2000 people drowned. From then on they started the building of a defense line at the great rivers delta (Schelde, Maas, Rhine) and they closed off the Southsea (Zuiderzee) from the North Sea with a huge dam.The techniques they have developed since then are an example for many countries and their coastal cities which will get into peril pretty soon as well.

The Third world war wil be a battle against the surging seas. It has been estimated that 90 % of all land ice is located on Antarctica. Much of the rest is found on Greenland. Assuming that all this would melt and dissappear in the oceans, sea level would rise with an impressive 70 meters. That would mean the en dof London, Paris, almost the complete Netherlands with 16 million people, and lots and lots more. Civilians would start moving around to higher ground, but 40 % of all arable land would dissappear under sea.

Is this science fiction? Am I hallcinating? I will not be alive when this happens, and not even my children. But the children of my children might belong to the first Belgian migrators to higher ground, or sea dwellers, living on floating cities, like the Dutch are planning right now. Quite some Dutch folks actually live on boats as we speak.

But how about food? Go to war for arable land and sweet water reservoirs on higher ground? Does not look good does it.

I hope that New Orleans, was just a meteorological mishap, but many believe that it might be the beginning of more. Honkong, Shangai, Beijing, Macao, Singapore, Bangkok, Bangladesh, the Ganges valley, the Brahmaputra valley, the Pearl River, Jakarta, the Schelde - Maas - Rhine delta, the MIssissipi delta, Buenos Aires, Rio de Janeiro, Washington, New-York, The San Francisco Bay area, Seattle, Rotterdam, Amsterdam, Den Haag, Hamburg, Bremen, Antwerp, Kopenhagen, ... Keep watching folks, which one will be next?

Cheers,

Frank

Good question. It seems to me that atmospheric CO2 concentration will not flats off as soon as we would like to. So, maybe, prevention fits better.

Hi Jeff,

It is expected that the CO2 mixing ratio in the atmosphere will keep on increasing. Not only that, it will probably increase its rate of increase as well. If we reduce CO2 emissions by 30 % over the next 10 years, population growth will anihilate the reduction of emissions, since these additional folks, will need food, water, power, transport etcetera as well as we do now. I say it again, as long as population growth is not under control, CO2 will keep increasing ever faster.

This will with quite some certainty lead to the inundation of many cities against the end of this century. How come? Take Miami in Forida. It is about 20 to 30 cm above sea level. It does not have any dikes, or any other infrastructure to defend itself against flooding by an increased sea level even when it is only a mere 20 tot 30 cm.

Problem for humanity is that the most fertile land and most of the human population is found within a distance of 300 km from any coastline. This means that a vast majority of the world population lives close to seas and oceans.

Look at Bangladesh, The Netherlands (which has land permanently below sea level (below low tide!), but the best engineers at the level of flooding defense infrastructure buidling. Bangladeshi, swamp each year in the Monsoon floods. India has even built a wall at the Indian Bangladeshi border, to keep the 150 million Bangladeshi out of India, when flooding occurs. Remember the big flood of New Orleans. During that flood, dikes were destroyed at 50spots, due to their deplorable state. Now billions are invested to try to stop the sea from visiting New Orleans once more devastating it as it did during the first big flood. The dutch learned their lesson in 1958 with a big flood with 2000 people drowned. From then on they started the building of a defense line at the great rivers delta (Schelde, Maas, Rhine) and they closed off the Southsea (Zuiderzee) from the North Sea with a huge dam.The techniques they have developed since then are an example for many countries and their coastal cities which will get into peril pretty soon as well.

The Third world war wil be a battle against the surging seas. It has been estimated that 90 % of all land ice is located on Antarctica. Much of the rest is found on Greenland. Assuming that all this would melt and dissappear in the oceans, sea level would rise with an impressive 70 meters. That would mean the en dof London, Paris, almost the complete Netherlands with 16 million people, and lots and lots more. Civilians would start moving around to higher ground, but 40 % of all arable land would dissappear under sea.

Is this science fiction? Am I hallcinating? I will not be alive when this happens, and not even my children. But the children of my children might belong to the first Belgian migrators to higher ground, or sea dwellers, living on floating cities, like the Dutch are planning right now. Quite some Dutch folks actually live on boats as we speak.

But how about food? Go to war for arable land and sweet water reservoirs on higher ground? Does not look good does it.

I hope that New Orleans, was just a meteorological mishap, but many believe that it might be the beginning of more. Honkong, Shangai, Beijing, Macao, Singapore, Bangkok, Bangladesh, the Ganges valley, the Brahmaputra valley, the Pearl River, Jakarta, the Schelde - Maas - Rhine delta, the MIssissipi delta, Buenos Aires, Rio de Janeiro, Washington, New-York, The San Francisco Bay area, Seattle, Rotterdam, Amsterdam, Den Haag, Hamburg, Bremen, Antwerp, Kopenhagen, ... Keep watching folks, which one will be next?

Cheers,

Frank

I understand a tipping point to indicate an irreversible and substantial change in regional to global climate that will have adverse effects on society. I think this is a serious issue and a great question, and I think the honest answer is that we do not know.

We may already be past that point, or it may still be decades in the future. What we can say for sure is that the probability of passing a critical point in this way increases with each added ppm of greenhouse gases. So much depends on climate sensitivity both over the short and long terms. The greatest probability is that we will see an increase in temperature around 2-4 degrees for doubling CO2 emissions and I believe that this outcome is what we need to address.

Politicians in the USA, however, prefer listen to those who think sensitivity lies at the low end of the range. I consider this an egregious error. Because of this I believe that we will not find a global political/economic solution for some time to come (especially with growing unease and geopolitical tension). We may see progress by the middle of the Century when we see regional tipping points collapsing around us and can then measure the full financial and human consequences of procrastination.

Given this (dire) prediction, I think we need to pay even greater attention to coping, adapting and mitigation where possible. The challenge so well illustrated by Frank is that this burden falls unreasonably on the developing world that lacks the resources to achieve progress. This is an equal global challenge as that of limiting the emission of GHG. One thought to Frank... I understand that sea level will rise, and that this will have an impact on many communities in the lifetime of our students, but the kind of totally catastrophic rise you envision- while a well played theme in geological history- is at least centuries if not millennia away. Belgium and the Netherlands have the resources and technology and adaptive capabilities to manage a climate transition for a long time to come and are good examples of how nations learned to cope, adapt and mitigate the impact of a relative rise in sea level with all the floods and storm surges that come with that. In my opinion Bangladesh has also made great strides forward is disaster preparedness and recovery (compare with Burma) but they need your help and expertise (and a great deal of our money) if their (existing) coastal communities are to survive the end of this century. So... cope/adapt/mitigate.

This is triage. Deal with the immediate problem and then go deal with the source.

http://www.amazon.com/Global-Climate-Change-Turning-Knowledge/dp/0321634128#

Hi!

The IPCC WGII report on impacts and adaptation released last monday concludes that both mitigation and adaptation are important. Adaptation should be mainstreamed for two main reasons: 1) the lack of satisfactory mitigation efforts and 2) the fact that even if mitigation policy were successful severe impacts will occur in the following century (what it is known as the inertia of the climate system).

Regarding the 400ppm, here you are a link to a policy brief that researchers from BC3 prepared a few months ago, I think you may find it interesting:

http://www.bc3research.org/index.php?option=com_pbriefings&task=showdetails&idpbriefings=27&Itemid=292&lang=en_EN

Cheers.

Elisa

Hi David and Elisa,

Yes indeed, we will first have to cope with impacts, and subsequently or preferably concomitantly deal with the source of CO2 emissions.

I agree about the 70 meter sea level rise. It is a quite hypothetical example, which is based on the assumption that if all land ice (Antarctica and Greenland) would melt, the sea level would rise about 70 meters. That's about the maximal sea level rise which can be expected so to say. But we do have to take account of a sea level rise of about 1 to 2 meters against the end of this century. As I stated, since many cities and highly fertile arable land are located in a zone from below sea level (The Netherlands, Belgium) to 2 meters a.s.l. (many other coastal area's on the globe), our hydraulics engineers better start thinking when to kick-off with the second Delta and Sigma plans for the Netherlands and Belgium respectively and other plans for other countries which will have to cope with the same problem. WHEN to (not how to, the know how is there!) protect coastal cities and arable land.

This means that the new techniques which have been developed will have to be applied for dike building (these techniques exist as we speak) which allows to heighten dikes when needed, e.g. when the sea level reaches a point where statistically speaking the combination of a storm tide (wind driven) and a spring tide (extreme high tide with sun and Moon exerting maximum gravity) will cause flooding in estuaries in Europe and elsewhere.

For Antwerp at this moment the risk for this type of flooding, as we speak, is once each 30 years. But that number declines bit by bit, each year. So what is statistically acceptable and what is not? A question for our politicians? For our engineers? Or for the citizens living in cities under threat of flooding?

When we think about the tipping point, I guess that this type of questions and problem area's are typically related to the tipping point problem. What (expressed in a number of years) do we consider as an acceptable risk on flooding and what not? This is a pretty enigmatic question?

Moreover depending on the policy adopted by however sits on the flooding defence budgets, for some of them 30 years is acceptable and for others it is not. For sure, the citizens of Antwerp, Rotterdam or Den Haag will find this not acceptable. But who will pay for the billions (trillions?) of euro's / dollars needed for the large investments going along with buidling the flooding defence infrastructure?

So even coping with sea level rise will be a tough job, with sooner or later a heavy impact on national and global economies. The building of the pyramids is nothing compared to what I think lies before us with respect to builing defence lines against sea level rise.

I really hope I am too pessimistic.

Cheers,

Frank

Dear Frank,

I am afraid society is not very much concerned about climate change unless affected by, for example, an extreme event like flooding. Flooding is going to be a huge challenge for the Basque Country as well and you are right, there are many infrastructural adaptation measures that are going to be extremely expensive. Cost-benefit analyses could help the decision-making process (what, when is to be made). We tend to focus on infrastructural/engineering solutions but I would like to stress that there are many other adaptation options that could be considered, such as, ecosystem-based adaptation (wetland restoration, for example), early warning systems, insurances, behavioural changes.

In any case, I do agree with you that it is time for decisions and adaptation plans (particularly at the local and regional levels) are going to be key instruments to lessen the impacts of climate change. At the same time, let's hope that the world agrees on a mitigation agenda.

Have a nice Friday.

Elisa

I agree. This all makes so much financial and strategic sense. The solution seems so rational and obvious. Invest now to save for the future. But then I look at the two countries that need to engage most-the USA and China, and wonder if global priorities are likely to take precedence over regional and national priorities.

I think we will see progress in both countries, perhaps even more in China because they have further to travel to get to where they need to be, but I listen here each day to the news and hear views that represent (at the very least) a large minority in the USA and I do see the level of concern needed to drive the political solutions we need.

The USA (full disclosure, I am Irish) has leadership at local and regional level where decision making and policy is driven by factional ideology and theology not fact-based research, and where there is a deliberate and coordinated and very successful climate countermovement that is disseminating doubt and uncertainty where it does not exist. Under these circumstances I see no prospect of progress at international level. In the long-term the human cost will eventually drive change. What a price that is to pay for hubris.

Hi David,

Do you mean to say that the New Orleans flooding didn't really trigger US public opinion with a wake up call? What I do remember form the New Orleans ordeal is that locally (Louisiana and New Orleans) and federally, the US government) made a mess of the decision making processes needed to soften the pain of being for the local population after the catastrophy in New Orleans.

I have seen a very critical flooding situation in Holland about 5 or 6 years ago. Heavy rains caused the Rhine to rise to less than a few cm from the top of its dikes. Since, the risk for flooding was imminent, the Dutch government with the help of Rijkswaterstaat (Ministry of water defence and public infrastructure), evacuated close to 300.000 people from a danger zone in two days. They also took care that the army and police force protected the left alone houses, shops etcetera, against luting an burglary. Anybody caught in the danger zone, went straight to prison. It did not come to a flood, but it had been very critical. Not one house had suffered from theft or whatever. Folks found their houses as they had left them. When I compare that with New Orleans at the time, my eyes were rolling around from unbelief.

Cheers,

Frank

If I may comment on the earlier discussion about rising sea levels and coastal flooding, the average sea-level rise in the time frame 1870 to 2010 has been about 2mm/year. Over the last 20 years it has been about 3 mm/year. However, if you look at the data, the rate during the 20-year period from 1930 to 1950 was also 3mm/year, while the period 1910 to 1930 saw almost no increase. This indicates to me that rate of sea-level rise is a stochastically varying quantity with a mean value of approximately 2mm/year. The assumption that the rate of increase will continue to rise is a hypothesis which is not justified by the historical data.

On this basis, sea levels will be 20 cm higher in a hundred years time, not 2 metres higher. As for the Antarctic melting, may I point out that the current extent of Antarctic ice is the greatest since measurements began in 1979.

Well Roger,

Then you throw overboard the local conditions in a lot of estuaries over the Globe. The last 50 years the high tides in the Schelde river estuary increased with more than a meter. And low tide my dear colleague did not change at all! Strange no? Nevertheless the tidal amplitude in the estuary of the Schelde river keeps increasing (linearly). It has even urged the city of Antwerp to built a defence dike along the river to keep the river out of the city with a NW storm and springtide. The probability of the occurence of these conditions which can lead to massive flooding, as I have explained in this thread increases each year.

Something tells me (what about logic?) that this is not stochastical behaviour at all. Even more, the Channel between the British Isles and mainland Europe acts like a funnel, leading to tidal amplitudes along the French Northern coastline of close to 10 meters. There is nothing new about his phenomenon. In the US there is even an estuary where the tidal amplitude goes up to 14 meters. That, by the way is the biggest tidal amplitude observed in the world. Impressive no? Again the US is the biggest.

I interpret these high amplitudes as amplifiers of the average Ocean tidal amplitude (Atlantic) which according to your opinion is stochastic in nature.

How do you explain then, that in French, Belgian, and Dutch estuaries, tidal amplitude increases linearly? Why do you think the Dutch and Belgians massively invested in sea defence with their Delta and Sigma plans? Maybe these countries are small, but there are potentially about 15 million Dutch and Belgians that can drown when we don't cope with the trends we keep observing.

I am listening to your suggestions Roger. Don't give me the example of New Orleans will you?

Cheers,

Frank

I'm not qualified to comment on European tidal conditions, so I won't attempt to. However, I will mention one fairly recent incident in the USA, the so-called Superstorm Sandy which flooded much of New York. The immediate response by much of the media and by the Mayor of Mew York was that this was an obvious result of climate change. Further examination then revealed that storm surges of this magnitude have historically occurred every 30 or 40 years or thereabouts. The difference this time was that the banks of the Hudson river had in recent years been encroached upon by various land reclamation projects, so that when the surge occurred the water was funneled into a much narrower channel than previously, with the result that water levels rose alarmingly. In this instance, at any rate, flooding was due to man-made development, and not a climatic change.

Roger,

The IPCC, and scientists working in extreme events, are VERY careful not to link one single event with climate change, and the recently released report follows the same line. So one thing is science-based evidence and another thing is politics, general opinion and media. What I mean is that Sandy might not have been related to climate change, but the evidence show that extrnes of this kind will most probably happen more often. So, what can we do? 1) mitigate and 2) adapt, which involves measures like avoiding building on flood-risk areas, dike construction, early warning systems, etc.

And for doing so is also very important what decision-makers, like NY's major think on the issue...

very hypothetical. simply we do not know the effects of threspassing such a level. actually, even emission increase, we are not experience increasing temperature trend (230 monthes without increase). So, a bug in our kownledge. Why we must introduce the missing heat in the ocean? This pretty looks like the 'etere' problem. I do not want to say it does not exist a climate problem, I want only to make a warning about concepts like 'tipping points' in absence of a clear knowledge

Hi Teodoro,

I think I just made clear that at the Western coasts of Europe a lot of tidal data (going sometimes back to more than ten decades) as well as hydraulic studies and modeling have been conducted.Sandbank shifts are followed with sonar remote sensing from hovercrafts. We know exactly what's happening man.

Within the next 3 years dikes will be removed from a big polder area (by the Dutch) in the Schelde river estuary, to create one of biggest floodplains in a European river estuary, thereby getting the increasing tidal pressure off on the Schelde river with its ever increasing high tides. Ain't that clear enough? We are talking about the future of millions of people in the European low countries my friend. We have already started the fight to keep our heads above the high tide level, by giving the most fertile land (polders) in Europe back to the sea. How do you think that feels for the farmers in that polder, that cultivated that land during centuries.

You wonder what a tipping point is? Well that's one, irreversibly giving back a polder to the sea, is an irreversible act to survive increasing high tides. At that level the tipping point has been passed.

Is this due to increasing CO2 mixing ratio's in the atmosphere? In the low countries we don't wait till scientists definitively prove, that climate is governed by atmospheric temperature and cloud formation dynamics, hence ocean dynamics and hence CO2 mixing ratio's.

Thanks for your understanding. We managed to stay above high tides, we will do it again. But the polders may disappear one by one along the Schelde river. Let's hope that at the end of this process there are still some left to live from for the Benelux countries.

Cheers,

Frank

Dear Frank,

I agree we measure and we see changes. but our knowledge of reasons why is limited. the question was about 398 ppm over a tipping point. I'm not pretty sure the coastal problems are maily regulated by the simple equation more CO2 more Sea level rise via increase in global temperature.

Http://iopscience.iop.org/1748-9326/9/4/045004/pdf/1748-9326_9_4_045004.pdf

as an example of previous lack in the knowledge (a very recent paper)

Dear Teodoro

Your statement that changes are measured but the knowledge of reasons is limited is too general. The knowledge about the components of current sea level rise is rather solid. We know that thermal expansion of the ocean water plays an important role and the respective evidences are more than independent single observations. The mechanism of thermal expansion is highly consistent with observed changes in sea surface temperature, ocean heat content and sea level rise. Also the contribution of fresh water input is consistent with the data on reduction of land ice cover.

It falls short of the scientific instruments at hand to treat these causal links in the same way as the many missing pieces in the general puzzle. For sure there are many things to learn e.g. about the influence of ocean currents on regional variability in sea levels. But does the further progress in understanding have a reasonable potential to negate the explanations of some main processes actually going on within the earth system that are already well established?

The IPCC expressed high confidence that these trends will be perpetuated into the future. However, this does not mean that the quantitative trend is very well known - see the model uncertainty ranges for every single scenario.

In conclusion, stating the ever lasting truth that there are and will always be many causal links we do not yet understand, is flat-ironing the current state of understanding and it's relevance for the perception of upcoming challenges to human societies.

Just leave room for doubts.

Currently the maximum ML measurement is 402 ppmv....stated to be the highest mixing ratio in 800,000 years.

It doesn't matter how much we try to mitigate, its gone too far. We have to focus on adapting to our new environment, or face the consequences of our actions unprepared.

Also, there is little point building up on land that is undergoing isostatic rebound or Isostatic subsidence. Its not just as simple as saying all sea levels will increase, there is soo much more to it than that.

This tweet might help:

Pumping Carbon: The United Nation’s Plan B to fix our climate

bit.ly/1m2xhoK @JohnSodeau #ntfm

don't forget that its CO2-equivalent that matters. With the recent and correct revision by the latest IPCC process of the global warming potential (GWP) of methane the total CO2-e is now about 435 ppm . While we don't know about "tipping" points related to CO2-e concentration, what this does mean is that our stablization window has now likely slipped to above 550 ppm.

So yes we have blown the MITIGATION window (this should have started around 1990) and are clearly in adaptation phase. We haven't prevented squat to date

"The present concentration of CO2 in Earth's atmosphere is the highest in the past 800,000 years and likely the highest in the past 20 million years."

http://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth%27s_atmosphere

Whether we are past the tipping point is a mute point, given how hard we are hitting the CO2/CH4 accelerator, wherever that point is, we'll be blasting past it (or have already). A year-and-a-half ago the estimate was for ~1,200 new coal-fired plants proposed globally, not sure if we are ahead or behind that, but either way, Earth's life-support-system will be very different from the temperate one we've been so fortunate to come of age in.

http://www.wri.org/publication/global-coal-risk-assessment

We either drastically change our consumptive behavior or it will be changed for us and not so temperately.

Is the tipping point we are talking about the part where temperatures start going down again? Global temperatures have been effectively constant for the past 15 years, in stark contrast to the predictions of the various global circulation models (GCMs).

I always had this quaint idea that science was based on verifiable physical facts, in respect of which a hypothesis was advanced to explain those facts. That hypothesis would stand or fall on its ability to explain and predict further facts. To make a claim that 'the science is settled' in some area would have been regarded as ludicrous presumption no so long ago. Or as someone once said, if it's science it isn't settled, and if it's settled it isn't science. It may be politics, it may be fashion, it may be religion, but science it is not.

We would appear to be so eager to accept the 'settled science' of anthropogenic climate change that all observation are somehow fitted into this intellectual straitjacket. Whereas a true scientists would say, "the GCM simulations show rising temperatures where there are none, so there must be something wrong with our models", the fashion nowadays seems to be to say "Yes, I know the data isn't in accordance with our predictions at present, but just wait a few years and the climate is bound to fall into line with them". This is not science, it is simply arrogance.

Recall the blind men and the elephant story:

http://en.wikipedia.org/wiki/Blind_men_and_an_elephant

The overwhelming preponderance of climate scientists recognize we have a serious problem on our hands, self-inflicted. Being selective about what part of the data one might consider in isolation, does not change the larger reality. "Ninety-seven percent of climate scientists agree that climate-warming trends over the past century are very likely due to human activities,and most of the leading scientific organizations worldwide have issued public statements endorsing this position."

http://climate.nasa.gov/scientific-consensus

Roger,

There are options, such as low regret, no regret and win-win adaptation measures that provide benefits even with a constant climate. So regardless who is right, you or 97% of climate scientists, there are policies that can be implemented. What's the excuse for not doing so?

Unfortunately there remain considerable confusion and over simplification regarding what global climate change would actually look like. In brief,

1. Global climate change expressed mostly in terms of "warming" has always been scientifically flawed.

2. The climate system results from the interaction between the surface ocean and the at atmosphere as they are one, coupled thermodynamic system involving two fluid reservoirs of vastly different densities (oceans are 850 times the mean density of the atmosphere).

3. Local weather is determine by the current structure of planetary vorticity (Rossby Waves) - in more lay terms, this means the jet stream pattern and where your

positioned with respect to a ridge or a through. Global climate CHANGE then is a manifestation of disruptions of traditional seasonal jet stream patterns - this means your local weather becomes more volatile, polar vortex intrusions and all of that.

4. Increasing climate volatility is then the signature of global climate change - in my view - and that can be easily supported by actual climate data. I would say that this increase started in earnest around 2010. I eventually will write a white paper on all of this.

5. If you just want to use "warming" as evidence then the issue is less clear, although increased warming in the Arctic is absolutely clear and that's a direct and simple prediction for any increased forcing factor on a rotating planet such that heat flows from the equator to the poles.

some of this material can be found at

http://homework.uoregon.edu/pub/class/atm

Unfortunately, no meaningful adaptation without mitigation is possible...

No tipping point reached at the moment, we (the nations and the people of planet Earth) still have about 15 years to work very intensely on decarbonizing the economy and the energy system connected. A number of measures have to be taken and must be taken very urgently: defining a maximum free carbon emission allowance per capita and *tax* progressively the rest. Taxes will be used to promote green jobs, tripling renewable power installed, efficiency measures (housing and transport mainly), phasing out of dirty coal power stations. My educated guess is that the free allowance will turn out to be in the order of 2 tons co2 eq per year, allowing some economic growth in Africa and at the same time slowing down the current 2 ppm/year rise and eventually stabilize CO2 concentration within 2050). At the same time we need an adaptation effort, as anyway we are going to face and survive a tough but hopefully not lethal new climate. Earth 2.0 is coming, and it rocks.

One little fact that I find interesting with regard to CO2 concentrations is that commercial greenhouse operators run their greenhouses at around 1000 ppm CO2, because this is optimal for plant growth. (Typically this is done by allowing the exhaust from propane heaters to blow through the greenhouses once or twice a day.) This strikes me as an indication that the plants grown in these places may have evolved in CO2 concentrations at this level. In other words, CO2 levels millions of years in the past may well have been much higher than they are today.

On the same topic, if by some magical means we were able to reduce the atmospheric CO2 level to 280 ppm, the result would be mass starvation, because plant growth rates at this level would almost certainly be too low to grow enough food for 7 billion people. See, for example:

"Effects of low and elevated CO2 partial pressures on growth and reproduction of Arabidopsis thaliana from different elevations", J.K. Ward & B.R. Strain, Plant, Cell and Environment (1997), vol 20, pp.254-260

Even starting from a different point of view I agree with Vittorio Marletto about the necessity of decarbonification of our model of development. And about 97% of consensus a very recent survey conducted by AMS showed very different results...it is just a myth that number.. About models, they show they do not work properly because they are not capable to reproduce the real world and because of that modellers introduced strange physical concepts such as the already cited 'missing heat', the only duty of a model is to reproduce reality if it does not do so should be considered 'out of order'

Teodoro, I agree with you about the 97% being a myth. The number comes from a 2008 Masters thesis at the University of Illinois. A survey of attitudes towards global warming was sent out to 10,257 individuals. A total of 3146 responses were received. Since, presumably, the desired responses were not received, a subset of 77 individuals who self-identified as climate scientists were extracted, of whom 75 agreed that human activity was the major cause of global warming. 75 out of 77 gives us the 97% figure. However, the true figure should be 75 out of 3146, or 2%.

There are two further problems with this figure. The first is that the term climate scientist was not in general use twenty years ago, and I suspect that anyone who self-identifies themselves as such is already a committed believer in AGW, thus ensuring the desired survey result. The second problem is that the individuals were selected for the survey based on the institution that employed them, without any regard for the nature of their academic qualifications, if any.

You can see a fuller description of this at:

opinion.financialpost.com/2011/01/03/lawrence-solomon-97-cooked-stats/

A lot of these times, discussions like this focus on absolute numbers rather

than the more physically relevant issue of RATES.

Yes in the past the CO2 concentration has been higher (snowball earth recovery probably requires > 1000 ppm from vulcanism) but this is not the issue - nor should there be an disagreement about absolute ppm concentrations.

What I think is relevant is that fossil fuel burning has produced an amplitude of change of CO2 concentration in about 100 years, whereas the ice age timescale

to produce a similar change is 10,000 years. This is not a benign or benevolent gift to either the Earth or humanity. Human activities accelerate natural rates - in the short term this might even bee beneficial, but certainly not in the long term as the Earth system if forced to find a new equilibrium. This is completely clear in the ocean heat content measurements.

I agree that the earlier "warming" period rate is similar. But I am talking about the rate of CO2 buildup - as stated earlier, I don't equate that directly to a warming response.

One other point, cilmate/weather is not annual, its seasonal - here is a treatment of climate data using monthly anomalies and not annual ones.

http://theenergycollective.com/wattheadguest/29150/global-temperature-continues-rise-primer-climate-baseline-instablity

G., thank you for that informative article, which sheds a new light on temperature variations. However, what it does not do is demonstrate that any of this variation is due to human activities. Please note that I do not categorically deny any human involvement in this temperature increase, I merely say the case is not proven.

If we go back to the 1st IPCC report, i.e. prior to the hockey-stick graph, and look at the 1000-year climate record given there:

it clearly shows a recovery from the little ice age, but not, as of the 1990 date of this report, anywhere near the maximum shown in the medieval warm period. Since one may reasonably say that the medieval warm period occurred with little or no human influence, I see no compelling reason to ascribe any significant human influence to the current warming. As you point out in your article, climate is a noisy signal, so extracting a human-induced component from the climate record will require a very good knowledge of the forces responsible for climate change in the absence of any human effects. I do not believe we have that knowledge at this time.

Exactly, at the moment we do not have the knowledge to firmly state that. It is not a matter of deny. Just the body of proofs it is not sufficient and models do not demonstrate the capability to reproduce reality. models reproduce the past only because they have been created that way.

To answer a couple of things

1) The data comes from the National Climatic Data Center - all our ground based measurements using the Historical Climate Network (HCN) mostly.

2) In the monthly anomalies the baseline is 1900-2000

3) I don't equate climate change with a direct short time scale warming. The Marcott and Anderson quotes, I believe are likely physically correct but on time scales

of 50-100 years. I think the shorter timescale response of the Earth system is, as said before, a) increasing climate volatility and b) systematic warming in the polar regions (mostly Northern Hemisphere). Systematic global warming will take a longer timescale to be established because of the high variance in the global climate

system.

4)/ To R. Graves my response to this issue has always been this:

a) I can not scientifically prove that human activities are the cause of any climate change

b) actual evidence for climate change does not have high signal-to-noise

c) If argued this case in a court of Law, I believe it would be won based on the "preponderance of evidence"

d) there is no question and no scientific question, that the accelerated rates of change in the Arctic are not natural.

e) Much change and much improved signal has originated over the last 10 years. Its very important to use as up to date data as possible as now measurements indicate rapid increasing of ocean heat content. - This is what the combined activities of humans have done.

Levitus etal 2012 is THE source on this

http://onlinelibrary.wiley.com/doi/10.1029/2012GL051106/abstract

I am not going to engage in a lengthy debate in this forum about baselines, temperature data and the like.

Will just summarize my view (which could be wrong)

1. Just using average temperature data alone does not build a strong case. I completely agree and I agree there are calibration zero point uncertainties. Climate is not about just average temperatures.

2. The calibrated ocean heat content measurements are the most direct way to measure human inputs and that rise is alarming (and that is what drives the

global climate system).

3. The rapid changes (over the last 5 years) in Arctic sea ice melting as well as the methane releases from Siberian permafrost (first detected in 2010) are unprecedented rates of change.

And the actual recovery is unprecedented even in increasing CO2 concentration.

I do not want also a lengthly debate but there is something missing in our knowledge.

G., with regard to rapid changes in Arctic sea ice melting, the data is equally supportive of an approximately 70-year freeze/thaw cycle in the Arctic, and we just happen to be approaching the peak of the thaw at this time. There is a well-documented thaw beginning about 1920 (see docs.lib.noaa.gov/rescue/mwr/050/mwr-050-11-0589a.pdf), and the Arctic Ocean was navigable in the 1940's (just google the phrase 'RCMP schooner St Roch' for details). There is an equally well-documented freeze-up in the period 1960-1990, and another thaw beginning around 1990. This suggests to me a 70-year cycle, in which case we can look to a further freeze-up beginning about 2030.

It may be, of course, that the rate of thawing is greater today than at the corresponding point in the last cycle, say around 1944, but I am unaware of any reliable data to confirm this.

One other point on which I can only hypothesize at this time is that the Antarctic may also follow a 70-year cycle, but in antiphase to the Arctic cycle. As we know, the extent of Antarctic ice is currently the greatest since measurements began in 1979. How this mechanism would work I have no idea, but it seems to be an avenue of research worth pursuing.

I am aware of previous cycles and data that support them. I believe energy input from human activities is now accelerating natural cycles. I don't think anyone can dispute the fact that the energy output from the human activities is now significantly higher than it was in the 1940s so whatever nature is doing with its cycles, the extra stress of the human dimension is growing. I don't think that stress is benign.

A good and important question. In view of palaeoclimatology, tipping points or abrupt changes were more likely to occur in glacial or deglacial stages in late Quaternary. It seems that, in a warming world, the climate is more or less stable. This might have been related to the lack of the big ice sheets over North America in inter-glacial periods, an important boundary condition to the slowdown or disappear of the thermohaline.

Let's not forget about the GIANT buffer the ocean is, it produces a large lag time (50-100 years) between emissions and atmospheric response. In my view, we have now recently emerged from this buffer as the oceans capacity to store this extra heat

has been saturated since around 1990. If you want to consume nature as fast as possible for economic reasons then that is just fine - there just is an eventual price that some generation pays for that decision.

We may even yet be underestimating the size of this buffer, all 1.37 billion cubic km of it. I have yet to see a convincing explanation of why some or all of the current atmospheric CO2 content is not a result of ocean outgassing as it warms up after the little ice age, which only ended a little more than 150 years ago. I have certainly seen many explanations of why it can't be natural outgassing, but none that I consider truly convincing.

Another reason why I think ocean outgassing may be a significant factor is Henry's law, which deals with the equilibrium between gases dissolved in a liquid and in the atmosphere above the liquid. Since the concentration of CO2 in the upper layers of the oceans is about 120 times that of the atmosphere, Henry's law says that any additional CO2 introduced into the atmosphere should be absorbed a lot faster than appears to be the case. The only way I can see that this could be accounted for is if ocean outgassing is occurring at much the same rate as excess CO2 is being absorbed by the oceans.

It seems reasonably well known from Ice Core data that the natural increases of CO2 at the 100 ppm level occur somewhere in the time regime of 10000-20000 years (although there is some data consistent with maybe 5000 years).

Its taken about 120 years to add the most recent 100 ppm.

http://www.skepticalscience.com/pics/HistSummerArcticSeaIceExtent.jpg

Seems to be the most reliable representation of average Arctic Ice Extent over the summer months over more than 100 year baseline. Note this representation is not MINIMUM sea ice extent, which is the usual representation, but rather represents

the average summer time area of the artic covered by ice. You would have to source the original article (Walsh and Chapman 2001) to determine the methods used for this data reconstruction. Also, the solid line is a crap fit to the data - yeah mathematically you can fit a polynomial but that's also the wrong function for

this kind of stuff - a damped exponential, scientifically more valid, is also a good

representation.

This waveform, I believe

a) confirms earlier statements about unprecedented rates of change

b) shows the 1940s event as very brief in time and that even seems to rebound into a positive feature ice mass increases until about 1955 - after that one sees systematic loss of ice at accelerating rates

c) this data stop at 2011 I think and don't include the extreme 2012 and 2013 points

Its difficult to believe that there is anything natural about this waveform. It's easy for me to believe that the Arctic is the most sensitive indicator of increasing ocean heat content.

There are fundamental unknown pieces in the tipping point puzzle. How do we wish to define the "tipping point"? What would make the level of CO2 a tipping point in that sense? What would we measure? As far as the ocean, clearly there is a limit for what the ocean can buffer, and while we would like to think of the whole ocean as a buffer, it won't be.Sure, eventually the loss of all shallow water carbonate sediments, but for the deep ocean it is not going to happen as fast. The surface ocean will reach a maximum saturation, if it has not already. Even "recovery" will not happen fast. If you use the PETM when CO2 reached 800ppm as a model; the "event" lasted 200,000 years.and the comment by Ken Towe is right on: The level of CO2 in the atmosphere is not going to go down in the near future, even if we stopped all addition of fossil fuel carbon dioxide. The rate of addition might slow if we convince the 7 billion people they don't want the lifestyle of higher energy consumption.

and the level of methane will continue to rise independent of Carbon policy

Indeed, methane production will increase even more with the warming of gas hydrates that are all over the Arctic There is strong evidence right now of seabed methane loss from studies of off Svalbard Island (published in Science about a year ago).

Ken, the graph of CO2 versus population would certainly seem to argue some kind of a relationship, but which is cause and which is effect? One possibility is that the more us us there are, the more CO2 we generate. However, another possibility is that more CO2 = enhanced crop yields = more food = more people. In support of this latter relationship I would argue that most of the population growth in the last 50 years has occurred in countries in which infant mortality rates were high due to lack of adequate nourishment, so if you increase the food supply you will lower the infant mortality rate, and hence increase the population.

Of course, following this argument, if by some superhuman efforts we manage to reduce the CO2 level to, say, 350 ppm, we can expect to see a dramatic rise in infant mortality rates again.

Hi Roger and Ken,

In statistical mathematics, when you graph a variable y as the ordinate and x as the abscissa, one implicitely accepts that:

y=f(x).

Hence what about:

[CO2] = f(Np)

where [CO2] is the mean global CO2 mixing ratio in ppm and Np is global mean global population density in [SUM(global humans)]/[km² life sustaining continental surface].

Or do we interpret this relationship without statistical inference?

Cheers,

Frank

well CO2 buildup on an annual basis is of course the difference between sources and sinks. Both the sources and sink rates change with time and both may correlate with Np

there is no urbanization in the Arctic :)

yes I agree that subtracting out the urban signal has not been done well.

We have a paper on this about to be submitted using 137 climate locations

in the American NorthEast which have 100 years worth of data. The urban

signal is clear and its contamination to the rural areas is also clear. One

of the many reasons why LAND air temperatures are one of the worst diagnostics (but, of course, the most widely used).

Kenneth,

Since the beginning of the 'cold' war (what's in a word no?) the Russians have gathered an impressive dataset of the thickness of the arctic ice sheet. They didn't do that for scientific objectives. No, they gathered these data to know when they could pop up through the ice sheet, with their nine operational atomic powered and atomic rocket equipped giant subs. Eventually the US Marine has the same type of record, because they have the same type of submarines and a shot at Russia from the Arctic after penetrating the ice sheet would be a quite nice kick in the ass, when the Russians would get it in their mind to start launching their rockets first. Or the US ? Nothing is certain when tensions would start building up again between the US and Russia.

Anyhow, what do these records show, well that within a few years from now, the US or Russian subs can launch their rockets without having to come up through the ice sheet. It simply won't be their any more during summer. Climate change is quite convenient to kick-off a large scale nuclear war from the Arctic. Everything around the Arctic will be within reach for the subs to launch their intercontinental nuke rockets, Russia, Canada, the US and Europe. A wet dream for every offensive military nuthead, whther Russian or US. And climate change will be quite prominent after enough nuclear blasts blasts. Could even kick-off the next ice age depending on the amount of dust injected in the stratosphere.

Now seriously. The Russian measurements show a steady-decline of the Arctic ice sheet and especially its thickness over the last 25 years. My dear colleagues, this has been meticously measured by the Russian marines. These are not results from GCM's whatsoever.

With some simple statistics the Russians could even predict when the Arctic ice sheet would disappear altogether during summer, opening an arctic circumfering shipping lane, opening up the access to natural resources which have been inaccessible during centuries.

It is known that the Russians have and sell a lot of natural resources to Europe and China. When you look at the stretch Siberian territory along the Arctic, for sure their resources will increase significantly the coming years.

Moreover the Russian and US marine, will be be able to come up through the arctic ice sheet even during winter, because the subs silently moving around underseas penetrate through 5 meters of ice like through a piece of cake. No sweat.

It seems as if a a 'Brave New World' is opening up with the disappearance of the Arctic ice sheet Kenneth. Do you like its new possibilities offered? Or are you not impressed?

One thing s for sure, there are no big cities around to heat up the Arctic atmosphere. So how do we explain the meltdown of the Arctic ice sheet as measured by the Russian (sub)marines as well as the new trans-Siberian shipping lane which opened up without ice breakers since the summer of 2012.

Cheers,

Frank

Hi Kenneth,

I already saw this,

https://www.youtube.com/watch?v=UxB11eAl-YE&list=PLfmbsPhL3ZvhCuM6O3pI2-T7oYEY0JSpK

Pretty much the same, but live.

And something about Russian capacity

http://rt.com/news/russia-severodvinsk-nuclear-submarine-036/

and

https://www.youtube.com/watch?v=EKyRXYmZQSA

All very deadly indeed. Count on it that Russias increasing energy resources will bring in a lot of additional Roebels from China and Europe (former Eastern Europe) mainly, which will be invested again in this rather subsurface arms race once more.

I sincerely hope that all this weaponry will never be used.

No?

Cheers,

Frank

Much of this "debate" on the arctic, early warming periods, etc can be found here

http://judithcurry.com/2013/04/10/historic-variations-in-arctic-sea-ice-part-ii-1920-1950/

or just google on Judith Curry Arctic Ice and find lots of stuff

I have already provided my assessment. The changes that are happening in the arctic the last 5 years are unprecedented and the rate of change is alarming. That assessment could be wrong. 10-20 years from now we will all know.

The major result from the American Northeast is an extremely strong summer time signal of combined warmer and wetter summers - consistent with the water vapor feedback loop due to increasing deep tropical convection as the ocean dissipates its heat.

As I have said before, I don't think that ANNUAL temperature analysis tells you very much and that climate change is not just temperature.

I think I am finished with this dialog

I am not talking about temperatures at all but you keep coming

back with temperature trends.

I am talking about the combined rate of loss of Arctic Ice, the rate of increase of

permafrost methane leakage (mostly from Siberia) and the rate of ocean heat increase, and the various Extreme Ice (Jason Box) measurements (including Greenland). I think these are alarming trends in the cryosphere and since the Antarctic is a much much different physical land+ice mass than the Arctic, I don't think that is much of an indicator of change. I think the Arctic is, I think we are being warned and I think we are ignoring it.

Book your cruise line now to go Visit Santa, in September, sometime likely in the next decade.

Kenneth,

You are so close we should meet to do this over coffee. I agree that energy is not the enemy, we want more energy and as cheap and plentiful as possible. Energy lifts people from poverty, fights disease, provides clean water and sanitation and enables education. We need more! The problem is that we have not yet learned to disassociate the production of energy from the the release of greenhouse gases.

You must know that climate scientists are aware of the urban heating effect? Thanks to Anthony Watts and others, far too much attention was spent frying that old canard. It is real, it has an effect, it does not change the overall pattern of warming or conclusion of that research. Microclimates matter. But not globally.

The global warming we see today should not be taken out of context. Anyone who studies climate science recognizes the strong decadal influence of ocean-atmosphere cycles such as the NAO/AMO because they have a major impact on regional climate, but they vary temperature around a mean, and can not drive the multi decadal trend in global temperature that we recognize in both the atmosphere and in the oceans.

As geologists, you and I know that climate has changed in the past, but all the natural forces that have affected climate in the past are now pushing global climate to cool, not warm (as we might more realistically expect from the geological record). The only factors acting to force global climate along the observed long-term warming trend are the concentration of greenhouse gases and strong positive climate feedback. This statistical link between greenhouse gases and global temperature is hard to refute; as is the basic physics/science.

As for the Arctic, everyone I know or talk to is well aware of the regional Arctic warming that took place in the 1930s, but I am not aware of any peer reviewed publication that suggests that this was more than regional warming. I am intrigued that you place so much emphasis on old and incomplete data from the 1930s but (seemingly) ignore the broader context of the current warming and the extensive satellite and other data that underly the conclusions of NOAA/NASA/IPCC/Met Office… heck, even Richard Muller! From the 1930s ice records I see no evidence of significant long-term loss of ice volume. I see little evidence of any major lasting impact on ice at all. It is particularly important to note that the pattern of global warming that parallels Arctic warming is fundamentally different from that observed during the 1930’s. Warming of the Arctic in the 1930s was localized and mostly on land. The warming we see today is on land and ocean, with a spatial and temporal pattern that is very different (more widespread) from what we can glean from the limited data of the 1930s.

As for the AMO, its role is increasingly (not perfectly) understood but nevertheless successfully reproduced- along with Arctic warming- by climate modeling. Warming in the 1930s and today are clearly not simple expressions of a natural AMO.

As for the old canard of warming in North America, well, who cares? It is such a small part of Earth’s surface that we might expect to be hard put to find conclusive evidence (although in my and others opinion there is plenty of evidence). When 90% of excess solar energy goes into the oceans we would be crazy just to look to the atmosphere for an indication of warming. The oceans continue to rise due to thermal expansion, melting of ice adds to sea level, acidification continues apace. There is lots of evidence that global (land+ocean) temperature is still increasing, in fact it may even more extreme than we thought because we have consistently underestimated Arctic warming. Every decade this century has been warmer than the previous one.

I am also a geologist, so I understand a geological climate perspective better than most. Past climates have been warmer and life has flourished, but rarely has climate changed so rapidly-as it is now doing- so that ecosystems have insufficient time to cope/adapt/evolve. When this has happened in the past (as you well know), the outcomes have not been positive for prevailing ecosystems! I think we should be worried about tipping points. It is not the change that matters, it is the rate of change.

We can let this go, by all means, but not on the understanding that there is some kind of balance between these arguments. There is no such balance. You opinions are clearly contrary to the vast majority of our peers. I accept this does not mean you are wrong, it may well be that you are correct and I am the simple sucker for being taken in, but if you really believe what you write- and can prove it- there has never been a more important time to publish- and I see you have an impressive record. These days I am a meager writer and teacher, so I recognize and respect your interest in these issues, there can be few issues more important than this one.

Kenneth

I want to leave the climate change question (e.g. how many “regions" do we need to be affected before it becomes global) to address the issues your raised about population and poverty as they relate to tipping points. It sounds to me like you would appreciate the text I wrote for Pearson (Global Climate Change-turning Knowledge into Action, because I make many of these points (order an inspection copy).

We in the developed world have no right to ask the developing world to reduce the rate of economic growth and the growth of prosperity because that is what is saving tens of thousands of lives… many of them children and the elderly. However the paradox is that these same groups are under greatest threat from the impact of sudden/rapid climate change and pollution from the use of fossil fuels.

This is a big dilemma. If we accept that the developing world has little choice but to exploit fossil fuels, our primary role should be to encourage greater efficient energy production and transmission and the conservation of energy where possible. Our secondary role should be to reduce our own emissions as much as possible in order to limit the impact on climate, reduce the probability of a "tipping point" while not undermining our global industrial competitiveness or energy/national security- we do not want to put jobs and lives at greater risk.

Unlike you, I do not believe that we should just wait for future technological solutions. I believe there is much we can do to improve our lives here in the USA and also enrich the lives and of those living under the threat of climate change overseas.

Our move to natural gas already has us on track to reduce GHG emissions by 20% by 2020. The free market did more to undermine coal than any environmentalist group. The use more clean energy such as solar, wind (I prefer offshore), tidal, small hydro, biofuels (NOT corn) can make a growing contribution to replace coal… and create new jobs and in a growing export market. More emphasis on energy conservation and efficiency, smart grids that get energy where it is needed when it is needed… all these things add value to our economy and encourage innovation and entrepreneurship. I even go as far a suggesting that we need to invest more in nuclear, especially new micro generators). As far as I am concerned we need to replace coal when we can. It is dirty, causes pollution when both mined and burned and remains a major threat to public health (North Carolina/West Virginia just recently for example).

The answer to climate change is "focused capitalism", not big government. Government has a role. Tax relief and subsidies help, investment in research is imperative, and regulation and inspection are legitimate. We just need to find a balance between what is necessary and what is so intrusive that it stifles innovation. No regulation would be a disaster, but too much can stop us getting where we need to be.

If we do not do these things, we will lose out badly to China, India, Brazil the EU and Mexico in a growing clean energy mega market. Rapid climate change with population movement and water shortages (for example) increase the risk of conflict overseas and thus threaten our national security. Moving away from oil for transport and coal for electricity not only enhances the (especially urban) environment but also reduces our dependency on imports and enhances energy security (did you know that imports of coal increased by 230% since 1999).

And if it is all just hype? … If tipping points are not a real threat? Well, we are left with a more secure nation, creating new high tech and high paying jobs, and an economy that is more competitive and more secure than it was before. All for the cost of around 1% of GDP. That is a lot… but two recent wars and a string of climate-related disasters puts that into perspective. We need to do these things and more, not for the good of the world alone, but because they meet our own global strategic interests. OK... I am done now :-)

Nice to meet in any case! thanks for the question Jeff!

Our trajectory on climate change began over 15,000 years ago with the use

of fire to drive animals off cliffs, and the use of the stone axe to cut down

trees. Between 12,000 and 8,000 years ago, the continental ice sheets

melted, the ocean levels rose 120 meters (400 ft ), and the entire atmosphere

moved upward compared to the land surface which in effect moved downward.

The effect was small, but the gradual increase in the trend toward a warmer

planets is very old. Around 1700 we began to be able to

measure the effects of change, and record them for posterity ( The

British Admiralty ). The trend has not abated. Back then the CO2 was around

280 PPM, and the Atmosphere was standardized in a pressure of

100,000 Pascals, which by 1976 was restandardized at 101325 Pascals.

Notice the upward trend, or increase in the Atmospheric Pressure of

about 1.325 Percent in a mere 276 years.

In the 1700's rivers regularly froze over solid in winter, but by 1720 that was no

longer happening in some places, and the consumption of coal was

already increasing, and the use of Locomotives was underway.

In the last 340 years the CO2 has climbed from 280 PPM to roughly 400 PPM,

and the trend is and will continue. It is an accelerating problem with

an accelerating trajectory.

The Earth has had high CO2 continents in the past, but the changes were far more gradual. Even if we could dramatically change how we produce both

power and energy for transportation, the trajectory will continue to rise,

for hundreds of years.

Kenneth... that is why we have satellites and ocean buoys today that tell us a different story about ocean temperate both above and below 700m. I am sure you could be right about Darwin.There are lots of places in the world that have not warmed... some have even cooled and who knows that the PDO/AMO etc were doing at the time. We talked about this before and I am not arguing. I agree that the concept of global temperature is strange. I prefer to think about global heat content... and that is increasing rapidly- and that is why we worry about tipping points as these appear in many dynamic systems that are displaced rapidly from equilibrium. I do agree with you about population... the paradox you point to is that the best solution for population growth (historically) is economic growth. To get economic growth we need energy... oops... But no one I know of is suggesting that we limit access to energy in the developing world. I do hear that we should work on conservation and efficiency and leapfrogging to technologies that minimize emissions intensity, while we in the developed world work to reduce base -line emissions by using gas and nuclear as a transition towards the use of cleaner energy in the future. All the time creating good, well paid jobs, cleaning the environment, boosting exports, reducing imports, securing energy and removing our strategic national interest from conflict zones. Not a bad deal?

I can answer the science questions...how to heard cats is beyond me!

I would not expect there to be any significant temperature differences

with time over the surface of the Oceans due to the enormous volume

of the Oceans, and its density and specific heat. In fact I would not

be surprised that the change in temperature of the Oceans would take

thousands, if not millions of years to gradually catch up to the changes in the

temperatures of the Atmosphere that occur in the middle of continents.

I played with some numbers, and graphed the recovery time to

get the micro-organisms to recover their full rate of deposition

in what is now two locations in Norway where Chalk deposits

were deposited. Following the impact event at 65 million years ago,

the rate of deposition of Chalk in two locations in Norway took

240,000 years to reach about an 80% level of the prior rate of chalk

deposition, and 265,000 years to reach a fully comparable rate of

deposition of chalk.

In contrast, the rate of deposition of micro-organisms in one location,

before, during, and after the Impact event was essentially unchanged

in Antarctica.

This suggests to me that either temperature changes, or flow pattern

changes , or both were very much influenced by the Impact off the

Coast of Yucatan, but not hardly influenced at all where oceans surround

Antarctica.

If something changes suddenly, it can take a very long time to recover,

so by inference, if something changes gradually, it can take a very long time

for those changes to propagate through all of Earth's Mass systems.

We will see the changes first in the thinner and lighter mass systems

of the Atmosphere, and see the other changes in the more massive

systems ( Water and Land, and Ice ) more gradually.

From the geological perspective of deep-time, the last few tens of thousands of years, and the last few millions of years, may have seen the absolutely lowest CO2 levels in the atmosphere ever thought to have existed on Earth. Models estimate the CO2 values back in time, using various proxies, with varying degrees of precision, and there is large disagreement. However, there is almost no argument about the relative levels being much higher in the past. The attached chart of Phanerozoic CO2 levels shows this really nicely. If these various models are correct, and we are at a low stand in the atmospheric CO2, then it is not surprising that future levels may rise. This 'observation' completely avoids the issues of cause and effect, but does offer hope for the Earth that no matter what CO2 levels rise to, life will flourish, as for example in the 'dinosaur-friendly' Cretaceous period ("K"), when atmospheric CO2 may have been as high as 1000 to 2000 ppm (thats nearly 5 times current day values). It has been suggested that the big dip near 300 million years ago (P-C; Permian Carboniferous) could reflect both longterm burial of organic carbon, and/or the time lag between subduction into the mantle of the first major shelf carbonates since their first dominance in the earlier palaeozoic at >500 m.a. Society's concern about climate and CO2 has highlighted our sublime ignorance about the behaviour of carbon on the Earth since its formation. This is now attracting a growing amount of interest, amongst diverse scientists who are keen to combine their skills to examine how fluxes of carbon between different deep reservoirs may have connected with the Earths surface and the air we now breath (*http://deepcarbon.net/).

Adrian, very interesting contribution. However, I think that the concern about increasing CO2 levels (and derived impacts) is not about the future of life on Earth (which I am pretty sure it will continue with or without humans) but about the future of life as we know it...

A couple of questions come to my mind regarding your chart. It shows the changes during the Phanerozoic (542 million years) and you mention that "if models are correct, it is not surprising if CO2 levels rise". The first question is regarding "cause-effects". Why did it go down? Why did it increase during the Jurassic? The second question is regarding the rate of change. Is it "normal" that the change happens in 100 years, which in geologic time is almost nothing?

The CO2 cycle is indeed complex. CO2 can rise due to the impact of volcanism and then as feedback as the oceans and terrestrial ecosystems warm. It falls when volcanism eases, the oceans cool, ecosystems store more than they release and at times when erosion rates increase during periods of orogeny. The details are complex, but these main drivers explain most of the changes we see in the geological record. That is a start.

It is one of my personal mantras that climate change is not the enemy. For most of Earth history is has been warmer and life was even more abundant and diverse than it is today. But the Permian and K-T, and even the PE Thermal Anomaly remind us that it is not climate change we should worry about, it is the RATE of climate change and the impact this will have on settlement and agriculture ... especially on poor communities, and on the natural environment. Tipping points (the subject of this discussion) are an imminent hazard that we need to take seriously and we must simply hope to avoid until we take the necessary action to mitigate their potential.

What I saw in hawaii was a lot of afternoon rain. This makes sense in that

more CO2, and more heat means more energy available to store more water

in the atmosphere, which releases more rain.

This was also the observation of some old time locals. More rain and it is

raining more on the dryer leeward side of the islands, which are deserts.

Kenneth, your observations on comparing the two 20th Century warming rates are very interesting, but the alert to population growth, makes stark reading. Simply putting demand for Earth resources and energy into future context is dominated by population growth, so that you might suppose that "green" sustainable options are likely to become overwhelmed by rising human numbers. For example you might consider that for an average 40 year old person today, the Earths population has ~doubled in their lifetime. To quote others, there has been more growth in population in the last fifty years than the previous 2 million years that humans have existed. However all is not gloom, and we are evolving into an increasingly technical race at perhaps a compensating pace. I would draw interested readers to a fine article written by environmental scientist Jesse Ausubel, winner of the 2014 Breakthrough Paradigm Award, who contends that human development is the liberator of the environment, and that our continued use of technology will allow us to construct an environment that is better for humans and better for biodiversity. Here is the link to his landmark paper:

http://phe.rockefeller.edu/Daedalus/Liberation/

Hi Adrian

Interesting paper from Jesse Ausubel. I'll read attentively.

Jesse seems to be a technological optimist (like many Americans).

I represent the anti-these.

Jesse looks at the possible progress to be made, I look at the risks we run.

But a primer indeed, nice work. But I will try to give feedback on aspects (possibly) lacking for example the role TA (Technology Assessment) is playing in his paper. I consider TA as a quite important activity, many don't.

Cheers,

Frank

To Kenneth Towe:

It would be Interesting for the Smithsonian Institution that is now involved with

" The Great Courses " to do a series on comparing Consensus Theories to

Unpopular Theories, and how the Consensus Theories delay the acceptance

of new Theories.

I have noticed that the Advances in Astronomical Telescopes have really

promoted New Theories in that Field, and their acceptance is moving at a

faster pace than other fields.

I suppose that funding for Climate Sciences would stagnate if everyone

accepted Climate Change as a Normal Earth Activity rather than as

something to worry about , and study, and fight.

One of the things that the Ausubel paper indicates is that the common factor in all human endeavour to improve the environment, whether in terms of climate (assuming this is within our capacity to change), or protection against the encroachment of the oceans, or the preservation of forests, and so on, is that it takes a lot of money. Nations have to be wealthy before they can undertake major projects such as building coastal defences in the Netherlands. However, in order to become wealthy, there seems to be an interim period in which a great deal of environmental degradation is produced. China is a good example of this. Over the last 40 years or so the Chinese economy has soared, and in doing so has created some of the worst atmospheric and general environmental pollution in the world. But now that China is becoming wealthy these problems are beginning to be addressed.

Conversely, poor countries are much more likely to create environmental degradation than rich countries. Zimbabwe is a case in point. When it was known as Rhodesia it was a major food producer and exporter. Today its GDP has plummeted and desertification is occurring because of poor farming practices.

I think we often fall into the trap of linearly extrapolating current conditions to predict future disasters without regard for the natural human tendency to improve the environment when the availability of wealth allows it. The use of terms such as ‘tipping point’ I find to be counter-productive because they engender a sense of helplessness which mitigates against this natural tendency to spend time and effort to improve matters. Writing about tipping points is a good way to get noticed in the media, but doesn’t seem to achieve much else.