This week sees the final round of preliminary talks on a new UN climate treaty before December's Copenhagen summit, where delegates seem to be focusing on emissions in 2020. Myles Allen argues that they must not lose sight of the much greater challenges that lie beyond 2020 or they risk wasting another decade in the battle against dangerous climate change.
On Thursday, 22 October 2009, a single tonne of anthracite coal was unveiled in the Science Museum in London as part of a new exhibition on climate change.
Not, you might think, anything particularly remarkable about that, except that this is not any old tonne of coal: it will be, as close as we can estimate it, the trillionth tonne of carbon to be released into the atmosphere as carbon dioxide since industrialisation began in the 18th Century.
The Science Museum, London, and University of Oxford are committed to looking after it for as long as it takes, and solemnly escorting it down to a power station or wherever it can be used most efficiently when total carbon emissions from human activity reach one trillion tonnes.
If, that is, that time ever comes.
The trillionth tonne matters because carbon dioxide accumulates in the atmosphere. Once released, it continues to influence the climate more or less indefinitely unless active measures are taken to scrub it out again, which is not something anyone knows how to do on any scale.
Over the past couple of decades, carbon dioxide emissions from fossil fuels have risen by an average of 1.6% per year
Emissions since 1750 comprise of just over half a trillion tonnes of carbon (you can keep track of the number, and the countdown to the release of the trillionth tonne, on the trillionthtonne.org website).
This is estimated to have caused just under 1C (1.8F) of global warming (other things affect global temperature as well but, as it happens, their effects more-or-less cancel out over this period).
So if we release another 500 billion tonnes, we commit the Earth to a most likely warming of about 2C, which is widely regarded as the threshold for dangerous climate change, and a rubicon that governments of G8 countries and other major economies pledged this year not to cross.
Over the past couple of decades, carbon dioxide emissions from fossil fuels have risen by an average of 1.6% per year, even allowing for the occasional blip like the collapse of the Soviet Union and this year's recession.
Emissions from deforestation have continued steadily.
If these trends continue, which is a relatively conservative "business-as-usual" scenario, we will release the trillionth tonne sometime in the 2040s - a date that is steadily advancing, as the underlying trend is for faster growth in recent years.
Worsening food security is likely to be one of the main impacts
So, will the Science Museum only have to look after this tonne of coal for less than 40 years?
That rather depends on what happens in the next 40 days, at the end of which the climate negotiations will be nearing their climax in Copenhagen.
This week's negotiations in Barcelona will go a long way to determining whether agreement is possible in Copenhagen - and if it is, what sort of agreement.
If governments are seriously committed to limiting global warming to less than 2C above pre-industrial temperatures, then must preserve the "trillionth tonne", not just until 2020 or 2050, but until the whole issue of climate change is ancient history.
Other emissions resulting from human activity are expected, on balance, to add to the warming effect of carbon dioxide in the future, so if we are to keep the overall warming to less than 2C (or, for that matter, retain any hope of carbon dioxide levels eventually recovering back down to 350 parts per million, or avoid dangerous levels of ocean acidity), we cannot afford to release the trillionth tonne, ever.
You could reduce your lifetime carbon footprint to zero and save the world from global warming
for less than two seconds
The longer we put off reducing emissions, the faster they will have to fall to stay within the same total - just as dithering before you leave the house pushes up the speed you need to pedal to make your appointment.
And eventually, if you dither long enough, you simply won't make it.
This is where the trillionth tonne could be useful, even in the next 40 days.
If your government's negotiators in Barcelona and Copenhagen claim they want to keep global warming below 2C, and the chances are that they do, then they should have a plan to prevent cumulative carbon dioxide emissions from exceeding a trillion tonnes of carbon.
If they don't, then they haven't thought it through, no matter what they claim emissions will be in 2020.
This matters, because many of the measures they might take (or, more likely, ask you to take) to reduce the rate of emissions in 2020 would have no effect on, or even increase, cumulative carbon dioxide emissions overall.
Act now or pay later
What can you do?
Clearly, reducing your carbon footprint helps. Emitting carbon more slowly buys time, which we will certainly need.
But to solve the problem in the long term, we need to reduce net emissions, in effect, to zero.
Campaigners say atmospheric carbon must not pass 350 parts per million
You can't do this on your own, no matter how heroic a consumer you are.
You could reduce your lifetime carbon footprint to zero - by making your home zero-carbon, never use a car and grow your own food - and save the world from dangerous climate change for just a mere two seconds.
So the most important thing you can do is make sure your government recognises the importance of cumulative carbon dioxide emissions in climate policy.
At a previous round of negotiations, in Bonn in June, a group of us presented an open letter to the negotiators urging them to acknowledge the need to limit cumulative emissions of carbon dioxide.
We did not call for a specific cap: just an acknowledgement that the principle would fundamentally alter the focus of future negotiations. The aim would no longer be to ration out emissions; the aim would be to ban them, just as we banned CFCs. We didn't save the ozone layer by rationing deodorant.
As far as we can tell, that request fell on deaf ears: "This was not the focus of the negotiations at present."
Odd, when cumulative emissions of carbon dioxide are the principal determinant of the risk of dangerous long-term human-induced climate change.
And next time you are in London, drop in to the Science Museum to pay your respects to the trillionth tonne.
Take your children. Explain to them that if it is still there for them to show their grandchildren, they will have achieved a lot in the fight against climate change - but not enough.
Only when their grandchildren are showing their grandchildren the trillionth tonne, still safely on display in the Science Museum in the mid-22nd-century, will this whole saga be passing into history.
And wish them luck.
Myles Allen heads the Climate Dynamics Group in the Department of Physics, Oxford University, and is the principal investigator of climateprediction.net
The Green Room is a series of opinion articles on environmental topics running weekly on the BBC News website
Do you agree with Myles Allen? Is it necessary for leaders to mandate emissions cuts now - or can the world wait? What do you realistically expect from the Copenhagen summit? Will the trillionth tonne ever be burnt?
President Obama has been president for 1 year, and just recently there has been news reports that he has lost popularity amoungst the American people. During this time, President Obama has been pushing for climatic awareness quite strongly. The reason President Obama has lost popularity is because many people in America are still without work, and they feel that he isn't doing enough about the economy. How can world leaders make the changes necessary to combat global warming, when the common people themselves don't care!! We all still value a strong ecomony more than the climate, it is the people that need to change, in order to allow world leaders the freedom to make the painful but necessary changes required to combat global warming.
Neil Simmons, Bangkok
Doubt at what the science says is often used as a reason not to change our behaviour. Whereas most scientists believe that uncertainty is a strong indicator for proceeding with caution. And that means not continuing 'full steam ahead' as if nothing could go wrong! Does anyone remember the Titanic?
The comment that CO2 only stays in the atmosphere for about seven years is a myth spread by the fossil-fuel industry and is based upon out-of date science. That this is untrue shown from the accumulation of CO2 in the atmosphere.
There is plenty of science that CO2 remains in the atmosphere for hundreds of years, perhaps millennia.
However studies of natural CO2 sequestration rates indicate that the removal of CO2 takes a phenomenally long time - many tens of thousands of years.
Don't take my word for it! Hansen et al. 2007 suggest that 22% CO2 remains after 500 years 19% after 1000 years (based upon Joos et al., 1996; Shine et al., 2005) Archer 2005 suggests:
'we expect that 17-33% of the fossil fuel carbon will still reside in the atmosphere 1 kyr from now, decreasing to 10-15% at 10 kyr, and 7% at 100 kyr. The mean lifetime of fossil fuel CO2 is about 30-35 kyr.., A better approximation of the lifetime of fossil fuel CO2 for public discussion might be ''300 years, plus 25% that lasts forever.'''
References: J. Hansen et al. 2007: Dangerous human-made interference with climate. www.atmos-chem-phys.net/7/2287/2007/ Atmos. Chem. Phys., 7, 2287-2312, 2007; and Archer, D. (2005), Fate of fossil fuel CO2 in geologic time, J. Geophys. Res., 110, C09S05, doi:10.1029/2004JC002625.
Christopher, Walton, UK
Here is a little science lesson: CO2 has a life span of 6 to 8 years and the amount of CO2 in the atmosphere that is man-made (so to speak) is somewhere around the 0.004% mark. Global temperature changes drive atmospheric CO2 levels, atmospheric CO2 levels do not drive global temperature changes - global temperature is driven primarily by the Sun and then by the Ocean (Pacific Decadal Oscillation). The Green Hysteria machine never ceases to amuse me.
Si Robertson, London UK
Oxford University's record on reducing its emissions over last 10 years was disgracefully worse than George Bush's. The writer is right of course to highlight the urgent necessity of not exceeding the carrying capacity of the planet for human-caused CO2 emissions. However, I would disagree with his 2C target, as do most of the developing nations. This would result in appalling biodiversity losses across the planet. We need to get back to 350 ppm. His understanding of how political processes work also needs expanding.
Writing a letter is not going to do it. You need millions of people actually already reducing their carbon footprints so governments can have the courage to take action also.
Donnachadh McCarthy, Peckham
Global Warming is a fact. It has happened in the past and it will happen in the future, as will Ice ages. As for greenhouse Gas, imagine millions of years before we were here. On a twelve hour click face we arrived at 4 minutes to 12, the moon was much closer,so the tides were much greater. The Earth was less dense so there was much less Gravity. This enabled vegetation and Animals to grow to much larger proportions than they could achieve today. Imagine the amount of gas emitted by the Millions of these huge beasts, along with the huge amounts of Volcanic activity produced by a very unstable much thinner crusted Earth. Also consider the effect of the much more active Sun, with its ability to change poles from a Positive to a Negative charge. Perhaps even to the extent of flipping earth upon it's Axix to put the Magnetic Poles where the Equator was. An immediate Ice age. The Electrical energy of the Sun along with the Angle of declination of the Earth will change the Weather patterns of the Earth, remember back in the classroom when the Teacher would rub an Ebonite rod with a Silk cloth too create static electricity, to make water running from the Tap bend toward it.
We are barely worthy of mention in the greater scheme of things, and like the Dinosaurs will most likely be eliminated regardless of what we do. C. Hooper
Colin Hooper, Brisbane, Queensland, Australia.
co2 is not a pollutant and is an extremely small player as a greenhous gas. co2 makes up 0.0386% of the atmosphere and man contributes only 3% of that. climate change is driven by the sun, not co2. has anyone noticed that global temperatures have dropped lately? it's because the sun has gone into a solar minimum which has been predicted to last 20 to thirty years. not one climate model predicted any drop in temperature yet it has happened. clearly some other mechanism is at work besides co2 concentrations.
bill, steamboat springs, co, usa
I fully expect that there will be no discussion at all about deforestation. The destruction of the rainforests releases more carbon dioxide into the atmosphere than all forms of fossil-fuelled transport across the entire globe. But will anything be done about it at the summit?
Just as eco protesters get their priorities wrong by vandalising the few coal-fired power stations we have in this country, so too will the summit delegates get their priorities wrong by interminable waffle about carbon taxes.
Actually CO2 doesn't stay in the atmosphere indefinitely, but only about 7 years, according to the latest research.
And the average increase of 1.6% per year in CO2 emissions hasn't resulted in any increase in world temperatures since 1998. Temperatures have actually fallen in the last three years.
CO2 emissions were increasing dramatically from 1940 - 1972 as well, while world temperatures went through a 30 year period of decreases. There is very little corelation between CO2 changes and temperature changes, other than when temperatures go up, CO2 increases, based on Arctic ice cores going back 700,000 years.
Better keep that coal locked away. People might be fighting to get their hands on it to keep warm in a few years.
Paul Stevens, Hastings, Ontario, Canada
Assuming that one isn't a "skeptic," it doesn't look very good, does it? In the US we've gotten rid of the Bush administration stumbling block, only to find another stumbling block in the form of Republican filibuster threats in the Senate.
Moreover, it appears that in the larger picture, there is simply too much disagreement over who should have to be responsible for what. I don't see good prospects for bridging the gap between developing nations which believe they should get the same free hand that the western world enjoyed in the 19th and 20th centuries, and those now-developed western countries (my own in particular) which believe, eg., that China's total emissions require serious cutbacks regardless of how small they are per-capita.
A global treaty to make serious cutbacks in GHG emissions, starting now, is still the best hypothetical solution, but I'm afraid that in practical terms this approach is just unworkable. The theoretical distant-second of "geoengineering" is, it seems more and more likely, the only practical option available. I suspect that our best bet may be forests of "artificial trees" to capture pollution from the air; as insane as this may sound when we have perfectly good rainforests that need saving, the rich world is much more likely to spend its money on machines which it can design and build at home, and precisely meter.
Matthew Kuhns, Lakewood, Ohio, USA
Lord Dudley put Newcommen's first atmospheric 'fire engine' to work pumping his colliery in 1712; so I'm puzzled as to kicking off the calculations from 1750 ? That trillionth tonne may have already gone up the spout . . .But yes; at some point; we have to stop. Not only carbon emissions, but everything else too. Will the science museum host the "trillionth ton of fish landed", or the trillionth square metre of land concreted over; or the trillionth tonne of biodiversity pushed to extinction? Is some bright spark out there planning for the "trillionth person on the planet?" - to which most "sane rational people" would say; "but a trillion people wouldn't physically fit !?"
So how come these same "sane rational people" miss all the other looming indicators and that 6 billion people here now do not fit. We passed the real "tipping point" at . . what; 2 billion people, 3 billion people ? - somewhere around there, and that was back in the 1970's. No, I'm afraid the "they shall not pass" point was passed way back 30 years ago.
The trouble is; the people who will do something about it, and stop breeding, will be the "nice, quiet, wouldn't say boo to a goose" people . . . The "out for whatever they can get" people; will say "great, more for me . . ." and carry on business as usual; so they are the ones that are going to "fry and die !"- which all kinda works out with the gorgeous irony it deserves !
Well, winter's here; I bet somebody nicks a few bags of that coal before the end of the week.
Steven Walker, Penzance
Science is taking a huge risk at becoming discredited with its CO2 theory. This theory has a 90% confidence rate. But what about the 10%? How is the current profile going to be viewed in 10 years time after further global cooling, in spite of higher CO2 concentrations, with the link to climate and solar activity established? This could turn humans to even more reckless treatment of the planet in future.
Iwan Jones, Horsham
The article is a bit misleading. While emissions have gone up atmospheric increases would be what mattered. The actual atmospheric increases are below the IPCC's projections so we would still only see about a 2C total anomaly even with business as usual. In fact, given the rate of output v/s the change in atmospheric levels of CO2 it may not even be possible to much more than double CO2 concentrations if we burned every last bit of coal known to exist.
Far more important than CO2 is the absurd notion that the energy, economic and industrial systems can somehow be manipulated to produce the results (and secondary results) many suggest. Pretty much every nation that has ever tried anything similar has been held back technologically, economically and socially (health and human rights) and usually been forced to embrace a free(er) market once again.
The newer types of nuclear plants are the best bet if you want to build power infrastructure NOW. There is enough uranium and thorium fuel to provide 120-250 years at the USA's per capita power usage (40kw/hr per day) for a population of 8 billion people! Long before this runs out we will have viable fusion and/or solar to take its place.
Solar-thermal is great but everyone needs to give up their all-or-nothing, anti-carbon attitude and add oil/gas burners that will allow the plants to operate at night and cloudy days...turning it into a base-load plant producing MOST of its power from solar. Since it provides base-load power this type of plant would actually INCREASE the grid's ability to tolerate other, more unstable renewables.
Solar photovoltaic is not yet ready and should never, I repeat NEVER be used as a significant source of grid-connected power at this time. Their manufacture is expensive, produces toxic waste and the expensive panels are prime targets for theft. In its concentrated form (strips of photovoltaic cells in front of parabolic mirrors) it is a bit more viable, but being DC it loses a significant portion of its energy in conversion to grid-compatible DC. Also unlike solar-thermal you cannot simply add a boiler/burner to convert it into a base-load plant. You would essentially need to have an entirely independent power plant for that, which is wasteful and expensive.
Wind...more resource intensive than you think (200 tons of steel, 1000 cubic meters of concrete per 4mw turbine) and you need about 3-5 times nameplate capacity to semi-reliably produce the nameplate capacity. The conditions within a wind farm provide intolerable living conditions for humans and it would take an array half the size of the UK to reliably produce the UK's power demands.
As I mentioned with solar-thermal, if the green groups would stop proposing unimaginably stupid and ineffective energy policies then they would get some of the progress they want and everyone would be happy to do it. Any viable solution that we are capable of undertaking today would necessarily require nuclear for base load, fossil fuels for backup or some of both.
Lloyd Burt, Charlotte, North Carolina, USA
I think those politicians might actually agree on a climate deal. However, it is unrealistic to think that they will agree on all the specifics. They will have a basic plan but most likely continue negotiations on the details into mid/late 2010.
James Hwang, Irvine, US
This is the biggest hoax since Bernie Madoff.
First, the most plentiful green house gas by far is water vapor! Second, where are all the vineyards that were so common in England 1000 years ago? Third, why don't we just disallow volcanic eruptions, that spew more carbon than man has since the beginning of time.
Yes, from the same genius' that brought you Y2K, 'Global Warming'. Except the nasty, real, scientific data confirms that we are now entering a global cooling period. As a matter of fact weather models agree that this winter will see temperatures much below normal in most of Europe with many records broken.
AND as a last parting shot, is the U.N. pressure of two years ago on leading climatologists to endose the stance that increased levels of carbon would cause such a massive increase in hurricanes that the southern coast of the U.S. would be a wasteland. There were no takers, as science did not agree with with such a ridiculous theory. This year to date, there have been no hurricanes in the Gulf of Mexico and hurricane season is almost over.
Tony C, Calgary
Well done Myles. We know both the approaches 'to act immediately' and 'to keep patience'. When somebody submerges in river, people do not see how he reached inside the river or they do not waste time in less important things, their first reaction is to jump and save that person in proper way. On the contrary, when we interact with a nice and honest youth, frustrated with some problem and behaving in angry and violent way, we need appropriate skill and patience to handle him. We require 'infinite patience' to handle some critical situations.
But, when I look at the current trends we are aggressive on most of the places, where we require 'patience' or 'infinite patience' and places where we need to 'act immediately' we are silent with 'infinite patience'. Look at the 'compounding effect' of the existing trends. At one hand population is growing at tremendous pace and on the other hand the natural reserves are rapidly declining. Non judicious life styles are expanding with rapid pace. The definition of 'minimum requirement' has been changed. We can see both 'actual and virtual carbon dioxide, methane and nitrous oxide' in most of our things like electricity, concrete, milk, meat, vegetables and crops grown with fertilizers, transported items, fossil fuel based vehicles etc. We are running on the road where at one point of time, we would face utter crisis of food, water, air etc. with too many people.
Initially things would be difficult. Restricting population, changing life style, changing aggressive existing patterns of the economy would require lot of effort, dedication, skill and planning. Very soon things would become smooth when people would realize that 'the problems of transitions' are less difficult than 'the problems of the existing patterns'.
We do not have to blame anybody. It is the 'ingredients of the system' that needs to be changed. The representatives of the nations are part of the existing system. They represent the country. 'Collective attitude' always dominates the 'personal attitude'. If somebody rebels in the existing system possibility is that he may be thrown out. This is the peculiar nature of the problem. Therefore, need is to design a new system in such a way that it does not come in direct conflict with the existing pattern. Control on population through financial incentives, legislations and other mild means should be the first step in this direction. More we surrender under the existing pattern, more we make our task difficult in the near future. We must design suitable 'small interventions' in the existing pattern so that in the long run we would be able to get 'U turn' in relatively smooth way. The 'great transition' as suggested by Andrew Simms in the previous article must be consisting of many 'small interventions'.
Sanjay Singh Thakur, Indore,India
Ya, I agree with him or her. Though it is not mandatory for them they have a great influence to change the amount of carbon emision and the world should not wait for the leaders, the people should be aware of thier envirnment. I really expect a great solution on the environmental problems atleast to contribut on helping the developing countries to subsidise on changing thier people's awarness to the environmental chalenges. May be the trilions of carbon could burn if the world did not act on it. at last we should fight environmental problems only by teaching people and gowing experts on the field environments.
yukuno yohannes ghebremedhin, Asmara, Eritrea
The Copenhagen Climate Summit will bring together concerned business leaders and governments from around the world to help kick-start the low-carbon revolution. Copenhagen can actually deliver a significant result for the benefit of future generations. It could create millions of new green jobs, unleash huge investments in new, low-carbon markets, and thereby spur economic growth. There will be the strong focus on energy saving and a secure energy supply. To minimize the global warming they must preserve trillionth tonne instead of release until 2050.
Engineer Md Abdus Salam, Kushtia Zilla Parishad, Bangladesh.
Does anybody want to join me in a cunning and devious plan to steal the trillionth tonne? If they can't burn it then at least we will be able to stop global heating at 2 degrees! If only I had known, I would have stolen the 500 millionth tonne and stopped them burning that! I bet that tonne wasn't guarded so well!
Simon Mallett, Maidstone, Kent
History will show that the science of Anthropogenic Global Warming is based on Green hysteria and not actual scientific Facts. Computer predictions have absolutely no record of showing trends that match records from all parts of the planet. The idea that 350 ppm CO2 levels are the only way of avoiding a catastrophe is to ignore actual historical data. The psuedo scientific politically steered Carbon Footprint/Offset/Trading scam is just that, a scam with no proof of its veracity. Vast sums of money are being squandered to produce electrical power by any means other than the cheapest. The need for the latest Nuclear Power designs [as usual, no CO2!] and newer coal fired systems [clean coal is a myth at present] will be needed when the various alternative sources of power, wind/solar etc fail to provide anything more than a token and a very expensive token at that, of the needs of a badly power managed country - the UK. BTW Ozone layer was not saved by banning CFCs. The Ozone layer never had a hole and the present alternative to CFCs is proving to be a beg mistake! Yet another example of Green hysteria blinding the true facts. Myles Allen is reading the wrong books/papers.
Brian Johnson, Farnham Surrey UK
The only agreement that's likely to result from the Copenhagen meeting is an increase in the use of carbon trading, including its application to households and individuals. In other words, nothing is going to be done about the continued rise in emissions.
The trillionth tonne will surely be burnt; if we don't burn it another nation will be happy to buy it from us and burn it for their own use. Oil and Coal are incredibly versatile and energy-dense and while the world's energy requirements continue to rise, which they will, so too will the production of these fuels.
The problem with CCS. Carbon Capture sounds like the solution to all of our problems, necessitating that a value be placed on carbon stored in geological formations through either a carbon tax or a carbon trading scheme. Estimates of the UK's 'viable capacity' (as reported by the BGS) are in the region of 1.2 Gt of carbon in the best sites (i.e. depleted oil and gas fields). The CO2 stored will, for reasons of project economics and the opportunity of recovering a precious and versatile resource, be used in conjunction with EHR (Enhanced Hydrocarbon Recovery). The oil recovered is estimated to be approx. 2 billion barrels of oil - when one considers that North Sea Oil is primarily light and sweet, its fainal use will most likely involve its combustion releasing CO2 to the atmosphere not amenable to capture.
A back of the envelope calculation which did not include energy used in refining showed that there would be little (if any) net-saving of carbon dioxide released into the atmosphere.
It seems to be that any value given to stored carbon simply makes the deal of recovery of difficult-to-get hydrocarbons a little sweeter. It is not surprising that there such an urgency to get the ball rolling on carbon-taxing since from 2010 the oil wells in the north sea will begin to be plugged and to have infrastructure removed, which could otherwise be adapted to CO2-EOR.
Also, is there sound science to suggest that removing a very small amount of CO2 from the atmosphere (while overall world emissions continue to grow) will produce a result that is predictable or even measurable against the background of natural climate variability (little talked about by the IPCC)? I think not.
Besides, if we make drastic carbon cuts and observe surface temperature levelling off we will pat ourselves on the back. If, however, temperatures continue to rise, despite drastic action, we will say that we acted too late!
Being uncertain of the benefits of decarbonisation, are there things we could spend the money on that would have a lot of benefit now (both by improving quality of life and increasing the likelihood of successful adaptation to whatever climate change takes place)? Surely so. (And here I refer you to work done by the Copenhagen Concensus)
C J Brent, Southampton