Low-carbon growth: the only sustainable way to overcome world poverty


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The two great challenges of the 21st century are the battle against poverty and the management of climate change.  On both we must act strongly now and expect to continue that action over the coming decades.  Our response to climate change and poverty reduction will define our generation.  If we fail on either one of them, we will fail on the other. The current crisis in the financial markets and the economic downturn is new and immediate, although some years in the making. All three challenges require urgent and decisive action, and all three can be overcome together through determined and concerted efforts across the world. But whilst recognising that we must respond, and respond strongly, to all three challenges, we should also recognise the opportunities: a well-constructed response to one can provide great direct advantages and opportunities for the other.

Some may argue that the global financial crisis and economic downturn means that we should delay our efforts to tackle poverty and climate change. But delaying on poverty would condemn millions of people to many more years of hardship. And delaying on climate change would mean the stock of GHGs in the atmosphere grows, making the task of dealing with the problem more costly and difficult in the future. We cannot afford to delay. We can and must face up to all three challenges together.

So what do we need to do to combat the threat of climate change whilst boosting efforts to reduce poverty and tackling the global economic downturn?

We know what actions we need to take to cut emissions. They fall broadly into three categories: energy efficiency, low-carbon technologies, and a halt to deforestation. We also know what policies are necessary to drive these actions: tax, carbon trading and regulation; increased technology support; and measures that halt deforestation.

The G8 nations at recent summits have endorsed the goal of reducing global emissions by at least 50% by 2050 (which should be relative to 1990). Such cuts are broadly in line with a path could hold greenhouse gas levels below 500ppm CO2e and then start to reduce them. This could reduce the probability of a 5ºC increase in global temperature from around 50% to 3% or less. The target 50% reduction means halving global emissions from 40 Gt CO2ea year to 20, or little more than 2 t per capita with around 9 billion people in 2050; it also means little scope for deviation of actual emissions from the mean for any major country, developed or developing (note that similar per capita actual emissions does not mean similar per capita quotas).

Developing countries should ultimately want to go low-carbon.  Not only is it the future, but it brings huge benefits beyond climate change. Renewable energy sources can free countries from a dependence on imported fossil fuels.  Cleaner transport and cooling mean less pollution and better health.  Halting deforestation protects water supplies, controls flooding and provides bio-diversity.  The transition to a low-carbon future can bring major economic gains which appear soon.  Energy efficiency can help boost incomes. Low-carbon technologies can open up new sources of growth and jobs.  They can help even the poorest countries leap-frog old approaches – they can avoid some of the cost of large grids in the way cell phones helped cut the need for telephone wires.  And smarter grids can both enhance energy efficiency and enable new technologies whilst cutting transmission costs.  New sources of low-carbon energy – hydro, solar – could help create a comparative advantage for some of the poorest countries.

But the fact remains that no matter how successful we are with mitigation, we are now committed over the next few decades to some degree of climate change due to the levels of GHGs already in the atmosphere and those which will be emitted in the coming years. That means all countries will have to adapt. The challenge is particularly urgent for developing countries as they are earliest and hardest hit. Adaptation is essentially development in a more hostile climate. It is disruptive, and practically and conceptually confusing, to attempt a rigid and comprehensive separation of elements of investments in physical or human capital which are marked for ‘development’ or ‘adaptation’.

Many of the poorest people in the world will be the most exposed and vulnerable to the impacts of climate change that will occur over the next few decades. These are also the people who are least able to afford the costs of adaptation, and who have contributed much less than those in the rich world to the current levels of GHGs in the atmosphere. There is a fundamental inequity here and a strong imperative for the rich countries to provide more funds to developing countries, in addition to current development commitments, to fund the extra costs created by climate change. This is in the rich countries’ direct interest as well: as Archbishop Desmond Tutu argued ‘the problems of the poor will arrive at the doorstep of the wealthy, as the climate crisis gives way to despair, anger and collective security threats.'

Adaptation will increase the burden on developing governments and compensatory funding for this must be additional to current commitments on ODA. As we look forward to the challenges the developing world faces beyond 2015, and we must soon be examining and formulating the successors to the MDGs beyond 2015, I think that our targets for support from the public budgets of rich countries are likely to be closer to 1.0% of GDP than 0.7% for the coming 2 decades.

Since adaptation is basically development in a hostile climate, there is no sense in separating out funds and thereby distorting our efforts.  Some aspects of the ways in which the funds should be allocated will differ from our usual methods for development assistance, for example, where ‘compensation’ for direct climate effects such as rising sea levels are involved, but even this does not imply that we need new institutions to manage them.  One option would be a window alongside IDA. The same would apply for mitigation funding. With the private flows that could come with them and the growth and poverty reduction they could help foster, I think that these flows would constitute very wise investments for the world as a whole as well as being our duty as citizens of the world.

I have focused so far on the two big global challenges of this century. Let me now say something about the current financial and economic crisis; it is the most serious such crisis for 80 years. This crisis is having a deeply damaging effect on the developing world. We should learn two lessons from what has happened. First, the longer risks are ignored and allowed to grow, the bigger the consequences when the crash occurs – and we have seen this unfolding in the financial sector now. We know the scale of risk on the climate change front is altogether of a different and greater magnitude, and so will be the consequences of mismanaging or ignoring it.

Second, the financial and economic crisis brings the critical opportunity to find a driver of long-term sustainable economic growth to lead us out of this crisis: we do not want again to sow the seeds of the next bubble as we emerge from the crash of the last.  The globally declared US$2 trillion global fiscal stimulus for 2009/10, if implemented with a long-term vision, offers the chance to invest in new technologies and investments for low-carbon growth.  This could enable us to grow out of this recession in a way that both reduces the risks for our planet and sparks off a wave of new technologies which will create 2 or 3 decades of strong growth and a more secure, cleaner and more attractive economy for all of us.

We can and must, now and simultaneously, handle the short-term crisis, foster sound development and economic growth in the medium term, and protect the planet from devastating climate change in the long term.  To try to set the three tasks against each other as a three-horse race is as confused analytically as it is dangerous economically and environmentally. In particular, the developed world must demonstrate for all, especially the developing world, that low-carbon growth is not only possible, but that it can be a productive, efficient and attractive route to overcome world poverty. It is indeed the only sustainable route.


Nicholas Stern

IG Patel Professor of Economics and Government and Chair of the Grantham Research Institute on Climate and the Enviroment, LSE

Gerard Pereira
April 01, 2009

It gave me great pleasure to read your article recognizing that climate change and poverty reduction are interrelated. Your response to these two great challenges of the 21st century is in keeping with everything I have proposed for the revitalization of Haiti (the poorest country of the Americas). Indeed, in the website of my corporation (http://www.energinat.com), I contend that sustainable clean energy is the key to reducing and even ending poverty in Haiti and that the salvation of this country will come from harnessing the temperature difference in the tropical ocean (which the world's largest collector of solar energy) for the generation of clean power and large quantities of pure potable water using the the Ocean Thermal Energy Conversion (OTEC) technology. Thus, the sun and the tropical sea constitute a heritage for Haiti's future. Echoing Thomas Edison's words in 1931, "I'd put my money on the sun and solar energy. What a source of power! I hope we don't have to wait 'til oil and coal run out before we tackle that".
Your blog is greatly appreciated.

kibinkiri Eric
April 01, 2009

The fight against climate change cannot be complete without reducing poverty. In my country, there is a significant relationship between poverty, climate change and other global issues like HIV/AIDS. These problems are caused by man due to ignorance, greed, power and corruption. It is very futile to tackle one without looking at the others. The poverty level in my country is too high especially in the rural areas. People are only struggling to find what they can eat in order to live. Women spend long hours on their farms but reap very little at the end of the day. Most people are now running to towns and cities in order to improve their living conditions. However, the situation in towns is still not favourable as the rich gets richer everyday while the poor gets poorer on a daily basis. In schools, programs are poorly conceived without considering the issue of sustainability. There is much talk than action.Schools keep on sending out thousands and thousands of students every year without nothing to do. This has led to an alarming rate of unemployment in the country. Also, in the face of these global crisis, my family associations and so called NGOs are cropping up on a daily basis pretending to be fighting against these issues. For example malaria alone has caused many people to become very rich. However it continues to be the number one killer in Africa. Now is the right time for such groups to become more focus and work for the common good and not for their puckets. Programs should be reviewed to incorporate aspects of sustainability. There should be a link between what is being taught in schools and what is happening in the environment. Ministries should get involved and monitor the activities of these institutions to make sure that students are not stranded on the streets after completing their studies. Alternative solutions and strategies should be offered to the poor to improve their lives. All these issues affects people in the same way and should be tackled from the same angle. Base on this argument i will confidently conclude that low carbon growth is not the only sustainable way to tackle world poverty. Eventhough climate change caused by increasing CO2 in the atmosphere poses serious threats to mankind, solutions to it and world poverty most be looked from different perspectives.To convince people fight an issue like climate change, you must first of all satisfy their basic needs. People sometimes have no choice than to get involved in unhealthy practices which consequently destroy the environment and affects their lives adversely in future.
Thanks very much for your blog
Tel:+237 77 79 03 82

March 30, 2009

For several years now I have been campaigning in Kenya to get an alternative fuel to wood charcoal. Every organization that I have approached thinks we have a "good" idea but no one wants to help us build a factory that will make green charcoal out of agri-waste. This process has been operational in Senegal for over a year now and it is both saving the forests and alleviating poverty. Another factory is being set up in Mali as we speak and both China and the Philippines have expressed interest in this process. It qualifies for carbon credits. Please do you have any suggestions for me? Thank you.

Robert Vincin
March 30, 2009

Unfortunately we have the wrong folk attending Major Environmental decision making assemblies. The prime issues at present is save the Banks. The only assets on the Planet are Water Atmosphere Soil Vegetation WASV all else commodities including printing press and all else commodities.
I am Guest Foreign Expert in PRC together we are planting out 200million hectares of C4 UNFCCC article 3.3-3.4 vegetation sequestering 25b tonne CO2. The point is the 300yrs of global CO2e build-up toxic water soil deserts loss of the precious BEES and like need action now, as we have 4 years to perfect replicating nature. Desk jockeys are never at poverty's face never see a lake filled with sand or algae or a child die wanting a glass of potable water or a flame to cook the world supplied rice wheat.
The solution for the US lead financial crash is, do a Roosevelt, and rebuild today the infrastructure assets, replicate NATURE, but do in according to the well thought out UN - FCCC rules. The developed world cast aspersions upon PRC but she has here hand up recognizing problem cause effect and implementing a we-solution.
Einstein no BEES no food no Man. Rebuild your infrastructure quit throwing stones you live in a glass transparent house. Follow Natures and Gods' master plan 2million US folk will start tomorrow all it need is a Global leader today. You can do it by 2012 and take your place back at the table tomorrow Robert Vincin Beijing in a we program

architesh panda
June 10, 2009

it is very interesting to read the views u have expressed here. It is exactly the same what i heard in your public lecture given in Bangalore, India. There i pointed out one query that how to integrate both poverty reduction efforts and climate change mitigation. U have argued in favour of a low carbon path for developing countries. I would like to point out that developing countries need growth to eradicate poverty, and growth itself means some level of GHGs emissions in production consumption and international trade. Low carbon path certainly is the only way to do it. But transiting to a low carbon path will take time due to the past investments developing countries have already made in carbon intensive development path. Giving thrust to mitigation means lowering suddenly the growth rate of the economies which will inturn effect poverty reduction efforts. At the same time they are most vulnerable to the impacts of climate change and adaptation to climate change is the priority now. I doubt how far developing countries can go with the rapid reduction of GHGs in the face of pressures of adaptation to climate change.
Thank you very much for ur ideas.

June 25, 2009

In regard to the animal world, there are entire branches of the animal kingdom, such as reptiles and insects that thrive with higher temperatures. The fossil record shows the existence of large tropical reptiles that required temperatures in excess of 5 degrees cent. more than todays levels. Tropical forests are robust and adaptable systems over a quite wide range of mean planetary temperatures. It is believed that dinosaurs lived with atmospheric C02 concentrations of 1000 per million (i.e. more than double todays level of 380ppm.) The ecological systems of the planet are thus highly adaptive and there is no optimum temperature for the planet. Some habitats will thrive whilst others will suffer as a result of temperature change. It is simply not a scientifically meaningful question to ask if temperature increase is good for the planet.
Aside from factors such as human destruction of forest habitats, temperature increase per se has a number of generally beneficial effects on plant life. Higher temperature causes increased evaporation and rainfall, which is beneficial for plants. Temperature increase also raises the tree line. In the equatorial zones, such as the Bolivian Andes and the Himalayas, the tree line is almost 5000 m, whereas in northern Scandinavia it is 1000 m. approx.(See http://en.wikipedia.org/wiki/Treeline)
Thus temperature increase enlarges the envelope in which plant life is viable. Incidentally, CO2 in small quantities is beneficial for plants and enhances plant growth. It is a sort of air borne fertiliser or plant food. It is also possible that temperature increase would enhance agricultural productivity on certain upland habitats. These are the main ecological advantages of planetary temperature increase.
The climatic effects of temperature increase can be summarised as a series of shifts in the main climatic zones. Globally there are a number of distinct climatic zones. These are attractively illustrated at http://en.wikipedia.org/wiki/File:MeanMonthlyP.gif This interactive map shows the seasonal oscillation of weather around the equatorial zone. The highest levels of heat and rainfall are concentrated in the tropical/equatorial zones. The map shows the effect of planetary rotation on habitats, due to the Coriolis effect. Tropical/monsoon rain patterns lie on a sort of S.W. to N.E. axis as does the band of desert areas running from the south western Sahara to the Gobi deserts.
In terms of a schematic summary the other main zones or global habitats are: desert, polar/tundra, savannah/Mediterranean and temperate/agricultural.
Temperature increase is liable to have the following broad consequences on these habitats:
Tropical/equatorial zone: intensification
Savannah: diminution
Desert: intensification.
Temperate/agricultural: intensification.
Polar/tundra: diminution.

[The current debate relates to mean temperature and does not necessarily imply a change in maximum and minimum temperatures (e.g. lowest polar and highest desert temperatures).]

In human terms it is notable that there will be large agricultural gains in areas such as Russia, Canada and Scandinavia. Climatic conditions in the United Kingdom are benign across the entire range of temperatures currently under political consideration. Intensification of desert areas is a process that has been going on since the end of the Ice Age. It is very notable in western China and the Gobi desert. In fact, trade routes over the Silk Road were known to have shifted northward before the time of Marco Polo as a result of desertification. Global temperatures have been increasing since the end of the Ice Ages. In general terms an Ice Age will have a dry climate with low sea levels because most of the planets fresh water is frozen in ice sheets. Strictly speaking the increase in sea levels since the Ice Age is a non-climatic phenomenon. Sea level increase is the only possible danger facing the U.K. There is no significant sign of it at present.
By contrast, a warm period is associated with rainfall, evaporation, higher cloud levels and higher sea levels. Thus there is a correlation between moisture and warmth that is particularly strong in the equatorial regions. Moderate global warming , in aggregate, is therefore likely to be beneficial for life forms, in particular plant life.

July 05, 2009

The UK government has a policy of switching to a low carbon economy.

1.The direct effect of burning fossil fuel on atmospheric CO2 is quite small, about 25%-35%.
2.There are many causes of increased atmospheric CO2 that have nothing to do with burning fossil fuel. An increase in solar activity or cutting down a large amount of rain forest could cause increase atmospheric CO2. The science is highly uncertain.
3. There are also causes of temperature increase, other than atmospheric CO2, such as methane, water vapour etc. The science is highly uncertain.
4. Increasing quantities of atmospheric CO2 have a diminishing temperature/greenhouse effect. Therefore, future economic growth is less polluting than past economic growth. So one can establish the saturation level of atmospheric CO2 p.p.m. at which carbon use is pollution-free.

The government is in a position to question its own policy, if it chooses to do so.

Hadley predictions: CO2 parts per million.
The UK government (Hadley Centre) has announced temperature predictions for 2010-2060 based on 12 different climate models. They state that their central estimate for temperature increase over 50 years (2010-2060) is 2 deg.cent. The figure applies to the entire UK area and is essentially a global estimate or at least a northern hemisphere effect. The Hadley centre states that the land carbon cycle is expected to become less efficient at absorbing CO2 as the climate warms and that this area of science has substantial uncertainty. Here is an e-mail from the centre in which they accept that it is not so much increasing industrial emissions of CO2 but the ability of the biosphere to absorb CO2 that will account for increased C02 ppm in future:
"The rate of growth in atmospheric CO2 concentration depends on future fossil fuel usage, and on the ability of the biosphere to absorb CO2. The IPCC SRES scenarios used for UKCP09 all predict emissions of CO2 to increase during the first half of the 21st century, while the land carbon cycle is expected to become less efficient at absorbing CO2 as the climate warms. Consequently, the rate of CO2 build up in the atmosphere over the next 50 years is projected to be higher than in the recent past. There is still substantial uncertainty in the strength of feedbacks between climate and the carbon cycle that determine CO2 uptake, so the UKCP09 projections sample a range of land carbon cycles consistent with current understanding. For the SRES A1B scenario the projected median value for mean atmospheric CO2 concentration for the period 2050-2070 is 600 ppmV. The projected 10-90% range for this period is 520-650 ppmV with A1B forcing. More detailed analysis will be presented in future publications from the Met Office Hadley Centre."

Enquiries Officer
UK Climate Impacts Programme
School of Geography and Environment.

When one takes a closer look at the predictions, one sees that it is difficult to account for an increase of this magnitude in terms of CO2 emissions alone. The Hadley estimates for 2010-2060 appear to be based on uncertain theoretical models and computer predictions about secondary greenhouse effects other than CO2 such as methane, aerosol pollutants and water vapour etc. Society is being asked to make reductions in carbon usage, even though fossil fuel itself is not necessarily the actual culprit. It is important to keep the public well informed about all the alleged causes of global warming.
The following graphic http://www.ipcc.ch/graphics/graphics/syr/fig2-3.jpg shows an increase in atmospheric CO2 parts per million for 1960-2000 of 50. It is a simple linear function and one can therefore use simple extrapolation to estimate a figure for the increase in atmospheric CO2 parts per million of 125 per 100 years. Taking a current value of 390 CO2 ppm for 2010 and taking 1760 as the base year for the pre-industrial initial state of CO2 ppm =280, one might thus estimate cumulative atmospheric CO2 as follows:

1760 280 ppm approx.
1960 340 ppm approx.
2010 390 ppm approx.
2060 450 ppm approx.
2110 515 ppm approx.
2145 560 ppm approx.

(These atmospheric CO2 figures will be used later to estimate temperature increases. See below. N.B. There is not complete consistency in these numbers due to different estimating rules).

These estimates of future cumulative CO2 emissions for the period 2010-2145 are essentially calculations about the path of future economic growth, particularly in China and India, that would have been provided to the Hadley Centre (Met.Office) by an outside source.
By contrast, the Hadley centre predicts that CO2 ppm increase for 2010- 2060 will be up from the current level of 390 ppm to 600 CO2 ppm in 2060, far more than suggested above. Can CO2 ppm really grow more than 210 in 50 years? This is only possible if non-fossil fuel feedbacks, such as methane and falls in aerosol pollution, deforestation etc. account for 2/3 of the increase in CO2 ppm. According to the centre most of the increase in CO2 ppm is thus due to changes in the ability of the biosphere to absorb CO2 as the climate warms (i.e. feedbacks).
Although the Hadley Centre claims that future CO2 ppm increase is not simply linear, reality shows that carbon intensivity per unit of GDP is falling naturally in USA and EU. Russia, an example par excellence of an old smoke-stack economy, is the country with the highest carbon intensivity per unit of GDP in the world.
It is doubly difficult to see how atmospheric CO2 alone could account for a 2c. increase over the next 50 years in view of the following fact:
"...This means that a doubling of CO2 from a different value (say, from the present value or from 560 ppm) gives the same forcing as a doubling from 280 ppm. But the response of the climate system, of course, could differ somewhat for different initial states, which is why doubling from 280 ppm should be included in any exact definition..." Stefan Ramhstorf, member of IPCC.
In other words, the marginal rate of CO2 temperature effect is falling. Increased quantities of CO2 emission have a diminishing greenhouse effect. Therefore, future economic growth is less polluting than past economic growth. Increased levels of atmospheric CO2 will have a very diminished temperature effect beyond 560 p.p.m. So one must establish the saturation level of atmospheric CO2 p.p.m. at which the temperature effect becomes negligible. This is the level at which carbon use is pollution-free. And specifically, in the range where we are today, a doubling of CO2 from the current level of 390 ppm to 780 ppm would have temperature effect of 3c.+/-1.
Hadley predictions: Temperature Increases.
The basic historical model of the CO2 greenhouse effect is that, starting from the initial pre-industrial level of 280 p.p.m. of atmospheric CO2, a doubling from 280 ppm to 560 ppm has a temperature effect of 3c +/- 1. Leaving aside other factors such as the methane effect, aerosols and claims about water vapour and applying this greenhouse effect for CO2 to the above estimates of future levels of atmospheric CO2, one can make the following alternative estimates of future temperature increase, based on CO2 emissions alone:

For: the period 2010-2060 (390 ppm to 450 ppm) = 60 increase in CO2 ppm
At 3c (per doubling of CO2):= 0.64 deg.cent increase.
At 4c (per doubling of CO2):= 0.857 deg.cent increase.

These values are below the range of the Hadley estimates. If CO2 were the major cause of global warming, the 2c temperature increase that is proposed by the Hadley Centre would require a CO2 ppm increase in the order of 140 ppm over 50 years. This is scarcely a probable estimate on the basis of likely future economic development.


from 2010 to 2145 (390 ppm to 560 ppm) = 170 increase in CO2 ppm.
At 3c (per doubling of CO2):= 1.82 deg.cent increase.
At 4c (per doubling of CO2):= 2.428 deg.cent increase.

For convenience one may use 1760 as a base year for the start of industrial activity and subsequent human influence on the atmosphere. My understanding is that human activity caused 1c. temperature increase over 1760-1960 and a further 0.5c. increase over 1960-2010. The rate of temperature increase in the period 1960-2010 was thus already 2 times greater than the rate for 1760-1960. The Hadley centre now predicts a further 2c. temperature increase making a total increase of 3.5c. for the period 1760-2060. The UK government is suggesting that CO2 ppm increase for 2010- 2060 will be up from the current level of 390 ppm to well in excess of 600 CO2 ppm. Can CO2 ppm really grow more than 210 in 50 years? This is only possible if non-fossil fuel effects and feedbacks account for 2/3 of the increase in CO2 ppm.

Supriya Francis
July 15, 2009

It is a false dilemma to say that we either fight poverty or save our planet. We definitely need to focus our efforts on sustainable development which will not just help fight poverty but also climate change in the long-term. Much has been said and it’s time for some action now. If we don’t do something about this today, we may not be able to ‘afford’ our future anymore.

Thanks for the blog entry!

Dr P K Rao
October 05, 2009

Dear Lord Stern,
Glad you contributed significantly on important aspects. It is high time the rich (memebrs of societies as well as nations) recognize their ecological footprints in their choice consumption and address the global warming as well as related environmental problems sensibly. Cutting down on red meat consumption, for example, stands to contribute toward reduction of a fifth of greenhouse gases almost costlessly. Indidivual and public polcies need to pay much greater attention to consumption-orinted greehouse gas rgimes and their containment with fiscal measures wherver needed.
Thank you very much,
Dr P K Rao, Princeton, USA.

Jeff Glassman
January 10, 2010

Dear Lord Stern,

In the Stern Review, you say with regard to the Hockey Stick controversy,

>>Much discussion has focused on whether the current trend in rising global temperatures is unprecedented or within the range expected from natural variations. … [¶] Climate change arguments do not rest on “proving” that the warming trend is unprecedented over the past Millennium. … However, they [the National Research Council] state that in some regions the warming is unambiguously shown to be unprecedented over the past millennium. Stern Review, Part I, Box 1.1, p. 6.

Ignoring that science is never about "proving" matters anyway, you argue that being unprecedented is not determinative. Good. But then you conclude after some discussion and by (peer-reviewed?) authority that the unprecedented warming is unambiguously true. This argument is inconsistent.

Further, you rely on the present levels of GHGs being unprecedented:

>>Current levels of greenhouse gases are higher now than at any time in at least the past 650,000 years. Fn 5

>>Fn 5: Siegenthaler et al. (2005) using data from ice cores. The same research groups recently presented analyses at the 2006 conference of the European Geosciences Union, which suggest that carbon dioxide levels are unprecedented for 800,000 years. Stern Review, Part I, ¶1.2, p. 2

Assuming your facts were true for the moment, you seem to adopt the argument that because the modern warming and modern CO2 concentrations, in particular, are unprecedented that CO2 is known to be the cause of warming. This is the common error of using correlation in place of modeling cause. In fact before any human influence, the warming dominantly preceded the CO2. Therefore CO2 could not have been the cause, and further the shape of the CO2 increase followed Henry's Law showing that it dominantly came from surface waters. This result validates the model that warming adds CO2 by the mechanism of outgassing, and no reason exists that that process is not on-going in the modern era. Henry's Law demands it be so.

Now to the facts: Your statement cited from ¶1.2 is common in the IPCC and peer reviewed literature, but is false without a major qualification. It would be correct to say,

Current levels of greenhouse gases AVERAGED OVER A FEW MINUTES are higher now than at any time in at least the past 650,000 years AVERAGED OVER MANY DECADES.

Mathematics demands it be so. As you have elsewhere noted, this interval refers to ice core records, and the 650,000 figure comes from the Vostok data set. Ice core analysis releases gas from firn ice, and firn ice requires perhaps as little as 40 years, and more likely 70, to several thousand years to close. This means that the ice core method, actually like all detection and measurement processes, is a low pass filter. All such processes measure the average over the aperture, in both time and space. Ice core data reduction is no exception, and is extraordinarily slow. This applies not only to the greenhouse gases, CO2 in particular, but also to temperature determined from the non-greenhouse gases, deuterium or oxygen isotopes. The gases collected are the total during the time that the aperture is open. When comparing with past methods, modern instruments may be considered instantaneous. Ice core data greatly reduces the true variability by what is known as a variance reduction ratio. They produce extremely long term averages.

Furthermore, Vostok sampling, for example, has an interval of about 1,400 years. If the firn ice closes in 40 years, the probability of including an event like the modern record from Mauna Loa is about 3%. No amount of signal processing can fix this problem. What can be said about the past records of temperature and GHGs is that the answer lies somewhere between (1) a 97% confidence that it would have been missed altogether for short firn closure times, and (2) the magnitude of the ancient gases is reduced to, say, about 3% of the average modern level for long closure times, that is, on the order of a few millennia or less. In summary, the Vostok record would have missed a short event like the MLO 50-year rise in CO2, or the temperature rise since the Little Ice Age, because it skipped the event altogether or because the event was lost in the long time required for the firn to close.

The statements that the modern record is unprecedented for either temperature or CO2 are invalid. The conclusion that CO2 is the cause cannot be validated based on these considerations, and in fact is invalid in a climate model that would include the following effects that IPCC and the peer-reviewed climatologists err to omit: (1) the on-going natural warming processes, (2) the outgassing of GHGs under Henry's Law, (3) the saturation effect of GHG absorption under the Beer-Lambert Law, and (4) the powerful negative cloud albedo feedback that stabilizes Earth's climate in the warm state.

The flat-Earther is myopic -- his horizon is fore-shortened. He doesn't see that the ships in the distance go down by the waterline. We each need to see that the proxie records, whether from tree rings or ice cores, are down by the waterline. Anthropogenic Global Warming is analogous to the flat Earth. It is the flat Earth climate.

July 25, 2013

>>It is a false dilemma to say that we either fight poverty or save our planet.
Totally agree. We must not kill our planet consuming more and more.
Reuse - Reduce - Recycle. There are a lot of ways for responsible development and consuming.

Stella Bennett
April 27, 2015

I believe it unjustifiable to say that we can either save our planet or relieve poverty, two of the major problems facing our world today and jeopardising our future. We definitely need to focus our efforts on sustainable development which will not just help fight poverty but also climate change in the long-term. I believe that senior members of societies and even nations must recognise their ecological footprints in their choice consumption and address the global warming as well as related environmental problems in a sensible way. Cutting down on red meat consumption, for example, it said to contribute toward a reduction of a fifth of greenhouse gases with no large costs involved. Individual and public polices need to pay greater attention to consumption related greenhouse gas regimes and their management with fiscal measures where required - Stella Bennett

John Troy
May 02, 2015

You make a very good point. There are clearly many aims and one doesn't have to ignore one to achieve the other. Indeed, as you suggest, it could well be the case that by education climate change and poverty can be reduced. The difficulty is that as growth takes place, and this tends to be accompanied by education, greenhouse gas emissions tend to increase in the short run.

Thomas Farrell
April 28, 2015

This article, unlike the one written in the FT in the Economists' Manifesto seeks to outline short, medium and long-term solutions. As a geographically based economist, it seems only natural that this would be at the forefront of your thinking because short and long term solutions are fundamental in exploring issues in this field. I like it when you said what will reduce carbon emissions, "energy efficiency, low-carbon technologies, and a halt to deforestation" but also how you go onto outline how this would be achieved, "We also know what policies are necessary to drive these actions: tax, carbon trading and regulation; increased technology support; and measures that halt deforestation."
I agree that the developed countries should help less developed countries in trying to achieve this world where carbon emissions are substantially less and we live in a greener, more prosperous environment. However, from the point of view of the developing countries, Stern seems to get it wrong. You don't fully balance the argument to support the possibility that the developing countries think this is unfair. Developed countries, like the UK, have been guzzling away for centuries achieving massive economic gains but now the developing countries have to pick up the slack from our selfishness? Perhaps I am being harsh but I would have appreciated if you entertained the possibility that the developed countries need to take a more serious look at themselves rather than trying to offset their issues to developing parts of the world.

John Troy
May 02, 2015

I agree that the to achieving fairness is some degree of redistribution of income between countries in order to reduce the danger of climate change. Thomas made a very good and fair point. The point of view of the developing world.