Global Warming – Willis Ceramics

2010 Diary week 48
Climate Change: A strategy for action

Book Review
Below you will find Part 3 of the review of Chapter 10 of Global Warming: The Complete Briefing by John Houghton with the title ‘A Strategy for Action to Slow and Stabilize Climate Change’. These are the conclusions.

Summary of the action required
• Some actions have already been taken which have an effect on global emissions of greenhouse gases, namely: the reduction by some countries of carbon dioxide emissions in the year 2000 to 1990 levels and the provisions of the Montreal Protocol regarding the emissions of CFCs and CFC substitutes.
• Other actions that can be taken at little or no net cost and which are good to do for other reasons are the following:
 A reduction of deforestation,
 A substantial increase in afforestation,
 Some easy-to-do reductions in methane emissions,
 An aggressive increase in energy saving and conservation measures,
 Increased implementation of renewable sources of energy supply.
• The world needs to follow an energy scenario which will lead to the stabilization of carbon dioxide concentration in the atmosphere.
• We have presented arguments suggesting that, at the current state of knowledge, the range 400-500 ppmv in carbon dioxide concentration is where further detailed consideration of costs and impacts should be concentrated.
• An example of an energy scenario which would stabilize carbon dioxide concentrations in this range is the World Energy Council scenario C.
• Its realization will require that means be provided to enable developing countries to apply appropriate and efficient technologies to their industrial development, especially in the energy sector – matters which will be addressed in detail in the next chapter.

GLOBAL WARMING
THE COMPLETE BRIEFING
JOHN HOUGHTON
Co-Chairman of the Scientific Assessment Working Group of the Intergovernmental Panel on Climate Change
CAMBRIDGE UNIVERSITY PRESS REPRINTED 1999
PART III

Chapter 10: A Strategy for Action to Slow and Stabilize Climate Change
Following the awareness of the problems of climate change aroused by the IPCC scientific assessments, the necessity of international action has been recognized. In this chapter I address the forms that action could take.

The Climate Convention
• The United Nations Framework Convention on climate change signed by over 160 countries at the United Nations Conference on Environment and Development held in Rio de Janeiro in June 1992 came into force on 21 March 1994. It has set the agenda for action to slow and stabilize climate change.
• Developed countries should take action to return greenhouse gas emissions, in particular those of carbon dioxide, to their 1990 levels by year the 2000. Concentrations of greenhouse gases in the atmosphere should be stabilized ‘at a level which would prevent dangerous anthropogenic interference with the climate system’, the stabilization to be achieved within a time-frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner.

Forests
• Over the past few centuries many countries, especially those at mid-latitudes, have removed much of their forest cover to make room for agriculture. Many of the largest and most critical remaining forested areas are in the tropics.
• Over the decade of the 1980s the average loss was about 1% per year. Such rates of loss cannot be sustained. Reducing deforestation makes a substantial contribution to slowing the increase of greenhouse gases in the atmosphere, as well as the provision of other benefits such as guarding biodiversity and avoiding soil degradation.
• For every square kilometer, a growing forest fixes between 200 and 500 tonnes of carbon a year. If an area of 100,000 square kilometers, a little more than the area of the island of Ireland, were planted each year for 40 years – starting now (first edition was published in 1994) – by the year 2035, 4 million square kilometers would have been planted, that is roughly half the area of Australia.
• By the time the new forests matured – between 40 and 100 years after planting (the actual period depending on the type of forest) – between about 25 and 50 Gt of carbon from the atmosphere would have been sequestered.
• This accumulation of carbon in the forests is equivalent to between about 5% and 10% of the emissions due to fossil fuel burning in the business-as-usual scenario during the first half of the next century. It would provide a useful contribution to any required reduction in atmospheric carbon dioxide concentrations.
• Is such a tree planting programme feasible and is land on the scale required available? The answer is almost certainly, yes. Recent studies* have identified land which is not presently being used for croplands or settlements, much of which has supported forests in the past, of an area totaling about 3.5 million square kilometers. (* The study is S. Brown et al., ‘Management of forests for mitigation of greenhouse gas emissions’, chapter 24 in Climate Change 1995: Impacts, Adaptations and Mitigation of Climate Change, eds. R. T. Watson, M. C. Zinyowera and R. H. Moss, CUP, 1996.)
• About 2.2 million square kilometers of this total is land which is technically suitable at mid and high latitudes. – all of this is deemed to be available. In tropical regions, of the 22 million square kilometers actually deemed suitable, only 6% or 1.3 million square kilometers is considered actually available because of additional cultural, social and economic constraints.
• These studies have also considered in detail how much carbon could be sequestered between the years 1995 and 2050 by a programme of forestation on this land. It is estimated to be between 50 and 70 Gt of carbon, to which a further 10-20 Gt can be added if the rate of tropical deforestation were to be slowed.
• Estimates of the cost of carrying out the programme have also emerged from the studies; they are considerably lower than those estimated earlier in the 1990s.
• When expressed per tonne of carbon sequestered they typically fall between $US2 and 8 not including land and transaction costs, but also not including the value of local benefits (for instance, watershed protection, maintenance of biodiversity, education, tourism and recreation) which might be derived from the programme and which, in some circumstances, might offset most of the programme’s cost.
• Compare this figure with the estimate given in Chapter 9 of between $US50 and 100 for the cost per tonne of carbon of the likely damage due to global warming.
• The programme appears as a potentially attractive one for alleviating the rate of change of climate due to increasing greenhouse gases in the relatively short term.
• Once the trees are fully grown, the sequestration ceases. Forests may be ‘protection’ forests for the control of erosion or for the maintenance of biodiversity. Or they may be production forests, used for biofuels or for industrial timber.
• If they are used for fuel, they add to the atmospheric carbon dioxide but, unlike fossil fuels, they are a renewable resource. As with the rest of the biosphere where natural recycling takes place on a wide variety of timescales, carbon from wood fuel can be continuously recycled through the biosphere and the atmosphere.
• As we shall see in the next chapter, biomass is seen as an important renewable energy source for the future.

Reduction in the sources of methane
• Methane is a less important greenhouse gas than carbon dioxide, contributing perhaps 15% to the present level of global warming. The stabilization of its atmospheric concentration would contribute a small but significant amount to the overall problem.
• Because of its much shorter lifetime in the atmosphere (about 12 years compared with 100-200 years for carbon dioxide), only a relatively small reduction in the anthropogenic emissions of this gas, about 8%, would be required to stabilize its concentration at the current level.
• There are three sources arising from human activities which could rather easily be reduced at small cost. Firstly, methane emission from biomass would be cut by, say, one third if deforestation were drastically curtailed.
• Secondly, methane production from landfill sites could be cut by at least a third if more waste were recycled or used for energy generation by incineration or if arrangements were made on landfill sites for the collection of methane gas (it could then be used for energy production or if the quantity were insufficient it could be flared, turning the methane into carbon dioxide which molecule for molecule is less effective than methane as a greenhouse gas). Waste management policies in many countries already include encouragement of such measures.
• Thirdly, the leakage from natural gas pipelines from mining and other parts of the petrochemical industry could at little cost (possibly even at a saving in cost) also be reduced by, say, one third.
• An illustration of the scale of the leakage is provided by the suggestion that the closing down of some Siberian pipelines because of the major recession in Russia has been the cause of the fall in the growth of methane concentration in the atmosphere from 1992 to 1993. Improved management of such installations could markedly reduce leakage to the atmosphere, perhaps by as much as one quarter overall.
• Fourthly, with better management, options exist for reducing methane emissions from sources associated with agriculture. (* The study is V. Cole et al., ‘Agricultural options for mitigation of greenhouse gas emissions’, chapter 23 in Climate Change 1995: Impacts, Adaptations and Mitigation of Climate Change, eds. R. T. Watson, M. C. Zinyowera and R. H. Moss, CUP, 1996.)
• Reductions from these four sources could reduce anthropogenic methane emissions by over 40 million tones per annum which would be more than adequate to stabilize the concentration of methane in the atmosphere at about or below the current level.
• Put another way, the reduction in methane emissions from these sources would be equivalent to a reduction in annual carbon dioxide emissions producing about one third of a gigatonne of carbon or a little less than 5% of total greenhouse gas emissions – a useful contribution towards the solution of the global warming problem.

Stabilization of carbon dioxide concentrations
• We now turn to the stabilization of the atmospheric concentration of carbon dioxide, the most important of the greenhouse gases that result from human activities.
• Under a business-as-usual scenario, emissions will continue to increase throughout next century (2100) with no sign of abatement. The concentration of carbon dioxide also rises continuously through that period; it increases to about two and a half times its pre-industrial value by the year 2100.
• Under this scenario of continually increasing emissions no stabilization of carbon dioxide concentration, and hence no stabilization of climate, is in sight.
• Suppose after the year 2000, all countries kept their carbon dioxide emissions constant, would that be enough? Stabilizing concentrations is, however, very different from stabilizing emissions.
• With constant emissions after the year 2000, the concentration in the atmosphere would continue to rise and would approach 500 ppmv by the year 2100.
• After that the carbon cycle models predict that, because of the long time constants involved, the carbon dioxide concentration would still continue to increase although more slowly; there would be no stabilization for at least several hundred years.
• A study published by the IPCC presents many pathways to stabilization. The profiles illustrate that, to a first approximation, the stabilization concentration level depends more on the accumulated amount of carbon emitted up to the time of stabilization than on the exact concentration path followed en route to stabilization.
• This means that the alternative pathways which assume higher emissions in earlier years require steeper reductions in later years.
• If the atmospheric concentration of carbon dioxide is to remain below 500 ppmv, the future global annual emissions averaged over the next century cannot exceed the current level of global annual emissions.
• It is instructive to look at annual emissions of carbon dioxide due to the combustion of fossil fuels expressed per capita. Averaged over the world in 1990 they were about 1.1 tonnes (as carbon) but they varied very much from country to country.
• For developed countries and transitional economy countries in 1990 they averaged 2.8 tonnes (ranging from 1.5 to 5.5 tonnes) while for developing countries they averaged about 0.5 tonnes (ranging from 0.1 to, in some few cases, over 2 tonnes).
• Looking ahead to the year 2100, if the world population rises to 12 billion (the United Nations base case), under the profiles of carbon dioxide emissions leading to stabilization at concentrations of 450 ppmv, 550 ppmv and 650 ppmv respectively the per capita annual emissions averaged over the world would be about 0.25, 0.5 and 0.7 tonnes – all much less than the current value of 1.1 tonnes.

Realizing the Climate Convention objective
• To decide how the appropriate stabilization levels should be chosen as targets for the future we look to the guidance provided by the Climate Convention Objective which states that the levels and timescales for their achievement should be such that dangerous interference with the climate system must be prevented, that ecosystems should be able to adapt naturally, that food production must not be threatened and that economic development can proceed in a sustainable manner.
• We do not yet know enough to pick precisely the levels or the timescales under the criteria the Climate Convention is prescribing, but perhaps already some limits can be set.
• Firstly, considering the most important greenhouse gas, carbon dioxide, its long life in the atmosphere provides severe constraints on the future emissions profiles which lead to stabilization at any level.
• Stabilization below about 400 ppm would require an almost immediate drastic reduction in emissions. Such reduction could only be achieved at a large cost and with some curtailment of energy availability and would almost certainly breach the criterion which requires ‘that economic development can proceed in a sustainable manner.’
• What about the upper end of the choice level? Here we refer to the likely impacts of climate change under a situation in which the atmospheric concentration of carbon dioxide has doubled from its pre-industrial value of 280 ppmv to about 560 ppmv.
• We noted in Chapter 9 that, as far as we are able to estimate at the moment, the costs of the likely damage of the impacts at that level of climate change were larger than the costs of stabilizing carbon dioxide concentration at levels above 400 or 450 ppmv.
• We also noted that, beyond the doubled carbon dioxide situation, the likely damage due to greenhouse gas climate change is likely to rise substantially more rapidly as the amount of carbon dioxide in the atmosphere increases.
• A further factor is the rate of climate change which, with all the profiles except possibly the two lowest, is likely to be such that some important ecosystems may not be able to adapt to it.
• Considering carbon dioxide alone, these considerations suggest that the range between 400 ppmv and 550 ppmv is where further careful consideration of the choice of the target stabilization level should be made.
• Although carbon dioxide is the most important greenhouse gas, other gases also make a contribution to climate change. As we saw in Chapter 3 the combined effect of the increases to 1990 of the gases methane, nitrous oxide and the CFCs is to add a forcing equivalent to that from an additional 45 ppmv or so of carbon dioxide.
• The effect of this would be that the 450 ppmv carbon dioxide level would become just over 500 ppmv and the 550 ppmv level would become about 620 ppmv equivalent of carbon dioxide.
• This means that the stabilization limit for carbon dioxide only is no more than 500 ppmv.
• There are other scientific factors to be included: troposperic ozone; aerosols; different regional climate responses; different timescale responses; the effect of feedbacks; other impacts such as acid rain from aerosols.
• In Chapter 9, weighing the importance of the needs of the present generation against those of future generations – or inter-generational equity – was mentioned as a core component of the concept of sustainable development.
• Also of importance is the balance of equity between the industrial and developed nations and the developing world – we can call it international equity.
• Taking all factors into consideration will involve different kinds of analysis: cost benefit analysis; multicriteria analysis (which takes into account factors that cannot be expressed in monetary terms); and sustainability analysis (which considers avoidance of particular thresholds of stress or of damage).
• Because much uncertainty is associated with many of the factors, the process of choice is bound to be an evolving one subject to review – a process often described as sequential decision making.
• Finally we look at an example of a pathway to the stabilization next century of carbon dioxide concentration of about 450 ppmv – within the range we have mentioned above – as provided by the World Energy Council ecologically driven scenario (Scenario C) described in Chapter 3.
• Under that scenario, global carbon dioxide emissions grow by about 10% by the year 2050; they then fall by a factor of two by the end of the next century.
• Up to the year 2020, emissions from fossil fuels in the developed world are allowed to approximately double, while those from developed countries fall by about 30%.
• In 2020, global emissions from developing countries would be 60% of the total for the world compared with about one third in 1990.
• Reductions in emissions will be required by all nations during the greater part of the next century (2100).
• As the World Energy Council point out in their report, achievement of such a scenario will be far from easy. It requires three essential ingredients.
• The first is an aggressive emphasis on energy saving and conservation. Much here can be achieved at zero net cost or even at a cost saving.
• The second ingredient is an emphasis on the development of appropriate non-fossil fuel energy sources leading to very rapid growth in their implementation.
• The third is the transfer of technologies to developing countries which will enable them to apply the most efficient technologies to their industrial development, especially in the energy sector.

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