(*Warning – long blog ahead) Longer term readers of Troppo Armadillo will know that one of my pet hobbyhorses has been the global warming debate. However, I’ve been a bit remiss of late. Ken Miles (the UnAustralian) has been blogging away for weeks, undertaking an admirably detailed analysis of the UN IPCC’s Special Report on Emission Scenarios and the critique of those scenarios by former Australian Statistician Ian Castles and former OECD Chief Economist David Henderson. Castles and Henderson claim the IPCC has exaggerated the likely extent of economic growth betweeen now and the year 2100 in at least 2 of its 4 “scenario families”.
Now John Quiggin has also joined in with a preliminary and partial analysis of the Castles/Henderson critique. This accumulation of blogger attention has shamed me into doing the legwork and carefully reading both the IPCC’s Special Report and the Castles/Henderson critique. Slightly to my surprise, I find myself at least partly agreeing with both John Quiggin and Ken Miles, although my ultimate conclusion is, I suspect, quite different. Stephen Schneider, the father of the global warming theory, once said “To capture the public imagination, we have to offer up some scary scenarios, make simplified dramatic statements and little mention of any doubts one might have. Each of us has to decide the right balance between being effective, and being honest.” As we’ll see, when looked at in total, the IPCC’s emissions scenarios are a classic example of wholesale adoption of the propaganda technique Schneider advocated. Ken Miles argues that the IPCC scenarios present a wide range of possible futures, and concludes that “in all likelihood, reality will fall somewhere in-between them“. However, although the IPCC does indeed present a wide range of scenarios (no less than 40 of them divided into 4 broad “families”), all of them are distorted by a variety of exaggerated assumptions carefully designed to achieve CO2 emission outcomes much higher than can be justified by existing evidence and research.
The two “scenario families” with which Castles and Henderson take issue, A1 and B1, are both avowedly based on assumptions of “very high” economic growth during the 21st century. The underlying assumptions for both these families are that wealth/standards of living in the developing world will converge with current (i.e. late 20th century) first world standards. Castles/Henderson simply claim that the A1 and B1 families assume excessive growth in the developing world, especially Asia. They argue this on the basis that the IPCC exaggerates the current wealth gap between the first and third worlds by comparing GDP using exchange rates rather than the better accepted ‘purchasing-power parity’ (PPP) basis. The latter basis tends to show a considerably smaller gap between the first and third world than the former. Hence, Castles/Henderson argue, the IPCC has somewhat overshot its avowed aim of modelling convergence between third and first world living standards. They might well be correct, I’m simply not equipped to judge. John Quiggin summarises the debate in the following terms:
The real substance of Castles criticism is that he expects growth to slow down substantially relative to the period since 1950.. He says
The maintenance of an average rate of growth of 2.8 per cent per annum in the output of goods and services per capita for a 60-year period would in itself be an extraordinary achievement. This is double the average rate of 1.4 per cent annually in per capita output which was achieved during the period 1850-1990 (Angus Maddison, The World Economy: A Millennial Perspective, OECD 2001, pps. 264-65), which was in turn about 20 times the estimated rate of growth in per capita global output during the eight centuries from 1000-1820
But of course, growth since 1950 has been substantially faster than than for the period 1850-1990 as a whole. In estimating likely growth for the period 1990-2050, experience since 1950 seems a lot more relevant than for the period 1850-1950, let alone 1000-1820.
No-one can predict with certainty, but the IPCC estimates don’t seem noticeably different from those used in other long-range forecasts.
I’m not familiar with other long-range forecasts so I can’t really comment. However, I’m not sure that John Quiggin is accurately summarising the “real substance” of the Castles/Henderson critique. It is, as I’ve explained, that assumed growth rates in Asia and developing nations are excessively high. Castles/Henderson don’t take issue with growth assumptions for the first world, as far as I can see. If we look at the IPCC’s own material, you can see what Castles/Henderson mean. If you look at this page of the IPCC report, you’ll see that Table 4.5 shows economic growth in Asia averaged 6.4% per annum between 1950 and 1990, and the developing world 4.8% per annum. The A1 scenario family projects Asian economic growth of 6.2% pa between 1990 and 2050, and developing world 5.5% pa. Clearly both scenarios are assuming sustained very high growth in both these regions over a quite long period. However, that is precisely what the IPCC presents them as: – very high economic growth scenarios. However, Table 4.7 presents comparisons based on per capita income (rather than total national economic growth). Asian per capita income growth between 1950 and 1990 averaged 4.4% pa. The A1 scenario projects per capita income growth for Asia at 5.5% pa and B1 at 4.7% pa between 1990 and 2050. For the developing world, the actual 1950 -1990 figure was 2.7% pa, but the IPCC projects 4.9% between 1990 and 2050 in its A1 scenario and 4.2% in the B1 scenario. Looked at in this way, these scenarios do look rather excessive, to say the least.
However, whether the A1 and B1 scenarios should be characterised as just “very high” economic growth, as the IPCC itself presents them, or excessively high, as Castles/Henderson argue, seems to me rather less important than looking at the picture of the scenarios as a whole. There are 4 scenario families (A1, A2, B1, B2), each consisting of 10 separate “stories” comprising slightly different assumptions within the generally-applying “family” storyline assumptions. Chapter 4 of the IPCC report contains an overview of the scenario family assumptions. In summary:
The A1 storyline is a case of rapid and successful economic development, in which regional average income per capita converge current distinctions between “poor” and “rich” countries eventually dissolve. The primary dynamics are:
– Strong commitment to market-based solutions.
– High savings and commitment to education at the household level.
– High rates of investment and innovation in education, technology, and institutions at the national and international levels.
– International mobility of people, ideas, and technology.
The A2 scenario family is a much lower economic growth scenario than A1. It represents a differentiated world. Compared to the A1 storyline it is characterized by lower trade flows, relatively slow capital stock turnover, and slower technological change. The A2 world “consolidates” into a series of economic regions. Self-reliance in terms of resources and less emphasis on economic, social, and cultural interactions between regions are characteristic for this future. Economic growth is uneven and the income gap between now-industrialized and developing parts of the world does not narrow, unlike in the A1 and B1 scenario families.
The A2 world has less international cooperation than the A1 or B1 worlds. People, ideas, and capital are less mobile so that technology diffuses more slowly than in the other scenario families. International disparities in productivity, and hence income per capita, are largely maintained or increased in absolute terms. With the emphasis on family and community life, fertility rates decline relatively slowly, which makes the A2 population the largest among the storylines (15 billion by 2100). Global average per capita income in A2 is low relative to other storylines …
The B1 storyline also assumes high economic growth, although slightly lower than A1. The central elements of the B1 future are a high level of environmental and social consciousness combined with a globally coherent approach to a more sustainable development. Heightened environmental consciousness might be brought about by clear evidence that impacts of natural resource use, such as deforestation, soil depletion, over-fishing, and global and regional pollution, pose a serious threat to the continuation of human life on Earth. In the B1 storyline, governments, businesses, the media, and the public pay increased attention to the environmental and social aspects of development. Technological change plays an important role. At the same time, however, the storyline does not include any climate policies, to reflect the SRES terms of reference.
The B2 storyline, like its A2 counterpart, presents a lower economic growth scenario. The major difference from A2 is that B2 assumes world population growth to 10 billion people by 2100, whereas A2 assumes an astonishing 15 billion (see below). The B2 world also is one of increased concern for environmental and social sustainability compared to the A2 storyline. Increasingly, government policies and business strategies at the national and local levels are influenced by environmentally aware citizens, with a trend toward local self-reliance and stronger communities. International institutions decline in importance, with a shift toward local and regional decision-making structures and institutions. Human welfare, equality, and environmental protection all have high priority, and they are addressed through community-based social solutions in addition to technical solutions, although implementation rates vary across regions.
Current UN mid-range estimates of projected population growth suggest that the world’s human population (currently a bit over 6 billion) will reach around 8.9 billion by around 2050, peak at a little over 9 billion between 2050 and 2070 and then start to decline slowly (you have to infer this from the UN’s graphs, because their projections only extend to 2050). Other credible studies are even more optimistic:
Despite a growth burst that more than doubled the global human population over the past 50 years, a study released today predicts it will peak at 9 billion by the year 2070 and then begin to decline.
“People thought for many years that we would breed ourselves out of existence,” says Warren Sanderson, a professor of economics and history at State University of New York at Stonybrook and co-author of the study appearing in this week’s Nature. “They thought we’d produce so many children, there would be no standing room left on the planet. But now it seems our population will peak.” …
The scientists estimate there is an 85 percent chance the species will taper to about 8.4 billion by the year 2100. The current world population is counted at 6.1 billion.
The reason for these revised projections (which suggest much lower population growth than earlier alarmist reports) is twofold: rapidly declining fertility in the first world, and the ongoing impact of the HIV/AIDS epidemic in the third world.
Therefore, current research shows that the IPCC’s A2 storyline, which assumes a world population of 15 billion by 2100, is patently absurd. It assumes a world population almost twice as high as current research indicates is likely. Thus, while the A1 and B1 scenarios achieve exaggerated CO2 emission outcomes by (at least arguably) exaggerating likely future economic growth, the A2 storyline does so by drastically exaggerating likely population gowth.
The B2 storyline also exaggerates population growth to an extent, in that it assumes a world population of 10 billion by 2100; some 19% higher than current research suggests is most probable. However, that is at least in the ballpark. The A2 scenario is so far outside it as to be laughable. Although there are clearly very large uncertainties involved in projecting future population (just as there are in projecting economic growth), a projection this far in excess of current mid-range estimates is downright dishonest.
An equally important source of exaggeration in the IPCC scenarios is that both the A2 and B2 storylines (the lower economic growth storylines) mostly assume that oil will run out by about the middle of the century, and that third world countries will simply move to (higher CO2-generating) coal as their main source of energy. The B2 storyline at least assumes that the first world will make some efforts to move to cleaner energy technologies (like natural gas). Hence it achieves markedly lower emission outcomes than the A2 storyline, which shows CO2 emissions at stratospheric levels. Essentially it is the A2 storyline that results in the really scary future temperature projections such as claims of temperature rises of 5 degrees C by 2100. All other scenarios, including B2, result in much more modest (though still exaggerated) outcomes (although there are some individual A1 scenarios that also reach stratospheric emission outcomes, again mostly by assuming exhaustion of oil and conversion to coal).
In fact, although current world oil reserves are projected to last around 60 years or so, those reserves figures don’t include the relatively plentiful natural gas reserves (a cleaner fuel than oil). Nor do they include Canada’s oil sands deposits which, at an estimated recoverable 1,700 billion barrels in total, are believed to be larger than Saudi Arabia’s oil reserves.
Even if parts of the world are forced to rely on coal for energy by the end of this century, that doesn’t justify the “business as usual” assumptions inherent in the A2 storyline (and, although to a lesser extent, in the B2 scenarios as well). Efforts are already under way to develop commercially viable methods of generating energy from coal with minimal atmospheric CO2 emissions. The Bechtel corporation is currently in the middle of a 3 year US Department of Energy-funded project to build and test small coal-fired power stations using such technology:
The Department of Energy has awarded a contract to Bechtel National Inc., San Francisco, CA, to study a process that removes carbon dioxide, a greenhouse gas, from the gas streams of future energy plants by converting it to “ice” – or more correctly, into an ice-like hydrate. …
The process is intended to be integrated with future coal gasification systems. Many technology experts predict that coal gasifiers — rather than traditional coal combustors — will form the core of advanced, 21st century, super-clean power plants.
Bechtel is due to complete its study in the next couple of months. The results may be crucially important to future CO2 emissions outcomes. Although oil and natural gas will almost certainly be able to provide the great bulk of the world’s energy needs until fairly close to 2100 (contrary to IPCC assumptions in both the A2 and B2 storylines), commercially recoverable reserves will probably run out towards the end of the century. Although there are various other potential large-scale energy options (including hydrogen fuel cell technology and nuclear energy), coal is likely to remain an important energy source. Recoverable world coal reserves are estimated at greater than 200 years.
The bottom line – ALL of the IPCC scenarios present exaggerated CO2 emission outcomes. The A1 and B1 storylines project exaggerated assumptions about economic growth; while the A2 and B2 scenarios project exaggerated assumptions about world population, fuel sources and technologies. As a result, the IPCC’s projection of possible global temperature rises between 1.5 and more than 5 degrees C by 2100 are simply not credible. As I have observed previously, CO2 emissions have been increasing in a strictly linear fashion for many years now, and a straight line extrapolation of current temperature increases suggests a global temperature increase of only a modest 1 degree C by 2100. The IPCC achieves its “scarier” temperature outcomes only by positing the patently exaggerated emissions scenarios discussed above, and by assuming that the world’s climate system involves net positive temperature feedback mechanisms (even though there is currently no proper scientific basis for making such assumptions).
Despite the IPCC’s efforts at distorting reality, however, its emissions scenarios actually yield a quite surprising result, although you’d never know it from their propaganda emphasis. The most positive CO2 emissions outcomes are actually achieved through fostering strong economic growth, as the following IPCC graph shows. The bold solid lines are the so-called “marker” scenarios for each family. A1 is the red line; A2 the brown line disappearing up into the stratosphere; B1 the green line; and B2 the blue line.
As you can see, the B1 scenario, which assumes high economic growth, but with “a high level of environmental and social consciousness combined with a globally coherent approach to a more sustainable development”, actually yields CO2 emissions by 2100 that are lower than those of today (and falling). And that is without any Kyoto-style proscriptive emissions reduction schemes. The conclusion I draw from all this is that the world should continue pursuing economic growth through globalised trade, which provides the best prospects for the developing world to achieve first world standards and thereby be able to afford CO2 emission reduction measures. We should reject greenie demands for draconian measures to curb growth, technology and industrial development. Those sorts of approaches will have negative results on CO2 emissions, as the B2 storyline clearly shows (steadily increasing emissions, though not as much as A2). By contrast, both high economic growth storylines result in falling CO2 emissions after a mid-century peak.
I’m not suggesting that Kyoto itself is necessarily a bad idea, however. It is a modest initiative, and current research suggests that its adverse effects on economic growth with be very small. Moreover, the establishment of a global CO2 emissions credit trading system, which Kyoto envisages, will create price signals that will help ensure that cleaner technology initiatives like Bechtel’s one discussed above, and hydrogen fuel technology, are in fact pursued in a timely manner. My concern is that greenie zealots will continue using the exaggerated IPCC scenarios to advocate far more draconian and economically damaging measures than Kyoto, and that most people (including politicians and media) won’t bother to do the necessary research to discover that what they’re claiming is arrant nonsense. If you’ve bothered to read this far, then you’re not one of those people!