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As by volume the most relevant renewable fuel standard world wide, a closer look at the details of this regulation is worthwhile - to understand the issues behind decarbonization policies in transport.  The RFS2 details that

"EPA is making threshold determinations based on a methodology that includes an analysis of the full lifecycle of various fuels, including emissions from international land-use changes resulting from increased biofuel demand. EPA has used the best available models for this purpose, and has incorporated many modifications to its proposed approach based on comments from the public, a formal peer review, and developing science. EPA has also quantified the uncertainty associated with significant components of its analyses, including important factors affecting GHG emissions associated with international land use change."

Specific lifecycle GHG emission thresholds for each of four types of renewable fuels were established, requiring a percentage improvement compared to lifecycle GHG emissions for gasoline or diesel. One of these fuels, ethanol produced from corn starch produced at a new natural gas facility using advanced efficient technologies will meet the 20% reduction threshold compared to the 2005 gasoline baseline (says EPA). Other fuels meet the 50% or 60% benchmark.

Iowa harvest 2009 (Bill Whittaker, licenced under GNU free documentation licence)

While the life cycle methodology of the EPA if fairly comprehensive, a few important caveats were noted in a review of the RFS2 by Richard Plevin:

• EPA performs its analysis in a projected 2022 world, assuming a variety of technology changes. This is similar to accounting for today's emissions from coal power plants as if they had implemented anticipated CCS technology. In 2012 all and in 2017 most corn ethanol pathways analyzed by the EPA do not meet the 20% GHG reduction requirement, or even produce greater GHG emissions than the gasoline baseline.
•  In the EPA model corn ethanol achieves productivity gains without additional use of fertilizer. The peak of corn ethanol production is achieved in 2016 -  inducing most ILUC - while productivity assumptions refer to 2022 with additional 9.4% crop yield. Hence, ILUC are systematically underestimated.
•  EPA attributes large soil carbon sequestration to biodiesel, most likely for increased used of no-till. However, no-till may increase N2O emissions (Six et. al). There is uncertainty on this issue, but EPA treats net soil carbon sequestration as a fact.
•  Cellulosic ethanol obtains a low GHG rating by co-product credits generated by electricity from biochemical cellulosic refineries that displaces the average US grid electricity. Taking the average US grid as benchmark is a courageous assumption. More detailed analysis could significantly change the life cycle emissions.
•  An additional supply of biofuels reduces the world market price of petroleum, by this increasing its demand. In one study, the global petroleum effect is estimated to be around 27% implying that each MJ of biofuel replaces 0.73 MJ of petroleum (Stoft, 2009). Hence, biofuels that are less then 27% below gasoline baseline could have a net positive global warming effect. This effect is acknowledged but not modeled by EPA.

In summary, EPAs carbon accounting should be taken with some care. In particular, today's corn ethanol may have higher than baseline gasoline GHG emissions (e.g., Hertel et al., 2010). By focussing on potential 2022 technologies, this emission disbenefit is insufficiently reflected. Some policy maker pressure the EPA with respect to corn ethanol, arguing that corn ethanol production decreases energy independence and produces jobs. However, from this perspective, pro-corn ethanol policies should be designed from the perspective of jobs and energy independence, rather than using the RSF2 as camouflage.

References

Hertel, T. W., A. Golub, et al. (2010). "Global Land Use and Greenhouse Gas Emissions Impacts of U.S. Maize Ethanol: Estimating Market-Mediated Responses." BioScience 60(3): 223-231.

Plevin, R. J., M. O'Hare, et al. (forthcoming). The greenhouse gas emissions from market-mediated land use change are uncertain, but potentially much greater than previously estimated, UC Berkeley.

Six, J., S. M. Ogle, et al. (2004). "The potential to mitigate global warming with no-tillage management is only realized when practised in the long term." Global Change Biology 10(2): 155-160.

Stoft, S. (2009). "The Global Rebound Effect Versus California's Low-Carbon Fuel Standard"    

Carbon dioxide is not the only greenhouse gas. Coemitted air pollutants also significantly affect global climate. By various interactions, their absolute effect can be complicated to evaluate. In principle, however, most air pollutants have a relatively short time span in the atmosphere, and hence, can be classified as short lived species. Many air pollutants, including organic aerosols have a global cooling effect, whereas black carbon and ozone contribute to global warming.  The effect of the short lived species is not marginal. In fact, their combined radiative forcing may outweight that of carbon dioxide (Forster et al., 2007). In view of this observation, there is increased attention on the mitigation potential of some air pollutations, such as ozone and black carbon, short lived species with high radiative forcing. On the other hand, there are other aerosols, excluding black carbon, which exert a cooling effect that may have masked about 50% of the global warming by GHG. The fight against air pollution and for public health can, hence, have an unwanted impact by inducing accelerated global warming. Starting with this background, Unger et al. from NASA ask in PNAS in their article Attribution of climate forcing to economic sectors the following question: How is the total radiative forcing effect organized according to economic sector, the drivers of emissions?

The authors point out that emissions of black carbon (positive RF) and organic aerosols (negative RF) are often coupled. Hence, the ratio between both emittants is important to evaluate the total radiative forcing in a specific sector. An analysis of sectors according to this ratio reveals significant differences across sectors:

•  There are sector such as the power industry that have high emissions of species with both positive and negative radiative forcing.
•  Other sectors, such as road transport, are dominated by species with positive radiative forcing. More specifically, the ratio between black carbon and organic carbon aerosols is relatively high in road transport.

The accumulated climate impact over all sectors is visualized in the figure below (Source: Unger et al., 2010). In fact, in the short term (2020), road transport dominates the accumulated climate impact. In the long run (2100), the power sector dominates as greenhouse gases persists significantly longer in the atmosphere than short lived species.

Climate impact of economic sectors in 2020 and 2100.

From this technical analysis, effective  climate change mitigation can most easily be obtained in on-road transportation - with significant co-benefits as air pollutants from transport are more harmful than from other sectors. This is for example due to a higher intake fraction (fraction of pollutants that is inhaled, e.g. Marshall et al., 2005), but can have more general benefits for public health and overall mobility (Creutzig and He, 2009). However, from a climate perspective road transportation is underregulated. For example, in Europe road transport is not part of the emission trading scheme, and, by this, is positively discriminated against electrified rail transport. A clever mix of instruments that prices the harmful parts of mobility while increasing its beneficial aspects (e.g. accessibility, thence, could have a near and long term positive impact).

Thanks to Jan Minx for pointing out the PNAS article.

References

Forster P, et al. (2007) Changes in Atmospheric Constituents and in Radiative Forcing, in Climate Change 2007: The Physical Science Basis, Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, eds Solomon S, et al. (Cambridge Univ Press, New York)

Unger, N.,  Bond, T. C., Wang, J. S., Koch, D. M., Menon, S., Shindell, D.T., Bauer, S. (2010) Attribution of climate forcing to economic sectors PNAS 2010 : 0906548107v1-6

Marshall, J.D., Teoh, S.K., and Nazaroff, W.W. (2005) Intake fraction of nonreactive vehicle emissions in US urban areas. Atmospheric Environment 39 (7), 1363

Creutzig, F. and He, D. (2009) Climate change mitigation and co-benefits of feasible transport demand policies in Beijing  Transportation Research D 14: 120-131

"Global Sustainability - a Nobel Cause", is the title of a book that just has been published by Cambridge University Press. A number of nobel price winners and eminent scientists in sustainability research gathered to write up their thoughts on sustainability. This book certainly does not fulfill coherent scientific standards (peer-reviewed, novel insights) but is very promising in bringing some relatively simple but profound thoughts together. Also, as a clear pro: this book is freely available online, and individual chapters can be downloaded as pdf.

What can we, then, learn from this book? Let us start with Geoffrey West's observation that current scientific endeavors have, to a large degree, failed to come to grips with the essence of the long-term sustainability challenge: the pervasive interconnectedness and interdependency of energy, resources, environmental, ecological, economic, social, and political systems (West, 2010; see also Creutzig and Kammen 2009). My own specific example of this statement (Creutzig and Kammen, 2010) looks at the specific examples of biofuels, rephrasing the by now established view that a simple-minded view of biofuels as zero-carbon sources of energy misses the point, as a) the carbon content can be not only significant but even surpassing that of conventional fuels and b) a number of additional sustainability issues such as biodiversity loss, deforestation and food insecurity threaten to diminish any feasible positive impact on the climate change front.

So what is the possibility and challenge of using a coarse-grained systemic approach that builds on, but also goes beyond, piece-meal wise investigations? Wolfgang Lucht calls for the enterprise to construct new mental images of the whole - or taking a crude look at the whole as Murray Gell-Mann says - that must be founded in rational analysis and, equally important, cultural production (Lucht, 2010). In fact, according to Lucht, a controlled transition in the interlinked social-environmental world system is to be achieved, only by making transitional progress not just in the environmental domain, where the impacts have to be lessened, but also in the social domain, where the problems have their origin. This transitional progress building on rational-scientific insights (that transcend the techno-economic totalitarian aspects of enlightenment) then could enable a sustainable transition path as depicted in the figure below.

(taken from Lucht, 2010, partially based on Schellnhuber, 1999) 

The small problems left are (1) to fill these grand themes with contents and (2) to integrate the findings into the "societal self constructions that dominate human processes" (Lucht, 2010). Regard the first issue, my blogging colleague Carey King suggests to look at EROI - energy return on energy invested -, noting that EROI is lower for renewables than for fossil fuels with respect to human time scales, and that a future lower EROI implies a reduction in societal complexity (this conjecture requires more thoughts though). Geoffrey West points at the fundamental nature of time scales, explaining the supra-linear scaling of agglomerations, and hence supra-exponential growth that requires an ever accelerating rate of innovation (not sustainable). These spotlights indicate the pressing need for a consistent growth theory which includes natural capital degradation (and appropriate ressource flow exploitation), agglomeration dynamics and structural change, the clear definition of a perspiciuous welfare function of sustainability, and finally a proposal for a non-catastrophic deceleration of the human socio-economic system.

References

Bettencourt, L. M. A., Lobo, J., Helbing, D., Kühnert, C. and West, G. B. (2007) Growth, innovation, scaling, and the pace of life in cities. Proceedings of the National Academy of Sciences of the United States of America, 104(17), 7301- 6.

Creutzig, F.,  Kammen, D (2009) The Post-Copenhagen Roadmap Towards Sustainability: Differentiated Geographic Approaches, Integrated Over Goals INNOVATION, Vol 4 (4): 301-321

Creutzig, F.,  Kammen, D (2010) Getting the carbon out of transportation fuels. In H. J. Schellnhuber, M. Molina, N. Stern, V. Huber & S. Kadner (Eds.), Global Sustainability - A Nobel Cause. Cambridge: Cambridge University Press, UK.

Schellnhuber, H. J. (1999). Earth System Analysis and the Second Copernican Revolution. Nature 402, Suppl., C19 - 23.

West, G. (2010) Integrated sustainability and the underlying threat of urbanization. In H. J. Schellnhuber, M. Molina, N. Stern, V. Huber & S. Kadner (Eds.), Global Sustainability - A Nobel Cause. Cambridge: Cambridge University Press, UK.

Prices of solar energy and wind turbines are dropping world wide. This article in the New York Times highlights the role of China in this market. The bottom line is as follows: China by now is the world leading manufacturer of solar panels and wind turbines. By this is achieves economics of scale and can offer products at a relatively low world market price.

There are two immediate consequences:

1. Installation of renewable energies becomes cheaper worldwide 
2. Manufacturing competitors in other countries have a tough stand competing against Chinese manufacturers

Why could China get into this position in first place? The NYT article delivers the following explanation:

"China's biggest advantage may be its domestic demand for electricity, rising 15 percent a year [...] In the United States, power companies frequently face a choice between buying renewable energy equipment or continuing to operate fossil-fuel-fired power plants that have already been built and paid for. In China, power companies have to buy lots of new equipment anyway, and alternative energy, particularly wind and nuclear, is increasingly priced competitively."

In other words: in the US and Europe, renewable energies have to compete against existing energy supply, in China they don't have to: there is enough space for both rapid expansion of coal power plants, and renewable energy. Practically unlimited demand requires expansion of energy supply across the board. Another reason the low prices, of course, is the lower labor costs in China.

An interesting exercise is to consider the consequences of this observation the other way around. If saturated economies decided to phase out conventional power plants - coal and nuclear - rapidly, there could be room for economies of scale in renewable energy supply locally, too. However, such a decision can only be made politically as those who would massively invest into renewable energy supply are the current owners of existing coal plants.

Understanding the dynamics of this game (and the relevance of the argument above) is of high relevance for OECD countries. For example, in Germany the phase-out of nuclear plants is renegotiated, with stakeholder arguing that longer running time of nuclear plants serves as a 'bridge' towards a renewable energy future. From a different perspective the nuclear power plants pose a barrier towards economies of scale in renewable energy supply with the two consequences of (a) losing an edge advantage in international economic competition in renewable energy technologies and (b) getting the intertemporal optimization wrong. The intertemporal optimization point is that investing now into renewable helps to get the prices down quicker, and have lower abatement costs in the future (this argument is so central that is deserves another blog).

The debate pro/con nuclear power from the climate perspective is still open. The Chinese evidence of the economies of scale, however, provides some quantitative indication in favor of phasing out conventional plans rapidly. 

How do we get land transport on the track towards sustainability?

This was one of the questions of last week that witnessed intense and exciting exchange at the Transport Research Board, and a special conference on Transforming Transportation in Washington, D.C. From a climate perspective, sustainable translates into low-carbon transportation. However, sustainable transportation also comprises equity and accesssibility, public heat, such as air pollution and noise but also effects related to physical activity, and time and monetary cost of transportation.

Land transportation is responsible for 5-30% of greenhouse gas emissions of countries. Currently, transport's share of GHG emissions is signficantly lower in developing countries than it is in OECD countries, notably the U.S. However, emission growth is heading north. Sustainable transport policies are not incredibly challenging to understand. They include pedestrian facilities, a network of well maintained bicycle lanes, parking facilities for bicycles, a bus or tram network for medium sized city, and an additional subway/metro network for larger cities and metropolitan regions. Crucially, non-motorized transport and public transit must have priority before car transport wherever these modes struggle for space. The spatial dimension is indeed the most interesting and challenging: what is the optimal land-use policy related to sustainable transport? When facilities, jobs and residential areas are well connected to public transit, sustainable modes of transport can guarantee accessibility. Now, sustainable transport is less expensive than building highways but it still must be financed. Let's look at the financial flows of the development banks as of 2007 (Figure below).

adb.png

Source: ADB, 2009

·            The World Bank and the Asian Development Bank commit about three fourth of their transport lending towards roads and highways (ADB, 2009). There is basically no funding for pedestrian and cycling infrastructure.

·           More generally, multilateral development banks still fund dirty projects (fossile fuel related) with 4 times more money than green projects. Bilateral agencies are only little better (Hicks et al., 2008; for some further discussion and data see Creutzig and Kammen, 2009)

·            According to a former Bank member, the World Bank never funded a pedestrian project. One proposed project was rejected, as the financing volume was too small.

When financing of sustainable transport projects increases sustantially, a huge number of projects could be funded as bycicle lanes, but also bus rapid transit systems are not incredibly expensive. Of same importance is the reduction of conventional projects, such as highway construction. In transport, infrastructure supply induces demand, and additional road network will increase automobile dependency, can even lock-in developing countries into car dependency as it happened before to other countries. Hence, a goal from the top-down perspective is to inverse the factor 4 in financing: 4 times more money into sustainable road projects than into road construction (certain projects probably still make sense). As banks and donors work mostly with large chunks of money, but also as sustainable transport projects work best in a system's approach, it is in many cases best to bundle projects into city-wide packages.

As a side note: The factor 4 also finds itself in the paper of the TRB conference last week. A simple word search in TRB papers found approximately 4 times more hits for highway (1822) than sustainable (337), and cars (1822) versus pedestrians and bicycles combined (495). Science needs to switch, too.

ADB, 2009. Rethinking Transport and Climate Change. Working paper series.

Hicks, R., Parks, B. C., Roberts, J. T., & Tierney, M. J. (2008). Greening Aid? Understanding the Environmental Impact of Development Assistance. Oxford, UK: Oxford University Press.

F. Creutzig, D. M. Kammen (2009) The Post-Copenhagen Roadmap Towards Sustainability: Differentiated Geographic Approaches, Integrated Over Goals
INNOVATION, Vol 4 (4): 301-321

Why did Copenhagen end in a disaster? Of course, there are a multitude of reasons. The negotiations were not well prepared, the personal dynamics did not work out very well. A major point is probably that the negotiations were overloaded with too much content and too high complexity. Consider for example that a global cap requires binding commitment from 193 countries, or at least of 17 countries that emit more than 90% of all greenhouse gases. If one country, for what reason whatsoever, does not agree to its "appropriate share" (assuming for the moment that such a share can be determined), then other countries will have reduced incentives to stick with their original commitments. A simultaneous global monetary transfer does not simplify matters.

Beyond these general issues it is very clear that the global powers failed in assuming their respective responsibilities.

European Union. The European Union was close to upscale its commitment of 20% reduction from 1990 till 2020 to 30% or 40%. As a coal dependent country, Poland blocked this target. However, it is also a sign of weak leadership of Merkel, Sarkozy and Brown that they could not forge a deal with Poland. Germany embarrassed itself with its new minister of development, Dirk Niebel, who wants any climate fund not to be additional of existing development aid.

United States: The United States could not agree to any numbers. The major problem, of course, is the US Senate where a 3–4% reduction until 2020 (with baseline year 1990) is still up in the air. Hence, Obama could not even commit to this low number. Furthermore, the financial contribution for adaptation in the world's poorest nations is not more than a third of that what the EU and Japan committed each for 2010–2012. Here, Obama could have shown much more leadership. Somewhat worrying is the discourse within U.S. media, providing the playing field for disappointing US policies. The scope of the overall challenge is rarely mentioned. In the New York Times, some hacked e-mails were blown up to a big story without getting the context right. As a result of wildly fragmented story lines, it is possible that a significant minority of US senators considers climate change to be a scam.

China

By now China is the world largest GHG emitter. Without China, there is no solution. China displays some political will in reducing the carbon intensity of it economy. However, China does not agree to a binding cap while it would have financial resources at hand to realize ambitious measures. China played a very self-confident role in Copenhagen, and wants to be understood as a global leader. However, for a global leader one ingredient is missing: assuming responsibility (see also the US and the EU).

Enough of the blame. Let's look for a way out of this mess. One big problem is that the discussion was framed in terms of burden sharing, money to be paid, and economic loss. This is the facile view of the story.

There is also another, bright perspective. It is bottom-up, as pointed out by Californian governor Arnold Schwarzenegger, and Nobel prize-winner Elinor Ostrom. Let us look at the specific perspective of the above mentioned world regions (real action probably has to come from communities, climbing up the political decision-making ladder).

Consider that a first mover towards ambitious emission reductions will gain also most of the resulting economic advantages (results of a meta-study called RECIPE). There is a clear rationale for, e.g. the EU, to commit to more ambitious targets.

The US would profit enormously from emission reductions, notably gaining energy independence. Super-costly wars in the Middle East would not be necessary anymore. This would free scarce US resources, e.g. for guaranteeing safe trade routes in world oceans – much more rewarding for the US and the world.

China has to gain a lot from reduced coal consumption. China is still the world's air pollution haven with hundred and thousands of fatalities every year. As a result, life quality is not even closely growing with GDP. In fact, there are a multitude of co-benefits for local or regional sustainable policies.

Fortunately, many citizens and politicians understand that climate change mitigation can increase social welfare, also locally. We need to work hard to realize such policies as soon as possible.

While climate-change negotiation is mostly about absolute mitigation targets, and the money flow between countries, more specific policies appear under the code word of NAMAs (nationally appropriate mitigation actions), and at various side events of research institutions and international agencies. Beside avoiding deforestation, transportation is one of the crucial issues.

Here is why: in Europe, a cap exists for industry and the electricity sector but not for the transport sector. In fact, emissions from the transport sector are rising. There is no chance that Europe will meet any ambitious post-2020 Kyoto targets without reigning in emissions from the transport sector. The same is true for US, where emissions from transport constitute an even higher percentage of overall emissions.

Emission-wise of higher importance is the rising affluence and motorization of Asian cities. While currently car ownership is relatively low, the bulk of upcoming individualized motorization is expected to come from developing countries, at least doubling the current number of cars on the road, from 1 billion to 2 billion.

What can be done about it?

Let's start with the OECD perspective, particularly EU/US. A presentation by Ottmar Edenhofer from the Potsdam Institute of Climate Impact Research (PIK) and myself addressed the question of how to set a cap on transport emissions, and potentially include transport into an intersectoral emission-trading scheme. "Broad is beautiful" in the sense that increasing coverage decreases abatement costs – even if a high-cost sector joins the scheme – and is superior to separate emission trading schemes. However, as also pointed out by Bracken Hendricks, from the Center of American Progress, and Thomas Becker, head of policy relations of BMW, complementary policy instruments, such as fuel efficiency standards, are required to realize abatement in transportation.

For low-carbon development in Asian cities, the community focuses on the so-called Avoid-Shift-Improve approach. Of particular importance is the "avoid" part here: the dense urban fabric shall simply be retained and modernized but not erased in favor of broad motorways (presentations on this topic, including my own, can be found here). This automatically favors the most environmentally friendly modes: walking and cycling. In this sense spatial planning, and clever land-use taxation, can provide multiple benefits, from climate change mitigation to improved accessibility, and reduced air pollution. Such measures work best as part of policy packages, i.e. together with investments in public transit, and restriction of car use. Half-baked measures will not work. It is not clear how the benefits of these policy packages can be quantified, and be included in some sort of extended policy CDM. Perhaps, one should rather focus on capacity building and leveraged financing and grants via international funding agencies.

In the side-event of the 'Bridging-the-Gap' initiative, whose purpose is to get transportation into a post-Copenhagen treaty, climate ambassadors from Costa Rica, South Africa, France and South Korea gave excellent statements on their perspective on transort and climate. As a highlight the chief negotiator of Costa Rica explained the transport issue in depth, emphasizing the status dimension of the automobile. In fact, on their way to carbon-neutrality in 2021, Costa Rica understands the transport sector to be the major challenge.

Can pneumatic cars, aka compressed-air cars, contribute to sustainable mobility? The answer is a clear no, according to our model that was published last week in Environmental Research Letters.

Compressed-air cars have been heralded as the saviour of mobility by a small but vocal community for the last decade. Focal point of this community are regular press releases of Motor Development Internationa (MDI), a French company with an US branch, announcing every few years the soon deployment of their compressed-air cars that have wonderful properties such that range above 1000 km, rapid refilling, and low costs of charging. There are also other small business such as Energine and K'airmobiles that claim to develop compressed-air cars. The press releases were positively reflected in a few newspaper articles in the Anglo-Saxon world, and reverberated then in a small but enthusiastic community.

Of course, there is some truth in the compressed-air story. Tram lines at the end of the 19th century were running on compressed air (the compression was powered by coal, so not so much the clean solution). In principle, it is valid technology, but not so much in practice.

Our paper shows that the MDI claims are nonsense. Let me shortly rephrase the argument here. In a compressed-air car (CAC) air is the storage medium. A compressor is needed to store air at high pressure in a tank. The air motor is then driven by the expansion of air. In that regard, a CAC is more a less equivalent to an electric car – but with compressed-air as storage medium instead of a battery. Now the point is: a battery is just significantly more efficient than the compressed-air storage. Thermodynamics are not to the advantage of the CAC. This translates into very poor economic and environmental performance. Furthermore, huge tanks would be needed (780l tank for a cruising range of 115 km).

So if you want to run your car on electricity – use battery as carrier technology. If lithium becomes a scarce resource, hydrogen produced by electrolysis would still be the more efficient option.

The ERL paper was immediately perceived in a range of auto-blogs, starting with the New York Times, receiving hundreds of comments. Many comments were up to the point. Others were very sceptical of the paper, e.g. "I'm a strong believer that this article is a bunch of BS. Or more specifically, oil-industry-speak. India auto-maker, TaTa Motors has many orders backed up for a compressed-air car that they build. London is waiting for 500 taxis. It will run for up 300 miles on one filling of the carbonfibre tank. The compressor comes with the vehicle and you install it in your garage. It runs on your local household current."

Now, it's nice to learn that I am a big fan of the oil industry. There is too much opinion on this topic, not sufficient analysis, on both sides. The enthusiasts do not care to do even some back-on-the-envelope calculations, and the critics of the CAC come up with talking points like "Air cars are hot air", which is not up to the point either: air cars are more than mere mind games – and actually run on cold air (look up some thermodynamics).

If you want to test your own set of assumptions of the CAC, you can download a spreadsheet model here. On that side, you can also find a link collection to blogs' discussion of the CAC paper.

F Creutzig, A Papson, L Schipper, D Kammen (2009) Economic and environmental evaluation of compressed-air cars. Environ. Res. Lett. 4 044011.

On Saturday, more than 5200 events took place worldwide, all of them promoting the number 350: understood as the upper limit for carbon dioxide in the atmosphere. We are already above. The slideshow on the website gives an amazing display of actions that took place. Altogether, the action day seems to be a huge success, mobilizing an incredible number of people and raising awareness.

For example, in Berlin several hundred people, climate pirates, gathered, all disguised as Angela Merkels to push the German chancellor towards progressive climate policies.

This and similar actions were reported by newspapers all over the world. Andrew Revkin of the New York Times gives voice to critical opinions who point out that the number 350 is unrealistic and only promotes fatalistic attitudes. Others think that focus should be on ways towards climate protection rather than arguing over numbers.

Both opinions are justified but, to some extent, miss the point.

Given the risk of very high damage to humanity, it is a questionable attitude to aim for a target that leaves Bangladesh drowned, so to speak. In fact, this is itself a fatalistic position which seems intellectually hard to justify. Though the 350 target is very ambitious, it might be not impossible. The two camps arguing for either 350 ppm or less ambitious targets are motivated more by belief systems that frame model assumptions rather than hard facts – and it may be impossible to know precisely.

It is true, that the 350 campaign provides no precise solutions. However, you can probably ask any climate activist, and she or he can come up with a list of legislation and actions that lead the path towards climate protection. There is not so much a knowledge barrier ¹, but there are political barriers. In the words of the current US president in the context of the current US climate legislation (also this Saturday): "The closer we get, the harder the opposition will fight and the more we'll hear from those whose interest or ideology runs counter to action."

He also gets the fatalistic thing right: "There is also another myth we must dispel, And it is one far more dangerous than any attack made by those who wish to stand in the way of progress – and that's the idea that there is little or nothing we can do.

"That is the pessimistic notion that our politics are too broken and our people too unwilling to make hard choices. Implicit in this argument is the sense that we've lost something important   that fighting American spirit, that willingness to tackle hard challenges and the determination to see those challenges to their end."

The point of the 350 campaign seems to raise awareness and increase political pressure towards action, and that may be exactly the right thing to do.

There is still an argument against the 350 number: It is a number!

Number target are always one-dimensional and reduce complex circumstances to something overly simply. Focusing on narrow numbers invites gaming behaviour, i.e. where agents just head for numerical targets, and ignore the context. For exam ple, we don't want to protect our climate by clouding our skies with air pollutants. In other words, it is not only about ppm levels, it is about sustainability. In that sense, leaving space to live for happily raging sea otters may be alright, too.

_{(1) and neither are cost the real barrier, but this is a different issue}

Back in Beijing. On first appearance, things (read 'Transportation') didn't change very much since spring 2008. That is a surprising statement. It means that congestion as perceived by the casual observer didn't detoriate - it even looks acceptable at most times during the day. A Beijing success story?

Beijing implemented a number of measures for the Olympic Games to deal with congestion and air pollution. That included an alternate driving ban based on odd/even numbers, effectively excluding half of the vehicle fleet every day. To no surpise the congestion situation improved dramatically during the Games. Due to this success, some of the measures were continued, modified or extended:

• Ban of cars according to licence plate number once a week • Parking management (from 1 Yuan/hr outside of the 4th ring to 5 Yuan/hr for the 'affluent' neighbourshoods inside the 4th ring • By now 650 bus routes, >250 km bus-only lanes, 200km subway with 6 lines, and 3 BRT lines • Car free day (but forget that one: 2 streets are to be closed on Sep 22).

Beijing added subway and BRT routes

According to BJTRC, peak hour speed increased by 2-3 km/h, and the congestion index decreased from 7.54 to 5.15 (a scale from 0-10, where 10 is worst congestion and 0 zero congestion; the index is calculated as as nonlinear function of the percentage in time where streets are below a certain congestion speed - 20km/h for Expressways, 15km/h for secondary roads, and 10km/h for collectors). Such an improvement translates into billions of Yuan per year in time savings. The real savings/social benefits depends on the opportunity costs of those who can't drive their car due to the ban. Can they work at home? Can they easily switch to public transit, or car pool? A pricing instruments, such as a city toll for Beijing would be more efficient according to economic theory, but a full accounting of transaction and opportunity costs might reveal that a car ban is not such a bad thing in economic praxis. It's not a long-term measure, however, as rising car ownership overcomes the driving ban by sheer numbers.

Public transit, i.e. bus plus subway increased its modal share from 30.2% to 36.6%, thus absorbing nearly all additional transport demand (4 million more trips per day). However, the number of car trips also increased. Hence, there is probably not much of a modal shift from car to public transit. At least some additional car transport may have been avoided.

There are currently two issues that need more attention: land-use and NMT (non-motorized transport). Land-use means the construction of new satellite cities, their distance to work places, and work place distribution. For non-motorized transport the big problems are safety, and barriers. Whereas Beijing has separate broad bike lanes along many roads, crossing of big arteries is a huge safety issue and many people cite this as their number one reason for not cycling. Also, at some streets its difficult to find a suitable crossing - hence streets/expressways constitute a considerable obstacle for pedestrians and cyclists. Much to be done - but Beijing is on the right track.