The expert on lifestyle dynamics from the Potsdam Institute for Climate Impact Research sees personal consumption behaviour at the heart of the climate change debate.

Q1) So far the international discussion on climate change has concentrated on two components: economic aspects and technology. Yet you as an expert for lifestyle dynamics stress the importance of consumption behaviour. Why is consumption behaviour of single households and citizens so important for sustainable success?

Forty percent of the emissions causing climate change come from private households and depend on their behaviour. Important questions to ask are: what mobility pattern do I have, what house, what heating system, and what food do I eat, is it a meat-rich diet? And all those decisions which have to be made in households contribute to how much we emit. Additionally, the choice of households with respect to consumer goods is crucial. Thus, if you consider this, you can see that consumer behaviour is really important. It is not everything but if we miss out on it, we will loose an important opportunity in the fight against climate change.

And we can not miss a single opportunity because there is no silver bullet for climate policy. That is the difference to the ozone problem which was about a bunch of chemicals and a selected number of chemical producers. You switched those firms to other products and you were done. Climate is a completely different case because everybody is contributing to it in various ways and there is no single solution. Instead of CO2 we now emit X – that is impossible. Instead we now have to switch in all areas, from food to different technology to different behaviour.

Q2) You already mentioned some domains in day-to-day life where a more climate-friendly behaviour can have a positive impact. What kind of comprehensive lifestyle is needed to substantially reduce emissions?

First of all, at the end of the day all is measured all in CO2 which has to be reduced. Secondly, there are different ways to do so because people have different domains in which they might be very carbon-intensive or not. One could argue that if you can not avoid flying and you also can not compensate that, you should invest more in reducing housing energy. Or if you are a meat-lover you might think about your travel behaviour. So there is some flexibility. Again there is no such thing as one single lifestyle which one could recommend. Of course it would be best if you could reduce emissions in all these dimensions but you need support.

For example, if you want to switch to renewable energy in your household, there has to be renewable energy available at an affordable price. But this is not the problem. It is also rather a mental problem. Astonishingly although the price difference is not that large, very few people in Germany switch to green energy. In part this has to do with information uncertainty. But the more people switch and the bigger those companies become, the less the problem will prevail.

Q3) But how big would the positive impact on the environment be, if every citizen changed to a more sustainable lifestyle?

This is a scientific question: how much can we emit without damaging the climate? There is a consensus that two degrees warming compared to pre-industrial level would be an acceptable degree of climate change. In order to meet this goal you have to calculate back emissions.

So if every person on this planet had an equal right to pollute - which today is still very unequal - and we assume some population growth, we would end up with a maximum of two tons emissions per capita per year in 2050. So where do we stand right now? This very much depends on the countries and the personal lifestyle. On a country-level we have about 10.8 tons emissions per capita per year in Germany, twenty tons in the United States, four tons in China, one ton in India and less than one in Africa.

Thus, most of us except for the Indians and Africans will have to cut down their emissions. In the case of the United States it is dramatic. In the case of Germany it is a fifth. That is what we need and this is why changing a light bulb here or insulating a house there will not be efficient.

What we need is a third industrial revolution - and as part of this an adaptation of our behaviour and our lifestyles.

Q4) But in a modern industrial society like Germany is there not already a value-change towards a more green, low-carbon society?

Yes, starting with measurable facts again, Germany is one of the very few countries that has managed to reduce its carbon footprint. We have met our Kyoto goal and Germany has contributed to more than half of the total reduction of the European Union. Most of the European Union member states like Spain, Greece and Ireland have been assigned under the Kyoto reduction goal additional CO2 emissions.

So basically Germany and the United Kingdom have done most of the job in a time when there was no economic crisis – and during economic crisis emissions usually go down. But the time we are talking about is fifteen years ago, a time when Germany has modernized itself. We have been very competitive and we are still now, although China is close to bypass us as leading exporting nation.

So this is not a lousy place but a booming economy and still Germany managed to reduce its CO2 emissions about a total of twenty percent compared to the level in 1990.

Q5) And how did they manage?

One part of the story is that the emissions of the German Democratic Republic were very high. After the break-down and modernization of its economy, emissions of this part of Germany decreased dramatically. The second part of the story has to do with renewable energy. Germany is a leading country in implementing photovoltaics and wind energy, although sun and wind conditions are much better in other countries.

The wind energy performance of the United Kingdom for example is absolutely poor, same if you look at Spain with solar energy. Why this? Germany’s institutional setting has created an incentive in 1992 by passing the "Erneuerbare Energie Gesetz" (German Renewable Energy Law).

The fundamental idea of the EEG is that grid operators must pay a government-specified feed-in tariff to energy generators supplying energy to the grid from renewable sources. This feed-in tariff is intended to make energy from renewable sources cost-competitive with that from traditional sources.

It is not an eternal sink of taxpayers' money but it an incentive system: you only get paid if you apply the newest technology and money is guaranteed only for a certain time period.

Then it decreases. Funny enough it has been the big political coalition of Christian-Democrats and Social-Democrats who launched this ambitious energy programme. This indicates that there has been a policy change linked to a value change since such a programme could not have been passed without public acceptance.

Q6) The Potsdam Institute for Climate Impact Research (PIC) is also involved in a project in the Indian mega city Hyderabad. From your experience, how can such mega cities reconcile population growth and urban problems with a climate-friendly policy?

Mega cities are truly important. For example, the carbon footprint of London is larger than that of Greece. But only Greece participates in international climate negotiations. If all the Londons on this planet acted against climate change, it would have a larger impact than maybe a Kyoto protocol including every country with only one percent reduction. Best example is the congestion charge which limited the entrance of cars to the inner city of London. It had been implemented despite much scepticism.

As a result London has reduced its CO2 emissions by twenty percent although this was only about congestion. But it is substantial.

In the case of India, the situation is more complicated: on the one hand, Indians emit only one ton CO2 per capita per year and live in great poverty but on the other hand, there is an emerging middle class with modern consumption habits. Together with other partners the PIC tries to improve the situation of the poor while reducing their carbon footprint by switching their cooking systems. So far they cook very inefficiently with wood and charcoal which is expensive and not sustainable.

Thus, there are local solutions that are very simple and even economically beneficial for the countryside. What we also need to do is to address the growing footprint of the middleclass. This is about car use and the poor performance of public transportation in Hyderabad – a typical phenomenon for cities that grow too rapidly. We are currently trying to talk with the Indian car manufacturer Tata who has produced the Nano, a very small Indian car. The Nano is the starting drug for cars since it is very cheap.

Until now it is a fossil-fuel based car and will raise emissions. But why not thinking about electro-mobility and renewable energy when producing this car? Besides, the middle class with its Western lifestyle are also well-educated and as environmental aspects are part of Western lifestyles they might integrate them partly as well. Also in the traditional Indian lifestyle there is a strong ascetic tradition. So there are cultural roots which can be utilized in order to raise awareness for climate change.

Q7) In Abu Dhabi in the United Arab Emirates, a model city called "Masdar" is currently constructed as first zero-emissions city, demonstrating that zero emissions and modern city life must not be contradictive. What could today’s mega cities learn from Masdar?

Masdar is a completely new built-up city. As urbanization goes on, cities are built even nowadays - not in Europe but in China and India. For them the blue-print of Masdar as a zero-emissions city is useful. It is good to have showcases like Masdar to demonstrate that it can be done and that we need political process, convincing local decision-makers to build new cities this way.

To the old stock of existing cities one can apply some but of course not all the principles of Masdar which are: zero CO2 emissions, zero waste and zero waste water. Let me give you some information about Masdar.

The city is 1.5 kilometres times 1.5 kilometres and planned for about 50.000 people around a university for renewable energy. The Abu Dhabi Future Energy Company has tried to generate all the needed energy on the spot. As the place is not large enough to generate all the energy for a conventional modern city, they had to think about city structure, spatial arrangement and adaptation to the harsh local natural conditions.

They came up with a city-type that looks like an ancient Arab city. The energy demands of all buildings are reduced. No elevators or escalators are provided. Besides there are no cars with combustion engines but only electric underground cars. Buildings are not higher than five stories and the appliances used inside are all low energy appliances with A++ standards. The inhabitants are given a sort of manual on how to use the city because we need climate-friendly technology but if the behaviour does not fit, it can still under-perform.

Q8) Considering all these trends and developments, what do you think can be achieved at the Kyoto-follow-up summit in Copenhagen in December 2009?

Well, that is difficult to assess. Three pictures are possible. One solution could be that we have a second version of the Kyoto protocol.

But in case the United Nations process comes to a deadlock it is thinkable that bilateral networks gain a new role. Under the Bush administration such bilateral talks with China and India started as counter initiative to circumvent the Kyoto protocol. So maybe if they come up with a treaty of only five countries for example the United States, India, China, Japan and Australia, this will be sufficient.

Or as a third rather grassroots-scenario, if nothing results from Copenhagen, then the role of civil society actors, business and cities will need to be reinforced.

Lena is a far travelled, critical individual and truly European citizen. Her main interest lies in the politics of the European Union, foreign affairs and globalization issues. During and after her BA in “European Studies” at the University of Maastricht (The Netherlands), she has worked both as a journalist and communications manager. Currently she works as a freelancer and is participating in the Erasmus Mundus Master programme.