Resumo :Este artigo aborda aspectos legais do conceito da sustentabilidade e a forma como é tratado na legislação e política alemã. Discute-se, ainda, até que ponto o conceito faz parte da Constituição alemã e se é recomendável uma emenda a este respeito.
The concept of sustainable development was codified in the Declaration of Rio de Janeiro as a consequence of the United Nations Conference on Environment and Development in June 1992, and it has been substantiated, for example in the Agenda 21, the United Nations Framework Convention on Climate Change UNFCCC, the Kyoto Protocol, and the Johannesburg Plan of Implementation. Today, in common understanding on the international level, the concept does not only approach the preservation of the availability of the Earth’s nature resources for subsequent generations at any cost, but beside this ecological aspect, it also includes two other aspects: the economic and the social. Together, the three aspects represent what is referred to as the "triple bottom line". That means that according to the concept, any strategies of preserving the Earth in favour of future generations have to sufficiently take into account the presently living people and their present needs as well. Therefore, a sustainable development comprehends the task of harmonizing and conciliating these three components, which in general are interdependent, which can be contrary, and none of which is supposed to have absolute priority in the first place over the others.
Sustainable development was set as a substantiated objective on the international level. The Rio Declaration, as the principal document, proclaims 27 principles to be pursued in order to achieve sustainability.  However, the implementation of the objective at a lower level, that means: in the particular polities, is a necessary requirement,  down to the local level.  It is needless to say at this point that, due to the obvious depletion of resources and climate change, the imperative for action is undiminished.
This article shall contemplate legal aspects to this issue; in fact, it shall be done here from one national point of view: In Germany, like in many States all over the world, efforts have been made to develop strategies for sustainability. In large part, these strategies are now reflected in statutory legislation where the term of „sustainability" has gradually become more widespread over the past decades, and therefore nowadays jurists have to deal with it and its interpretation more than ever.
After clarifying the contents and meaning of the concept of sustainability in German statutory legislation (below in part II) and pointing out the recent German governmental strategies and their legal reflection (part III), this article shall focus on constitutional law. Although the concept of sustainability does not appear explicitly in the Basic Law, which is the German Constitution,  it is to be examined how and to what extent the current Constitution contains the essence of sustainability in its provisions. Particularly section 20a of the Basic Law that makes arrangements about the environment shall be of great interest in this context (part IV), as is the debate about a possible constitutional reform in regard to sustainability beyond the existing section 20a (part V).
II. The interpretation of "sustainability" in German statutory legislation
The term "sustainability" was not invented in 1992 on the Rio Conference, but it has had a history on the national level, in Germany too. It must be noted that there cannot be given one single definition for the term "sustainability" (or the adjective "sustainable")  that would be generally applicable for the entire German legislation. It still has rather different meanings in different legal contexts. 
One reason for this finding is that the term has been used in legislation for a long time, having had to fulfill certain purposes in certain fields of law. In some contexts, there is no necessary relation to the objective of preserving the environment and it simply stands for the meaning "long-lasting, considerable". For example, in criminal law, it is used in a negative sense, to qualify offences, describing the damage that was caused to protected values or objects. Only when a damaging behaviour is nachhaltig, it is then considered worth being punished. Such an understanding shall be of no interest for this article.
In other contexts, the term relates to the preservation of resources. There, it targets at the avoidance of the complete consumption of a resource, in order that subsequent generations may be able to enjoy the resource as well as the present generations. Consequently, forestry acts, for example, have been regulating the amount of wood extraction in a certain period of time so that the forest would always be able to recover and could subsist as a permanent resource for the people.
Another reason for the non-uniform interpretation is the gradual overlap by international law. In the course of time, international documents and treaties have been negotiated, and during this process, an international understanding of the concept of sustainability has shaped. The international understanding is wider, as mentioned above, for it takes into account not only the ecological, but also an economic and a social component. So in many cases, there is a deviation from the traditional – narrower – understanding in German law that had ascribed to the term, if any, only an ecology-related content. Meanwhile, in the most recent legislation where the term appears, it is obviously meant to be interpreted in the "enriched", internationally influenced way, according to the "triple bottom line" including social welfare and economic concerns (for example in the federal and state Nature Preserve Acts and in Spatial Planning Acts). Therefore, it is ascertained that in these laws, the approach is not only intergenerational, but also intragenerational.
To sum up, the interpretation always depends on the spirit and purpose and also on the date of enactment of a specific law.
III. Recent goals and measures in German sustainability politics
These modern statutes concerning sustainable development are the product of the pursuit of sustainability strategies that have come to the politicians’ field of vision more and more intensely. It has been part and parcel of the recent coalition agreements. Recently, on 27th November 2007, on the occasion of consultations for sustainability strategies, the head of German Government, Federal Chancellor Angela Merkel, is quoted making a commitment to "sustainability as a leading principle in German politics", emphasizing that it is not enough to settle for what has already been accomplished. She continued that, to live well, "we do not necessarily need to consume ever more resources and ever more energy", and that for the development of sustainability strategies, everyone is called upon to contribute because it is not a matter to be imposed and accomplished unilaterally by the Government. 
Sustainability strategies and policies work in different fields, which demonstrates how the achievement of a sustainable development, in general, is a cross-sectional matter. For this reason, high-ranking secretaries of different ministeries meet regularly in a committee to exchange ideas that could not be implemented in only one ministery by itself.  In 2009, the Federal Ministries’ Joint Rules of Procedure  were officially amended to make sure that the long-term effects for sustainable development of any legislative bill are contemplated and exposed in the motivation within the process of law-making. 
In the following paragraphs the actual and concrete strategies, which have been announced and executed by the Government to obtain and maintain a balance between ecological, social and economic needs, shall be summarized.
To begin with, in April 2001,  as an organizational measure, a special Sustainability Council  was established on the initiative of the former Government’s Federal Chancellor Gerhard Schröder,  and summoned again by his successor Angela Merkel. The Council is pluralistically composed of 15 figures who are renowned in various sectors of public life (members have been the former director of the UNEP, a church representative, a former minister, scientists, presidents of nature conservation organizations, a trade unionist, and other important decision-makers). Its duty is the conception of contributions with regard to the implementation of the national sustainability strategy, especially evaluating and commenting its objectives and measures, and permanently advising the Government. Likewise, the Council is entrusted with the task to specify concrete fields of activity and with the realization of projects  as well as, in general, with keeping the concern for sustainable development in the public attention. Inter alia, the Sustainability Council has issued recommendations for the increase of the responsibility of commercial enterprises (corporate social responsibility – CSR)  as one further important approach to be pursued, especially against the background of the necessity to involve society in the quest for sustainable development. 
It has to be made perfectly clear at this point that the Council’s appointment is not provided for in the Constitution. It is a product of Government’s general policy-making power which was assigned in section 65 of the Basic Law, where discretion (within the framework of the Constitution) is left to the Government about the ways of reaching their legitimate political objectives.
One year later, in April 2002, German Federal Government issued the Sustainability Strategy Paper entitled „Perspektiven für Deutschland".  It contains ten so-called Management Rules and, most importantly, an overall outline of the areas of politics where measures would have to be taken to create sustainability and to fill the concept with life, as it had been the intention of the Rio de Janeiro Conference in 1992. Furthermore, the Strategy Paper, that is still valid in 2009, contains the dedication to the continuous monitoring of the abidance that is to be documented until today in biennial Progress Reports.  It also contains the dedication to reevaluating the measures on a regular basis. As a matter of fact, the Sustainability Council has influenced the further development of strategies considerably by critically responding to the Government’s reports. In August 2005, another remarkable document, "Guidepost to Sustainability", that was conceived by the permanent secretaries’ committee (Green Cabinet) was passed by the Federal Cabinet to fill the strategy with more details and the experiences that were made in the meantime. 
The Government strategy is less a strategy made of single projects than a systematic one,  that means: principles and goals are envisaged, then measures are determined, then it is reviewed by means of indicators whether these measures have been successful.
The basic thought in these Management Rules is that every generation has to solve their own problems and to refrain from leaving burdens to future generations. When solving those "own problems", the preservation of the environment and the social and economic needs of the today’s people are to be envisaged likewise. For they outline well the scope of the governmental strategy, the Management Rules are quoted here directly: 
1. Citizens, producers and consumers, economy and trades unions, science, churches and other associations are, with the State, important participants in Sustainable Development. They should participate in public dialogue concerning the model of a programme of Sustainable Development and on their own initiative direct their decisions and initiatives toward these goals.
2. Businesses are responsible for their means of production and the goods they produce. This responsibility includes informing consumers of features of their products relevant to health and the environment, and also of sustainable means of production. The consumer is responsible for choosing the product and for using it in ways which are socially and environmentally acceptable.
3. Renewable natural commodities (such as, for example, timber or fish stocks) will in the long term only be used within a framework which takes account of their regenerability. Non-renewable natural commodities (such as, for example, minerals or fossil fuels) will in the long term only be used within a framework where consideration is given to how their functions can be replaced by other materials or by other forms of fuel. The release of substances or energy will in the long term be no greater than the level which can be sustained by the ecosystems – e.g. the climate, the forests and the oceans.
4. Dangers and unjustifiable risks to human health are to be avoided.
5. The structural changes triggered by technological developments and international competition are to be managed in a way which is both economically successful and ecologically and socially acceptable. To this end, the various areas of policy are to be integrated in such a way as to ensure that economic growth, high employment, social cohesion and protection of the environment go hand in hand.
6. Use of energy and resources and also transport must be decoupled from economic growth. At the same time efforts must be made to ensure that rises in demand for energy, resources and transport resulting from growth are more than compensated for by increased efficiency.
7. Public-sector budgets are also bound to take account of fairness to different generations. The State, the Länder  and local authorities are to draw up balanced budgets as soon as possible and, as a further step, continually reduce their levels of debt.
8. A sustainable form of agriculture must be compatible with nature and the environment and must have regard to forms of husbandry which respect the rights of animals, and to preventive forms of consumer protection, especially as regards health.
9. To strengthen social cohesion, preventive measures should as far as possible be taken to combat poverty and social exclusion, the whole of the population should be offered opportunities to take part in economic development, everyone should participate in social and political life.
10. The international framework conditions are to be devised in such a way that people in all countries can lead a life of human dignity according to their own cultural principles and can participate in economic developments. Environment and development form a unity. In an integrated approach the fight against poverty is to be linked to respect for human rights, to economic development, environmental protection, and also to responsible action on the part of Government.
There is a basket of approaches to be found in the Strategy Paper (and pursued in the Progress Reports and "Guidepost") which are to animate these written Management Rules.
First of all, as to the crucial issue of energy demand,  there is a dual strategy: On the one hand, there is the need to increase energy efficiency. It shall be accomplished by an enhanced effectiveness of power plants, combined heat and power generation, the development of fuel cells,  incentives for the production of cars with lower gas mileage, a categorization of household appliances in terms of energy efficiency and rules for appropriately labelling them, and the subsidization of the refurbishment of buildings . On the other hand, the use of renewable energies shall be extended, especially wind and solar power, with the objective for them to represent half of the energy supply until the year 2050, accompanied by slowly phasing out of nuclear energy.
To realize this practically, there has been a need for shiftings in the budget, allocating funds for technologies that are worthy of supporting, allocating funds for subsidization. Modifications in tax law should also be mentioned, for example the rise in petroleum tax to privilege frugal vehicles. One of the main legislative measures in regard to energy politics has been the Renewable Energy Sources Act 2004 which is already serving as a role model for legislation in numerous other countries. As regards content, the act provides for financial reimbursement rates to operators of all kinds of renewable energy power plants, effected per kilowatt-hour that is inducted into the grid. It went along with the new Atomic Energy Act 2002, which is a result of a major rethinking in politics. The act emanated from the so-called „nuclear energy consensus" („Atomkonsens"). It came into force in April 2002 featuring a new legal intention which set a striking new course for the future: The purpose of the law was not anymore the secure handling, but the controlled finalization of the use of nuclear energy because of the long-term risks and the persistence of the residual wastes that affect many generations. In this spirit, the act prohibits the construction of new nuclear power plants, it limits the general running periods of existent power plants, and caps their permitted gigawatt-hour outputs. Furthermore, the act features the requirement of regular safety inspections, the prohibition of the recycling of nuclear wastes (instead pronouncing the preference of ultimate disposal), and the raise of the compulsory financial security by plant operators (tenfold, up to 2,5 billion € each and an unlimited personal liability). This consensus is law of the land, but it is also true that it has been put into question and criticized, mainly because of the consequence that, without nuclear energy, more fossil fuels would have to be burnt to meet the energy demand, and there would be a dependence on other countries’ resources. On grounds of this, actually, the conservative-liberal coalition elected in 2009 is heading for a renunciation of the "nuclear energy consensus".
Secondly, there are strategies in the Paper that concern the area of mobility:  As to the transport of goods there shall be an intensification of railway traffic rather than road traffic to decrease the amount of heavy goods vehicles. This way, there shall be a reduction of noise, exhaust gas pollutions, and the impairment of landscape by usage for road-construction.
The means to achieve this has been a highway toll for heavy goods vehicles. An upgrading and modernization of the railway infrastructure and the improvement of the railway system efficiency are also scheduled,  with the objective being 25% of the total capacity of transport of goods to be carried out by rail until 2015. Besides, to reduce transport on the whole, more effort shall be put on the regional marketing of agricultural products.
Thirdly, there are strategies regarding the promotion of healthy food and alimentation.  Consumers shall be enabled to make informed decisions on the market based on sufficient (not unclear, misleading) information about the products. It premises a system of labelling with meaningful certificates of quality and origin, informing about ecologically compatible production and processing, so that the market can fairly determine which products shall prevail in the competition. Such a steering effect of the hence transparent market shall go along with subsidies for agriculture under specified conditions. Further goal is the preservation of culturally developped landscapes and a high esteem for animals in husbandry and transport, the latter was implemented in the Animal Protection Act 2006.
The fourth issue that was addressed in the Strategy Paper is demographic change.  This has been of a particular concern in this country since less children have been born and society’s average age soars rapidly and threatens to continue to do so.  This aspect belongs to the social component of sustainable development, bearing in mind that any development requires an (at least) stable population for many reasons that cannot be treated in detail in this article. Anyway, the measure considered to halt the decrease of population is that families and children (with or without the parents being married) shall be promoted, keeping in mind justice between the generations. This promotion is accomplished through child allowances, tax reliefs and exemptions, a system of all-day child care, more student and vocational loans and grants, and the facilitation of parental leave.
As to education,  the objective is to reduce the quota of people without university entrance qualification or vocational degree; likewise the increase of the quota of university graduates. There shall be an early promotion particularly for children from socially disadvantaged and immigrant families, even in pre-school age, to cut back inequality due to the social and geographic background, and a collaboration between school and parents’ house.
The next issue concerns innovations in the economy.  It shall be accomplished by a cutback of too detailed, meticulous regularizations where they are not necessary, hence creating wider scopes for decision-makers and more room for innovative ideas. Besides, there is the vision of more interdisciplinary research teams and an enhanced networking between science and economy.
In spatial and settlement planning,  the central goal is the preservation of areas to be left clear. Now, the Federal Nature Protection Law sets up the objective of creating a network of biotopes to constitute at least 10% of the country’s total territory, cf. section 3. The consideration of nature preservation and landscape conservation are to be taken into account on every occasion where legal values and interests have to be balanced and appreciated by authorities in urban and regional development and planning law in order to achieve an optimal use of space within municipalities and on higher levels.
Finally, one part of the national strategy involves the awareness of global responsibility  which demonstrates again the interlinkage between the different levels of action. For the global level, there is the idea to found a United Nations World Commission for Sustainability and Globalization with a new conception of competences, to be made up of internationally renowned figures on the model of the Brundtland Commission.  The main objective was identified as the fight against worldwide poverty and the reduction of inequality, for example by means of debt write-off programmes,  the promotion of basic education in cooperation with developping countries, the budgetary allocation of a specified minimum percentage of the gross national product for the public development assistance, the strengthening of the United Nations Environment Programme (UNEP), and – what is important to a high degree – the opening of the markets by cutting back import tariffs and export subsidies.
A great deal of this tariff and subsidy policy is done within the framework of the European Union (EU). Policies concerning sustainable development cannot be described without – at least briefly – mentioning the ongoing cooperation within the EU, for member states, such as Germany, are engaging on this level as well. The Preamble of the Agenda 21 expressly ascertains that when the term "Governments" is used in this document, it will be deemed to include the European Economic Community (as an integral part of today’s EU structure) within its areas of competence. The principle of sustainability is laid down in the statutes of EU, see section 2 of the Treaty on European Union and 6 of the Treaty on European Community as well as both treaties’ preambles. The importance is due to the fact that the application of European law takes priority over national law.
The EU itself  put forward a "European Sustainability Strategy" in 2006,  expressing the commitment to strengthen the dialogue with partners beyond the EU, and containing seven central challenges to accept. It aligns with the German national policy aiming largely at similar approaches. The above-mentioned national Sustainability Council takes part in the European network of similar councils throughout the continent who play a role in monitoring jointly the European strategy. To accentuate one important point on the European level: Greenhouse gas emissions are determined to be reduced until 2020 by 20% compared to 1990 (which equals 14% compared to 2005) and 20% of the power generation shall be attained from renewable energies. This leads to another quite recent innovation: the trading of emissions with certificates listed on the stock exchange. This way, enterprises can buy pollution rights, the total amount of emissions is controlled and heavily polluting industries have to pay proportionally.  Initially the certificates are auctioned with the revenues being used for the promotion of climate-related innovations. Still, there are fixed exceptions concerning certain industry branches for fear of their moving abroad (for example steel and aluminum).
After all, an evaluation is necessary to recognize to what extent measures like these have been successful and reached specific benchmarks. That way, it can be determined whether to continue or reconsider them. The evaluation is to be effected by means of 21 performance indicators seeking to make the progress quantifiable, much as it is difficult to measure sustainability. The indicators were also set up by the Government in the 2002 Strategy Paper and need to be reproduced here: 
1. Productivity of energy and raw materials
2. Emissions of the six greenhouse gases specified in the Kyoto Agreement
3. The proportion of renewable energy sources in overall energy consumption
4. Increase in land use for housing and transport
5. Development of the stocks of specified animal species
6. Balance of public sector financing
7. Capital-outlay ratio
8. Private- and public-sector expenditure on research and development
9. Educational outcomes for 25-year-olds and number of new students
10. Gross domestic product
11. Transport intensity and share of the railways in providing goods transport
12. Proportion of ecological agriculture and general statement on nitrogen surplus
13. Air pollution
14. Satisfaction with health
15. Number of burglaries
16. Labour force participation rate
17. Full-time care facilities
18. Relationship between male and female gross annual earnings
19. Number of foreign school-leavers who have not completed secondary school
20. Expenditure on development collaboration
21. EU imports from developing countries
By dealing with such fixed values, the monitoring of the chosen policies becomes transparent and traceable. In 2006, an "Indicators Report" was published by the Federal Statistical Office on behalf of the Government, demonstrating the success that had been made as well as still existent deficiencies.  In 2008, a revised version was publishes.
The latest institutional action that was taken on the political stage and that shall be noted here is the formation of a special Parliamentary Advisory Committee for Sustainable Development in the Bundestag.  Just like the Sustainability Council it is not provided for in the Basic Law. It is a consortium of delegates, an interest group consisting of 40 members with similar concerns. It was constituted in June 2006 and its aim is to "advocate for long-term responsibility in favour of the future generations" in political events and legal projects, since the Committee is part of a law-making body. The delegate’s intention is to discuss objectives and instruments collaterally with other organs of State, to give recommendations as to medium- and long-term strategies, to make consultations with other parliaments (within the federal Republic and particularly within the EU), and at last, report biennially about its work.
The initial Strategy Paper of 2002 was combined already with a request towards all groups of society for involvement within the bounds of possibility. The permanent discussion and collaboration between as many participants as possible in society was declared to be a key element in the Paper.  "Interested citizens" are regularly asked for contributions and suggestions concerning the further development of sustainability strategies for the next progress report.