The most interesting from an incomplete 2007 survey.
llinois

Article XI (1970): “The public policy of the State and the duty of each person is to provide and maintain a healthful environment for the benefit of this and future generations. The General Assembly shall provide by law for the implementation and enforcement of this public policy.  Each person has the right to a healthful environment. Each person may enforce this right against any party, governmental or private, through appropriate legal proceedings subject to reasonable limitation and regulation as the General Assembly may provide by law.”
 

Hawaii

Article XI: “For the benefit of present and future generations, the State and its political subdivisions shall conserve and protect Hawaii’s natural beauty and all natural resources, including land, water, air, mineralsand energy sources, and shall promote the development and utilization of these resources in a manner consistent with their conservation and in furtherance of the self-sufficiency f the State. All public natural resources are held in trust by the State for the benefit of the people”  

Namibia

Article 100: “Land, water and natural resources below and above the surface of the land and in the continental shelf and within the territorial waters and the exclusive economic zone of Namibia shall belong to the State if they are not otherwise lawfully owned.”.

Article 95 (l) “The State shall actively promote and maintain the welfare of the people by adopting, inter alia, policies aimed at the … maintenance of ecosystems, essential ecological processes and biological diversity of Namibia and utilisation of living natural resources on a sustainable basis for the benefit of all Namibians, both present and future; in particular, the Government shall provide measures against the dumping or recycling of foreign nuclear and toxic waste on Namibian territory.”

The Constitution also charges the Ombudsman to investigate the destruction of ecosystems and the over-utilization of natural resources, thus ensuring environmental accountability.

Lesotho

(1993) Section 36: "Lesotho shall adopt policies designed to protect and enhance the natural and cultural environment of Lesotho for the benefit of present and future generations and shall endeavor to assure all citizens a sound and safe environment adequate for their health and well-being.

Eritrea (1999) Article 8.2 provides: "The State shall work to bring about a balanced and sustainable development throughout the country, and shall use all available means to enable all citizens to improve their livelihood in a sustainable manner, through their participation".

Article 8.3: "In the interest of present and future generations, the State shall be responsible for managing all land, water, air and natural resources and for ensuring their management in a balanced and sustainable manner; and for creating the right conditions to secure the participation of the people in safeguarding the environment".

Burkina Faso

Article 29: "The right to a healthy environment is recognized; it is the duty of all persons to protect, safeguard and enhance the environment".

Republic of Uganda (1995)

"The State shall promote sustainable development and public awareness of the need to manage land, air, water resources in a balanced and sustainable manner for the present and future generations"

"The utilization of the natural resources of Uganda shall be managed in such a way as to meet the development and environmental needs of present and future generations of Ugandans; and in particular, the State shall take all possible measures to prevent or minimize damage and destruction to land, air and water resources resulting from pollution or other causes".

South Africa

(c.1996)  24 Everyone has the right –

(a) to an environment that is not harmful to their health or well being and

(b) to have the environment protected for the benefit of present and future generations through reasonable legislative and other measures that –

(i) prevent pollution and ecological degradation,

(ii) promote conservation; and

(iii) secure ecologically sustainable development and use of natural resources while promoting justifiable economic and social development.  

Norway

Article 110 b
Every person has a right to an environment that is conducive to health and to natural surroundings whose productivity and diversity are preserved. Natural resources should be made use of on the basis of comprehensive long-term considerations whereby this right will be safeguarded for future generations as well. In order to safeguard their right in accordance with the foregoing paragraph, citizens are entitled to be informed of the state of the natural environment and of the effects of any encroachments on nature that are planned or commenced.

Pennsylvania Constitution.

(1971) Article I, Section 27: “The people have a right to clean air, pure water, and to the preservation of the natural, scenic, historic and esthetic values of the environment. Pennsylvania’s public natural resources are the common property of all the people, including generations yet to come. As trustee of these resources, the Commonwealth shall conserve and maintain them for the benefit of all the people.”

Montana’s 1972 constitution

“The state and each person shall maintain and improve a clean and healthful environment in Montana for present and future generations.”

Swiss Confederation

Article 2 of the Federal Constitution declares sustainable development to be a national objective