Chicago has announced a climate change action plan designed to reduce the city's carbon emissions to three quarters of 1990 levels by 2020.

The goal, which goes well beyond the requirements of the Kyoto protocol, has been praised as aggressive by environmental commentators.

The plan, which is part of a longer-term goal to cut carbon emissions to 80 per cent below 1990 levels by 2050, consists of 35 separate actions spanning five broad categories: building efficiency, clean and renewable energy, transportation, pollution and adaptation.

Goals set by the city for building efficiency include retrofitting industrial, commercial and residential buildings for energy efficiency, and the creation of 6,000 rooftop gardens – up from just 400 today.

The city energy code will also be updated, and the plan aims to reduce enough appliance and lightbulb energy consumption through equipment trade-ins to eliminate 28 million metric tonnes (MMT) of CO2.

In addition, the strategy calls for upgrades of Illinois' 21 coal-burning power plants – including two in Chicago that would save 2.5MMT through efficiency improvements – and will encourage small-scale, distributed power systems based on renewable energy, including household-based microgeneration technologies such as solar panels and wind turbines.

It will also seek to cut down transport-related emissions by increasing investment in the transit system, and encouraging greater residential developments around transit stops. Moreover, cycling, car sharing and a shift to fuel-efficient and hybrid buses will be promoted alongside plans for a high-speed intercity rail link and more energy-efficient freight movement via barge and rail.

The pollution reduction element of the plan calls for a 90 per cent reduction in waste shipped to landfill, and will phase out hydroflourocarbons found in refridgerators, while also capturing storm water onsite.

Finally, the adaptation section of the plan will prepare the city for the effects of global warming through improved heat management and the extension of an existing "green urban design" initiative between city departments that aims to implement water management and heat dissipiation technologies.

Chicago officials failed to give a clear price for the initiative, but observers said the proposals would raise the bar for other urban centres.

"It is one of the most aggressive moves that I have seen from a city," said Annie Strickler, spokeswoman for the US arm of ICLEI-Local Governments for Sustainability, an international association of local governments pursuing sustainable development.

Strickler highlighted San Francisco and New York City as the two other leaders in environmentally friendly local government, but added that they had now been joined by Chicago.

In related news, New York has just installed the first of up to 300 aluminium alloy-based turbines in its East River, which officials claim could generate power for up to 10,000 homes.