The new targets include net zero emissions on or before 2045, with interim targets of 50 to 60 per cent emissions reduction by 2025; 65 to 75 per cent by 2030; and 90 to 95 per cent by 2040, all compared to the ACT's emissions in 1990. The 2020 target, which has been in place for several years, is a 40 per cent reduction.

Meeting an emissions trajectory like this would mean the ACT does its fair share to cut greenhouse-gas emissions in line with the Paris agreement of holding global warming below 2 degrees. The ACT would help lead the way in Australia by respecting the boundaries set by its "carbon budget", and demonstrating how to make deep reductions in an urban economy.

The idea behind setting a clear trajectory to zero emissions is that business, government and the ACT community can invest in modern, low-emissions technology with confidence about the overall goal, knowing that policy will support the shift. Climate action is part of creating a healthier, better-connected, more resilient and prosperous city. Positive change can occur in nearly every aspect of life in Canberra.

As one of Australia's richest communities, we should find it easier than elsewhere to invest in the necessary change. And taking a lead in climate-friendly modernisation helps attract highly skilled people to Canberra, which is what is needed for continued economic success in the ACT. Canberra has a national, and growing international, reputation for innovation in the low-carbon economy, and ACT energy and climate policy programs have already attracted global renewable-energy companies.

The targeted reductions are steep, but they can be achieved if government, businesses and the community all make a sustained effort.

The ACT is on track to have 100 per cent of its electricity sourced from renewables by about 2020. This will make possible the targeted 40 per cent reduction in emissions (as they are accounted in the ACT). Carbon-free power supply gives us emission-free options for other sectors, notably transport – electric cars and buses, as well as light rail – and the use of electricity instead of gas for heating, cooking and in industry. This is critical because transport and natural gas use account for the lion's share of Canberra's direct emissions outside of electricity generation, at about 65 per cent and 20 per cent respectively.

The vision is clear: a transport system where public transport, as well as biking and walking, play a bigger role; where almost all cars, buses and trucks run on electricity or hydrogen; and where almost no gas is used. Quite aside from climate change, this means even cleaner air in Canberra and much less noise. The shift to higher-density living and the rapid progress with electric cars will help make it possible. Electric bicycles are already an alternative.

The first step is to stop investment that locks in carbon use into the future. We need electric cars and buses rather than petrol and diesel, and electric heating systems, not gas. Extra investment to improve energy efficiency in houses, apartments and public buildings is needed, too.

In all of this, the ACT government can and should lead by example. And climate policy must go hand-in-hand with social policy, ensuring that the shift to a truly clean city does not put some groups at a disadvantage. That means a keen eye on energy costs and the needs of commuters in the suburbs, and increased engagement by all of us during the transition.

Penny Sackett, an honorary professor at the ANU, is a former Australian chief scientist; Frank Jotzo is a professor at the ANU's Crawford school of public policy; and Will Steffen, an emeritus professor at the ANU, is on the Climate Council of Australia. The authors are on the ACT Climate Change Council, an independent statutory body that advises the ACT government on climate change and paths for action. This is the first of several articles exploring how Canberra can transition to carbon neutrality.