Boulder should pursue an aggressive goal of reducing its greenhouse gas emissions 80 percent by 2050, and it can do that without extreme austerity if it can add a lot of renewable energy in the next decade through a municipal utility, City Council members said Tuesday night.

At a study session, the City Council took up the question of what the city's new climate goal should be, now that the Kyoto Protocol is widely viewed as inadequate to slow climate change: carbon neutrality or 80 percent reductions by 2050.

Many climate scientists believe at least 80 percent reductions are necessary to mitigate the worst effects of global warming.

Councilwoman Lisa Morzel supported the more ambitious goal of achieving complete carbon neutrality and pointed to the example of some European countries that have made significant strides in adding renewables and changing energy use.

City Council members did not take a vote Tuesday because they were in a study session, but a majority said they supported the 80 percent goal as more feasible and better defined.

Councilman Ken Wilson said to achieve complete carbon neutrality, the city would need to account for the goods residents buy, the food they eat, their airplane travel and every other product and service they use.

Without changing the energy supply, achieving an 80 percent drop in greenhouse gas emissions by 2050 would require Boulder residents to cut their electricity use a quarter by 2020 and in half by 2030. They would have to reduce their travel by car from an average of 20 miles a day in 2013 to less than four miles in 2050.

But Senior Environmental Planner Brett KenCairn said the future could be one of energy abundance and economic prosperity if Boulder adds significant renewable energy and positions itself as a leader in emerging technologies related to energy conservation and clean energy.

"This isn't just the right thing to do morally and ethically," he said. "It's actually the most powerful economic engine we could engage our community in to position ourselves for the future. The path to austerity is if we stay tied to carbon energy. The future is very bright with renewable energy."

For example, with cleaner electricity, people could drive electric cars without adding to the city's emissions.

Boulder Mayor Matt Appelbaum said more important than the city's stated goal is the rate at which it makes progress. With a municipal utility, the city could get half of its electricity from renewable sources within a few years.

But Councilman George Karakehian said the city may end up buying power from Xcel Energy for several years even if it forms its own utility.

Councilwoman Suzy Ageton said the city should be careful not to make commitments about things that are out of the city's control.

Environmental planners are working on five- and 10-year targets to keep the city on track to meet the new climate goal, which is expected to be formally adopted in early 2014, as well as new tools to help them measure their progress.

The city may eventually adopt new commercial energy-efficiency mandates, but planners say they first need better ways to track energy use in more complicated commercial buildings that may have multiple tenants or a wide variety of business types.

Boulder is also working with other cities, along the Front Range and in the Pacific Northwest, to share ideas and experiences working to reduce emissions.

One idea the city is considering -- borrowed from Portland -- is the idea of "eco districts," neighborhood organizations that would work on efforts to reduce emissions that matched local priorities, whether that was improving pedestrian safety so people can walk more or contracting collectively for solar panels.

The effort will be tied into other city initiatives, from the transportation master plan to neighborhood design to building codes.