Put together by research teams from 15 countries that represent 70 percent of total greenhouse gas emissions, the report lays out a long-term global strategy to keep temperatures from rising by 2 degrees Celsius (3.6 degrees Fahrenheit) above pre-industrial levels.

If enacted, the series of measures described in the report would see cuts of 45 percent in emissions related to energy by 2050 from 2010 levels, or just short of what is needed to keep temperatures from rising more than 2 degrees.

The projected cuts are ambitious and the authors acknowledge that many of the hurdles that have stymied efforts to combat global warming until now could also derail these proposals — namely, political opposition as well as the feasibility of deploying technological solutions that are currently too costly or not yet proven on a commercial scale.

“The world has committed to limiting warming to below 2 degrees, but it has not committed to the practical ways to achieve that goal,” said Jeffrey Sachs, director of Columbia University’s Earth Institute and the Sustainable Development Solutions Network, which published the report.

The report proposes pathways that are unique to each country depending on its circumstances. China, for example, would depend on nuclear for a quarter of its electricity by 2050 and is part of an effort to build momentum to climate talks next year in Paris when countries are expected to ink a global deal limiting emissions starting in 2020.

Laurence Tubiana, the French ambassador for climate negotiations, said the report allows countries to think about the issues longer term rather than debating short-term fixes, such as immediate cuts, which often devolved in the past into finger pointing between rich and poor nations over who should take the lead.

“We know countries will not be able to set up targets or contribution or plans that can make up for the 2 degrees. The step is too high,” Tubiana said of the 2015 talks. “That is why this type of exercise is important. What if we project our future into 2050 and see how to get there? Many times, people are stuck in short-term vision. Of course, changes are not possible in the short-term. You cannot switch your energy system in 20 years time. You need at least 40 or 50 years.”

Tubiana also said she felt countries were more willing than during the 2009 climate talks in Copenhagen to consider some of the hard choices necessary to shift to a low-carbon economies. A big part of that, she said, was that the impacts of climate change — droughts in the United States, or floods and heat waves in Europe — are becoming harder to ignore.

Under the report’s plan, the United States would continue to expand its economy, but gradually shift away from traditional fossil fuels — such as oil, coal and gas — and toward renewables. Electricity, for example, would be generated by a mix of 40 percent renewables, 30 percent nuclear and 30 percent fossil fuels that use carbon capture and sequestration technology to capture and bury the carbon dioxide — a solution that until now has struggled to overcome safety and other concerns.

“There is no magic bullet to this when you are talking about electrification of vehicles, when you are talking about changing land use, when you need a new grid system, when countries need to make decision about nuclear energy, when countries need to do the research and development around carbon capture and sequestration” Sachs said, adding that countries need to significantly ramp up its research and development into green technology to enable the switch.

“What we need to do is to understand that all countries need to make a very deep transformation and that some of the technologies that we need for that still need to be improved markedly or proved at large scale in order to be implemented,“ he said.