Politicians will put the world economy at risk if they fail to tackle climate change, a global commission has warned.
The body, a group of chief executives, former prime ministers and finance ministers, argues the cost of tackling climate change is modest.
Its report says adding 5% to the $6 trillion (£3.7tn; 4.6tn euros) a year due to be spent on power and transport projects could buy clean technology.
Critics say the report is too optimistic.
The Global Commission on the Economy and Climate was set up by seven governments and informed by research organisations around the world.
It is chaired by former Mexican President Felipe Calderon and advised by Lord Stern, former UK government economist and author of a previous review of climate change economics.
Its report says one key to safeguarding the climate is to change spending priorities for new infrastructure.
Creating sprawling car-dependent cities will lock in high pollution, whilst planning dense cities with good public transport will help keep emissions down, cut local pollution and improve quality of life, it says.
The commission says that by developing in this way, governments can collectively save $3 trillion over the next 15 years.