Developing and emerging economies, with the exception of China, will need investments well in excess of $2 trillion a year by 2030 if the world is to stem the destructive force of global warming and deal with its consequences, a UN report noted.
A trillion dollars must come from wealthy countries, investors and multilateral development banks, according to the analysis commissioned by Britain and Egypt, which are hosting respectively the 2021 UN climate summit in Glasgow and this week's COP27 event in Sharm el-Sheikh.
The rest of the money - about $1.4 trillion - must come from private and public sources.
Current investment in emerging and developing countries other than China is about $500 billion.
The new 100-page analysis, Financing for Climate Action, is presented as an investment plan for "greening" the global economy to meet the Paris Climate Agreement's goals of limiting global temperature rise above two degrees Celsius and, if possible, to 1.5 degrees Celsius. Warming above this threshold, scientists warn, could push the Earth into an uninhabitable greenhouse state.