United Nations’ Department of Economic and Social Affairs in its new report "The World Economic and Social Survey 2011: The Great Green Technological Transformation" stated that we need $1.9 trillion per year over the next 40 years for incremental investments in green technologies to “avert the likely catastrophic impacts of climate change and environmental degradation.”
UN recommends we should focus on “four key goals: improving energy efficiency without expanding consumption where energy-use levels are high; supporting a broad global energy technology development portfolio while scaling up the use of known green technologies in specific places; supporting greater experimentation and longer discovery times; and applying superior governance and accountability strategies in energy-related technological development than at present.”