According to a UN report, that's how much it will cost per year to transform human societies in order to prevent ecological catastrophe. From Fast Company:
Companies and governments the world over are investing billions of dollars in transitioning to clean energy, more efficient agricultural production methods, and climate-proof city infrastructures--but is it enough? We will have to invest $1.9 trillion each year for the next 40 years in these new technologies, or face a major planetary catastrophe. About $1.1 trillion of those investments will have to go to developing countries.
According to the U.N.'s annual economic and social survey, we need to radically overhaul our production and consumption processes or potentially destabilize the planet's ecosystem. This means reducing resource and energy requirements in our daily lives, moving towards renewable and biodegradable resources, cutting down on waste, and protecting biodiversity and ecosystems.
What are the chances of this happening? Given the World Bank has distributed only $20 billion over the past two years for climate change funds, it doesn't look good. But as the UN report concludes, things might start getting so dire, we may not have a choice.