The global environmental cost of human activity is around $6.6 trillion a year or 11 per cent of the global economy. This is an estimate from the UN Environmental Program in a report first published in 2011. The report also says:
“...companies in the MSCI All Country Index are associated with over S$1 trillion in environmental externality costs annually, This equates with 5.6 percent of the market capitalization of companies in the index and 56 per cent of their earnings”
Not sure why the UN uses MSCI All Country Index as the benchmark - I'm guessing because it apportions blame to everyone. But it gives a sense of how much would change if companies had to pay for their environmental costs.
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