> So how much economic damage will pursuing the IPCC's fast transition to a no-carbon energy system spare us? The report asserts that if no policies aimed specifically at reducing carbon dioxide emissions are adopted, then average global temperature is projected to rise by 3.66°C by 2100, resulting in global GDP loss of 2.6 percent from what it would otherwise have been. Comparatively speaking, in the 2°C and 1.5°C scenarios, global GDP would only be reduced by 0.5 percent or 0.3 percent respectively.

> Concretely, the global GDP of $80 trillion, growing at 3 percent annually, would rise to $903 trillion by 2100. A 2.6 percent reduction means that it would only be $880 trillion by 2100. A 0.3 percent decrease implies a loss of $2.7 trillion resulting in a global GDP of $900 trillion. Note that the IPCC is recommending that the world spend between now and 2035 more than $45 trillion in order to endow $2.7 trillion more in annual income on people living three generations hence. Assuming the worst case loss of 2.6 percent of GDP in world with a population of 10 billion that would mean that they would have to scrape by on an average income of just $88,000 per year (the average global GDP per capita now is $10,500.)