In his recent Science article The Irreversible Momentum of Clean Energy, President Obama jumped into the "growth vs. levels" debate among empirical economists studying the effects of climate change, writing
[E]vidence is mounting that any economic strategy that ignores carbon pollution will impose tremendous costs to the global economy and will result in fewer jobs and less economic growth over the long term. Estimates of the economic damages from warming of 4°C over preindustrial levels range from 1% to 5% of global GDP each year by 2100 ... In addition, these estimates factor in economic damages but do not address the critical question of whether the underlying rate of economic growth (rather than just the level of GDP) is affected by climate change, so these studies could substantially understate the potential damage of climate change on the global macroeconomy (8, 9).
and citing the recent GPL paper on the global effects of temperature on growth.
Talk about a president who gets into the nuts and bolts...