Most important, a one hundred percent renewables target confuses means with ends.
The priority for the planet is to stop net emissions of greenhouse gases, especially carbon dioxide.
Putting too much emphasis on wind, solar and other renewables may block off better carbon-reduction
paths. After decades of investment, it is wrong to leave nuclear power off the table. Carbon
emissions in Germany actually rose because it chose to phase out nuclear power and so burned more
coal. New technologies, such as "direct air capture" systems designed to separate carbon dioxide
from the air, may in time prove vital.
Likewise, greater energy efficiency could reduce emissions by even more than deploying renewables
would. Indians last year consumed twice as much energy from new solar farms. More accurate metering
of energy consumption could encourage companies and households to rein in power demand.
It would be better, as the Paris agreement urges, for countries to focus on reductions in emissions
rather than to set goals for renewable energy. Global emissions have stabilised in the past three
years, which is encouraging. But to stand a chance of mitigating global warming, they must start
falling sharply and keep doing so for decades. The wold will move in that direction with the help of
wind and solar. It will not get there without big advances on every other front as well.