By Earl J. Ritchie

In an earlier post, I established that, with massive effort, it would be possible to generate all electricity and a substantial fraction of transportation energy with renewable fuels. The pace of conversion is said to depend upon political will.

"Will" is not the correct term. Will implies both desire and determination. A substantial fraction of the public do not have the desire. Some do not think it is necessary, some do not want to sacrifice conveniences, some are not willing or able to pay. On one hand, there is a highly vocal contingent that believes anthropogenic climate change is literally a life or death issue; on the other hand, there are groups that do not see it as a major problem or have a vested interest in the existing energy structure. It is difficult to predict the relative influence these two radically different viewpoints will have on how quickly it will happen.

The Gallup Poll results for the past several years show that only about 40% of Americans believe global warming will be a serious threat to them personally. A 2015 Pew poll indicates higher concern internationally, with 54% saying that climate change is a very serious problem and 78% saying greenhouse gases should be limited.

There is a strong component of political orientation in support for carbon reduction measures, both in the U.S. and internationally. In the Pew poll, Democrats score approximately 2 to 3 times higher on questions of climate change concern. The pace of carbon reduction will be significantly influenced by which party is in power.

Expression of concern says nothing directly about willingness to spend on carbon reduction or change lifestyle. For example, the average size of American houses continues to increase. Three-fourths of Americans drive to work alone, and electric and plug-in hybrid cars are currently less than 1% of U.S. auto and light truck sales. The strong correlation between subsidies and renewable energy spending indicates the pocketbook is more important than the environment.

The majority of people just don't put their money where their mouth is.

It's hardly earthshaking to predict the outcome will fall between predicted extremes. A couple of observations can be safely made:

It will happen faster than supporters of traditional energy sources think. There is already considerable support at the government level and the decreasing cost of renewables will favor their use.

It won't happen as fast as the proponents of 100% renewables predict. The rapid growth of solar and wind power is largely due to projects supported by other people's money. As cumulative cost increases, there will be resistance by those paying the freight. This is already happening. The technical and economic barriers that begin to become important with a higher share of renewables will slow implementation further.

Perhaps the best indicators of the pace in the near term are the pledges made in the Paris Agreement. While the agreement is hailed as a milestone, it is generally recognized that the INDCs (Intended Nationally Determined Contributions), if implemented, will not decrease CO2 emissions, will not keep global warming below 2 degrees C, and will not mean the end of fossil fuels. CO2 equivalent emissions rates expected to be attained through the agreement are indicated by the red bars in this graph from the United Nations Framework Convention on Climate Change. Emissions increase throughout the commitment period and end well above the historical levels shown in dark gray.

Note also that limiting warming to 2 degrees C requires the sharp decrease, shown in aqua, immediately after the end of the commitment period. This pattern is the same as has been the case since the first Intergovernmental Panel on Climate Change report in 1990: Each report says we have to start reducing greenhouse gas emissions immediately. Although estimated CO2 emissions have recently flattened, measured greenhouse gas concentrations not only have not decreased, they have continued to increase at an accelerating rate. The discrepancy may be due to errors in the estimate or reporting of fossil fuel consumption from the various countries but, in any case, there is no indication in the measurements that emissions have actually decreased.