Renewable Energy, Nuclear Power and Galileo

Renewable Energy, Nuclear Power and Galileo

Renewable Energy, Nuclear Power and Galileo: Do Scientists Have a Duty to Expose Popular Misconceptions?

James E. Hansen

Climate scientists have long warned of potential catastrophic effects of unchecked fossil fuel use.  Public awareness of the climate threat has increased.  Yet growth of carbon dioxide (CO2) in the air, the main driver of climate change, has accelerated inexorably, as nations use cheap fossil fuels to power their economies.

Governments recognize the climate threat, universally endorsing the Framework Convention on Climate Change[1], with the objective of avoiding dangerous climate change.  Yet governments continue to encourage the fossil fuel industry to extract almost every fossil fuel that can be found, including the most carbon-intensive and dirtiest fuels such as coal, tar sands and tar shale.

How can governments be so unresponsive to a public need?  “It’s not dumbfounding,” you may say. “The fossil fuel industry uses its enormous resources to influence public opinions and government policies.”  Certainly they do, but that is only part of the story, and that part of the story has been reported reasonably well.

Here I present climate and energy data to help expose popular misconceptions about energy.  These misconceptions have a greater impact on prospects for stabilizing climate and preserving the remarkable life on our planet than fossil fuel lobbyists and climate change deniers will ever have.  First I must present data for what I call the “carbon math” and the “energy math.”

Carbon math

A specific carbon math is beginning to be appreciated by the public and policymakers, thanks to a dogged “do the math” tour and advocacy by Bill McKibben and his organization.  The goal of, eventual return of atmospheric CO2 to a level no greater than 350 ppm (parts per million), was born several years earlier.  It had become clear that CO2 should peak at less than 450 ppm and eventually decline to no more than 350 ppm, if we are to retain a planet closely resembling the one that we know and love – a planet with reasonably stable shorelines that preserves the abundance of other species, species whose services humanity so enjoys and takes for granted.  The scientific basis for this conclusion was documented in papers[2],[3] by authors with a broad range of relevant expertise.

The implication of the carbon math is that most of the remaining high-carbon fuels – coal and unconventional fossil fuels such as tar sands – must be left in the ground.  The world must move rapidly to clean carbon-free energy, or we will leave our children and future generations a deteriorating climate system spinning out of their control.

Energy math

Governments are not entirely ignorant of the carbon mat

h, but their concerns about energy usually outweigh concerns about carbon.  Therefore, it is important that the energy math be well understood, as well as the relationship between the carbon math and energy math.  I will argue that there are misunderstandings or misconceptions of the energy math, which can almost be characterized as myths.  Let’s first examine some fundamental carbon and energy data.

global energy consumption by source


Fig. 1.  (a) Global CO2 annual emissions from fossil fuel use and cement manufacture, (b) world energy consumption (excluding wood).[4],[5]


Carbon (CO2) emissions did not decline following the 1997 Kyoto Protocol.  Indeed, emissions and even the growth rate of emissions accelerated (Fig. 1a).  The largest growth of CO2 emissions and energy use was in China, where provision of electricity expanded to more than 90% of the population, lifting several hundred million people out of poverty.[6]  Coal use caused most of the emissions growth and coal is now the source of nearly half of global fossil fuel carbon emissions (Fig. 1a).

Fossil fuels provide more than 85% of the world’s energy (Fig. 1b).  One misconception discussed below concerns the fallacy that renewable energy is rapidly supplanting conventional energy.  Total non-hydro renewables today offset only about one year’s growth of energy use.

Energy use and carbon emissions in developed countries approximately leveled off over the past 35 years (Fig. 2), where developed countries are defined as Europe, the U.S., the former Soviet Union, Japan, Canada, and Australia.  The leveling of emissions from developed countries is in part a result of outsourcing of manufacturing to developing countries.

Global carbon emissions (Fig. 2a) are the sum of exponential growth curves for developed and developing countries, with developed country growth climaxing about 1970.  Energy use in developed countries continued to increase modestly after 1970 (Fig. 2b), but carbon emissions stabilized because the increased energy was provided mainly by nuclear power.

energy consumption


Fig. 2.  (a) Global CO2 annual emissions (log scale), (b) global energy consumption.


Global energy consumption will continue to rise for decades.  Why?  First, population is likely to reach about nine billion before it begins to decline, even in the best case.  Second, developing world energy use is still rising (Fig. 2), as it must to achieve living standards that allow their emphasis to be on more than survival.  Even China, though most of its population is now above the poverty line, will use more energy, because its economic development and the well-being of its citizens are not yet at the point where energy needs level out.  Third, in the developed world, despite improving energy efficiency and assertions by some people that they will live low energy life styles, there is no indication of a dramatic decline in overall energy use.  People travel and plan to continue to travel.  Small declines in energy use in the developed world so far are a consequence mainly of outsourcing of manufacturing, not low-energy life styles.

Abundant affordable energy is essential to address the world’s economic and environmental problems.  Energy is needed to achieve adequate living standards and a stable human population.  Economic progress makes it possible to pay attention to the environment, as required if we are to share the planet with the other species, which are needed for our own well-being. With economic progress fertility rates in most developed nations have fallen close to or below the level required for population stability or decline. I believe that the best hope for preserving Earth’s environment and its invaluable abundance of life is through intelligent economic development, and economic development requires a substantial level of affordable energy.

Fossil fuels provided the energy that today’s developed world employed to reach its current standard of living.  Unfortunately, if the developing world follows that fossil fuel path, there will be no winners – the carbon math makes that clear.  Yet if fossil fuels provide the only realistic available path to development and improved living standards, that path surely will be taken.

It is easy to blame governments for the fact that we are marching inexorably toward climate disasters, as if humanity were a bunch of lemmings scurrying toward a cliff.  I have argued that politicians are well-oiled and coal-fired,[7] and, indeed, documentation of that exists.[8]  However, this is surely not the only cause, and it may not be the most important one.

Indeed, a case could be made that politicians have been pushed into a situation such that they have no choice but to approve continued coal-burning, hydro-fracking for increased gas and oil production, and pursuit of oil and gas in extreme and pristine environments.  For the sake of understanding the present situation, we must introduce and combine some basic economic, energy and carbon facts.

gross domestic product


Fig. 3. Real gross domestic product[9] of several nations (a) and global GDP and its annual growth rate (b).  Annual growth rate of GDP, blue curve in (b), is the mean annual growth over  a 5-year period.



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