Months and years pass by, yet there remains a pervasive silence among people with political influence on what must be done to limit and then reduce the amount of carbon dioxide emitted into our environment from our burning of fossil fuels. Do the world’s leaders not realize the catastrophe awaiting us if CO2 is allowed to continue to increase? Do they think that worrying about the economy and employment will be in any way meaningful in the long run if humanity is soon thrown into chaos from the effects of Earth’s warming?
If most of our leaders are hesitant to act because they don’t quite believe the forecasts made by scientific experts in this field, those of us in science must help them face what is true. The authors have over 70 years of experience in chemistry: one of us carried out high temperature research and taught physical chemistry at both the undergraduate and graduate level; the other spent a career with a large nickel-producing company including time as an executive officer responsible for health sciences. We are committed to bringing science to society. There is no more important task right now than to give decision makers appropriate facts about Earth’s energy imbalances caused by increasing levels of carbon dioxide in the atmosphere. Our view of this issue comes not from approximations or guesswork, but from facts. Simple and straightforward, these facts tell us what every undergraduate in chemistry or physics can understand: that Earth is now receiving more energy than it is able to emit without increasing its temperature.
When talking about the effect of greenhouse gases, we believe several benefits are achieved in talking about energy increase instead of climate change. First is clarity: climate is best defined by regions and people have difficulty understanding what is meant by the global climate. Discussions about the global climate are fraught with confusion because there are no agreed upon parameters , methods of calculating whole-Earth averages, or sets of data. Often such discussions have the aura of imprecision and doubt.
It has become customary to use Earth’s temperature as a surrogate for “climate”. This use probably originated from the fact that, when the energies into and out from a body are equal, the temperature of the body is a measure of that energy. However, if a body (e.g., Earth) is not in steady state due to energy flux dynamics, then the average temperature is not a measure of that energy. For instance, if some of the energy becomes temporarily sequestered beneath the surface, then it will not initially increase the surface temperature. This may cause people to erroneously conclude that the rate at which energy is entering has diminished. The error results in not recognizing that the sequestered energy still remains as energy that will be released at some later time.
A second reason that talking about Earth’s energy increase is more appropriate than talking about temperature increase is that Earth’s temperatures must be averaged over space and time and this average depends on the specific measurements chosen. People can disagree about the correct data set resulting in disagreements about trends. And such disagreements lead to confusion.
Dealing with energy overcomes these deficiencies in using temperature as the measured indicator of changes in Earth’s “climate”. Moreover, Earth’s energy increase can be found by straightforward calculation. First, we accept that the energy being received by Earth comes from the Sun. Second, we know that some of this energy is reflected by the atmosphere and Earth’s surface and is sent back out to space. The remaining energy is absorbed by Earth and is the primary energy “in”. We then turn to the energy “out”
The starting point for knowing the energy out is to calculate the radiant energy emitted by Earth’s surface. The distribution of radiation emitted by a body at a given temperature has been known for over 100 years. For a body having Earth’s temperature, this radiation is infrared. It is necessary to know whether any components of Earth’s atmosphere can absorb this radiation. It turns out there are several, but the most important at this time are water vapor and carbon dioxide. The amount of radiation absorbed by these gases is governed by Beer’s Law and has been quantitatively known for over 50 years. Indeed, careful measurements of the amount of carbon dioxide in the atmosphere have been made with excellent precision by scientists in Hawaii and we are not aware of a single scientist who questions the accuracy of these measurements. They show a definitive CO2 trend upwards since they began these measurements 50 years ago. The infrared absorbing gases prevent a portion of the energy from returning to space after being emitted by Earth’s surface. This can be considered a secondary energy in. Adding the primary and secondary energy inputs shows that the total input is higher than the total energy output. This energy difference is translated into heat energy in the atmosphere, with over half being transferred to Earth’s surface.
At the present time, the increase in CO2 in the atmosphere is 2 parts per million each year. The amount of energy this yearly increase of CO2 can capture can be calculated accurately using science that has been known for 100 years. The answer is 380 billion megawatt hours, give or take a few percent. And recall this is not the total infrared energy captured by CO2 in the atmosphere; it is only the increase in energy from CO2 increasing from 398ppm to 400ppm over the last year.
To relate this to events on Earth, 380 billion megawatt-hours is more than 10 times the energy needed to melt the 300 km3 of ice that disappeared from the Arctic last year. It is a large increment of energy. And it is occurring year after year. No sensible person can deny the science that underpins this energy calculation. And no reasonably intelligent global politician can argue with the urgent need to take rapid action to slow down and then reduce this energy imbalance.
Hugo F. Franzen, Professor Emeritus
Ames, Iowa, USA
Bruce R. Conard, President
Oakville, Ontario, Canada
