Why we need a tax on carbon emissions

WHY WE NEED A TAX ON CARBON EMISSIONS

Many, if not all of you, have gone into a bookstore and seen the series of books entitled  “The Dummy's Guide to this, or that or the other thing”.  So let me begin by giving you my version of “The Dummy's Guide to Global Warming”.

Generally speaking, the earth's average temperature depends upon two factors: the amount of energy pouring down on earth from solar radiation ; and the offseting effect of the energy loss as the earth radiates or reflects heat back into space.  For thousands of years that average temperature has fluctuated up and down within a very narrow range as the energy gain from the sun was more or less counter-balanced by the energy loss from the earth.

Over the past 200 years or so we have poured more and more carbon dioxide and other greenhouse gases into the atmosphere and created the equivalent of a thicker and thicker insulating blanket around the planet. As a result, the world average temperature has risen by more than one degree celsius since the start of the industrial revolution and will probably rise by another degree or more if we do not stop burning fossil fuels by mid century.  There will continue to be annual fluctuations but what matters is the long term trend not the year to year or even decadal temperature variations.  

The cumulative amount of greenhouse gases in the atmosphere can be likened to the setting on your home thermostat.  The greater this amount the higher will be the setting of the world's thermostat and the greater will be the ultimate temperature rise. There is already more carbon dioxide in the atmosphere than there has been for the past 800,000 years and the amount keeps growing daily. The resulting temperature rise will last for more than a thousand years.  

As a species we are now faced with two choices: continue burning fossil fuels until the world temperature rises to a level where most forms of life cannot survive; or stop burning fossil fuels.  If you believe that most people will do this voluntarily then you have a much higher degree of faith in your fellow humans than I do.

So what can we do?  Jim Hansen,  who warned U.S. politicians in 1988 about the perils of global warming, has proposed one solution based on his belief that as long as fossil fuels are the cheapest form of energy we will continue burning them (a belief which I happen to share):  put an ever increasing price on carbon dioxide emissions until we are forced to change our behaviour.

So there you have it: the dummy's guide to global warming and the reason why a carbon tax is considered essential.

Unfortunately that is only global warming 101 where the underlying science is well established.  We also need to consider tipping points. An avalanche is often chosen to illustrate what is meant by a tipping point. The snow on a mountainside appears to be stable.  Then something happens and suddenly an uncontrolable avalanche is underway. The avalance ends soon thereafter and a new stable state is reached. The event which caused the transition from one stable state to another is known as a tipping point.  I know of three such tipping points which concern many scientists because they know that while they are likely to occur there is no known way to predict when that will happen.  I will now address each of these in turn.

The snow and ice caps which cover the Arctic and Antarctic regions of the world and the glaciers found in many mountains act like gigantic mirrors reflecting much of the solar radiation falling on them back into space thus helping to keep the planet's temperature rise under control.  This phenomenon is known as the earth's albedo and scientists are concerned that reductions in the albedo due to the melting of the ice caps could result in a relatively sudden and uncontrolable rise in global temperature especially as the Arctic ice cover has been decreasing much faster than scientists had expected.

The second tipping point of concern comes from the vast quantities of biomass accumulated over millenia in the permafrost of Alaska, the Canadian Arctic and Siberia.  As the permafrost thaws bacteria begin digesting the biomass and producing carbon dioxide and/or methane, a greenhouse gas over 100 times as potent as carbon dioxide in the short term.  The danger here is that another tipping point might be reached if too much methane is released.

The third tipping point is also methane related. The ocean in the East Siberian Arctic Shelf is only some 50 metres or so deep. Lying on the ocean floor are vast amounts of methane trapped in ice (clathrates). Scientists have found large volumes of methane are already being released from these clathrates, believe that the largest mass extinction of life on the planet some 250 million years or so ago was caused by the vast release of methane into the atmosphere from the ocean floor and fear that this could soon happen again since clathrates are not very stable.

Each of these tipping points could result in a sudden and rapid increase in the global temperature.  Such sudden increases have occurred in the distant past within as little as a decade.  The consequences of such large temperature increases are so serious that they must be avoided at all costs reinforcing the need to tax carbon emissions as soon as possible.

Many reading this article will deny that the amount of greenhouse gases in the atmosphere has anything to do with global warming.  The science on this point is quite clear. Carbon dioxide absorbs infrared radiation emanating from the planet preventing that radiation from escaping into space and thereby upsetting the balance between the heat gain from the sun and the heat loss from the planet.

Others will argue that, because of its relatively small population, Canada has been only a small contributor to the global warming which has occurred to date and can have little effect on future warming.  I fully agree but would argue that change must begin somewhere and that as the largest per capita contributors to global warming we should set an example for other countries, particularly India and China, encouraging them also to take action.

Still others will argue that it is already too late.  That may be but we won't know for sure until it really is too late but quite frankly I'd rather go down fighting than simply sitting back waiting for the worst to happen.  What worries me the most is what is happening in the Arctic.  As the ice cap melts and less energy is relected back the temperature in the Arctic rises.  This leads to increased release of methane from the permafrost and clathrates which leads to more melting of the ice cap.  This vicious circle of one warming effect feeding on another could easily lead to an uncontrolabe increase in the global temperature.  I am very worried that the window of opportunity for acting to control global warming is closing fast.

If you do not believe in Hansen's approach or something similar then by all means vote for the Doug Fords and Jason Kenneys of this world and support the proponents of greater tar sands extraction.  Believe me your grandchildren will curse you for doing so.   Otherwise elect politicians who are more interested in the long term effects of climate change than those more interested in their own immediate fortunes and pressure those now in power to take action.

Remember, most politicians are followers not leaders, and it is not until a sufficiently large number of you force them to take appropriate action will anything meaningful be done.  The transition to a zero emission world will not be pretty  but the alternative will be much worse.  Your future is in your hands.