A carbon limit
The United Nations panel on climate change released an extraordinary report this week making concrete the threat and challenge humankind faces in responding to the reality of climate change.
The Intergovernmental Panel on Climate Change is the international body that has been gathering together all the scientific work from around the world and assessing what it tells us about climate change and manís role in causing it. The latest report is more certain than ever that human activity is largely responsible for climate change and that we will feel the effects for centuries.
For the first time the panel described an upper limit for carbon dioxide in the atmosphere to avoid the most dangerous effects of climate change. To keep temperatures from rising more than 3.6 degrees Fahrenheit, no more than 1 trillion tons of carbon can be burned. Since the dawn of the industrial age, we have already burned about half of that total. The report estimated that there are more than 3 trillion tons of carbon in the form of fossil fuels remaining in the world.
This finding underscores a point increasingly stressed by climate change activists ó that from now on we must find a way to leave in the ground a large portion of the carbon available to us.
Much work has been done to shift the world to more efficient combustion of carbon ó including the development of cleaner automobile engines and more efficient buildings. Lately, with the rush to develop natural gas reserves in the United States, there has also been a renewed emphasis on switching to fuels that are less carbon-intensive.
These changes help to slow the burning of carbon, but they do not alter the stark fact described in the U.N. report: We can burn maybe another 500 billion tons of carbon and thatís it. Beyond that human civilization courts self-destruction. Thatís why the battle cry of activists such as Bill McKibben of Ripton is that the fossil fuels available to us must simply be left alone.
McKibben is a leader in the fight against the Keystone XL pipeline, which has been proposed to carry oil from the tar sands of Alberta to refineries in Texas. Opponents of the pipeline have offered a variety of reasons for their opposition, but the most fundamental grounds has now been bolstered by the latest U.N. report ó that we must leave the oil in the ground.
It is not an easy argument to make. Our economy is based on fossil fuels. Our freeways are clogged with cars and trucks spewing carbon by the ton into the atmosphere every day. As we make the transition to other fuels, we canít instantly pull the plug on gasoline, diesel, fuel oil, natural gas and coal.
We have already set in motion the processes of climate change, and we have witnessed its effects. The last 50 years have been the hottest since the beginning of the Industrial Revolution. In the last decade records have fallen year by year for high temperatures, rainfall levels and other signs of extreme weather. New sea routes are opening up in the arctic because of the melting ice cap.
Climate change activists are increasingly turning to a kind of radical rejectionism, opposing any sort of project that allows for the future use of any form of fossil fuel. In order to allow humankind to keep its consumption below the 1 trillion ton mark, this rejectionism makes sense.
But since it will be impossible simply to pull the plug on fossil fuels, sensible choices will have to be made in the short term in order to allow us to make the shift away from fossil fuels in the long term. A program that promises hardship and disruption now is not likely to win many converts, even if it is meant to avoid hardship and disruption in the future. At the same time, we need to get used to the idea that we can burn only so much additional carbon and then we will have to stop.