Increasingly dire projections of the impact of climate change within this century are often met with morbid acceptance or dismissed as alarmist. Dr. Joe Romm argues that first stage of “climate grief” is acceptance, which is the reverse of the Kübler-Ross model of grief that we personally experience when, say, confronted with a conclusive diagnosis of a terminal disease (cf., physicist Saul Griffith). While Joe notes that what we are accepting is the science, it is my experience that non-scientists often move immediately from acceptance of the science to hopelessness. After all, the scientific reality is pretty stark. Here I will argue this is wrong-headed at any stage of the progression of anthropogenic climate change, and I hope to provide a context in which to understand what the science is telling us about what the twenty-something generation will experience.
In any discussion of the current and future impacts of climate change we must look at the science for what it actually says and avoid jumping to any conclusions about the outcome. The most important thing to understand is that climate change scenarios are projections, they are not predictions. A projection is a conditional prediction, and thus, it does not imply certainty. For example, the current projections for end-of-century global average temperature rise range from 4˚ to 6˚C, but these are dependent on maintaining our current rate of increasing emissions, especially that of carbon dioxide. There are many reasons why the rate of emissions might change, resulting in more or less warming as we move forward in time. For example, changes in economic activity strongly affect the rate of carbon dioxide emissions. The recent recession resulted in a decrease in the growth rate of emissions from about 3.1% per year to -1.3% for 2009. Thereafter, the world’s economic engine cranked up considerably, increasing the growth rate of emissions to 5.9% per year in 2011. To be sure, such small changes in the growth rate of emissions have little potential to slow the rate of warming. Another factor that is outside the conditional prediction of this scenario is the rate of positive feedback from natural sources of greenhouse gas such as the thawing permafrost, or the well documented process of worldwide forest decline. These factors could considerably accelerate the rate of warming and take us well beyond 6˚C. In all candor I must say that there are very few factors that will significantly slow the rate of human-caused emissions, short of concerted and intensive efforts at mitigation. Wildcards that could change the future include unpredictable events like an asteroid strike or volcanism sufficient to put aerosols into the stratosphere and thus cool the planet. Just how lucky do you feel?
What would a 4-6˚C planet in 2100 be like? Paleoclimate studies provide a guide for understanding the kinds of changes that we can expect, although we are driving the rate of climate change far faster than at any time in prehistory. Drawing on such evidence we can safely say that global average sea level will be somewhere between 1 and 1.5 meters higher, and this will require massive investments in infrastructure to move civilization away from coastlines. The majority of us live within 50 miles of a coastline. Assuming that we pass a tipping point in the melting of the major ice sheets, sea level would continue to rise for at least 300 years, eventually exceeding 20 meters. In addition, we can say that by mid-century higher temperatures will amplify emerging and re-emerging infectious disease, reduce human work capacity, increase heat related mortality, and generally effect every aspect of human life. After mid-century, as temperature increases exceed 3˚C, major adjustments in food production will be required to avoid widespread crop failure and hunger. Because there will be considerably more energy aloft, weather will become progressively more extreme as energy is dissipated through creation of storms, droughts, hurricanes, tornadoes, and the like. By the end of the century it is questionable whether or not civilization as it is currently manifested will be able to continue. There has never been a time in our history as a species that we have experienced such a climate. Such changes will challenge every aspect of our ability to adapt, and it is likely that there will be much suffering. Will we go extinct? I doubt it, but this begs the question of human quality of life under such conditions. In sum, it is arguable that natural selection did not endow us with the traits to prosper in such a climate disrupted world.
The current generation of young adults in college will experience an increasingly dangerously disrupted climate during their lives. We have only limited ability to affect this outcome because there is a 30-40 year time lag in the equilibration of ocean heat loading with the atmosphere. About 93% of energy imbalance caused by the greenhouse gases goes into the oceans, and it takes time for this energy to be expressed in the climate system. Evidence of massive ongoing change in the oceans is seen in the slowing of the Gulf Stream and widespread changes in salinity and surface temperatures. The hydrologic cycle has sped up about 40% since the mid 20th century, and the rate of acidification of the oceans is faster now than at any time during the previous 300 million years. Accordingly, this generation of students must prepare to adapt as the impacts of these changes ramify across the planet. Even casual inspection of higher education shows that institutions are generally failing to prepare students to face these challenges. As educators we have an ethical obligation to do so. This ethical imperative has been the primary motivation for the development of sustainability science at Unity College.
What about the offspring of the twenty-something generation? Their situation is far from hopeless, but we cannot stay on a trajectory to reach 4-6˚C warming. We have enormous potential to salvage a livable planet for my grandkids (I am 59), but we must move quickly with concerted worldwide programming to eliminate fossil fuels from our energy portfolio (see Postscript below). The window of opportunity for making this change is small and getting smaller the more we delay. The International Energy Agency estimates that we must begin these changes by 2017 in order to avoid incurring sunk costs associated with building infrastructure such as power plants and cars that are dependent on fossil fuel technology. Indeed, the most recent version of the IEA World Outlook indicates that the growth of oil and natural gas output in the U.S. is pushing us rapidly in the wrong direction. As McKibben and many others have correctly pointed out, we simply must leave this carbon in the ground. It is clear that the fossil fuel corporations have no intention of doing so, and we have no choice but to do everything we can to stop them and change how we power civilization.
A new book by Andrew Simms makes the point that the necessary transformation away from fossil fuels will open a wide range of new jobs and economic opportunities. Moving to an economy based on renewable energy will create a new “adaptive zone“, thus diversifying and renewing the world economy, similar to the way that the ability to fly diversified avian species. Like most of us at Unity College, he sees a different future: a future in which ecology is integrated with economy, and we do not externalize the costs of our lifestyle onto future generations. He provides scenarios for a new beginning, and these scenarios are largely consistent with the implementation of the principles of sustainability science. If we implement policies to create Simms’ world, we can cancel dire climate projections and the demise of civilization. Winston Churchill said, ” It is not enough for us to merely do our best – we have to do what is necessary.” As has been said by many, we have just enough time, starting now.
Postscript: Just published in Nature Climate Change is an analysis of the U.N. program Sustainable Energy for All that shows that we have the technology and economic means to limit warming to 2˚C and largely eliminate poverty. This is yet another paper in a long and growing list that shows that if we overcome social and political barriers we can cancel the apocalypse.